Electronics (Part 2)

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C. Power Supplies (Batteries, Holders, Converters) Fuses, & Heat Sinks

Barrel Jack notes:

  1. 2.1mm barrel jack – default is center positive, i.e. inside is positive, shaft is negative. Read to see if center negative (opposite polarity) is specified.
  2. Polarity reversing barrel jack cable 2pc. for £5.60 (£2.80 ea) – useful for centre negative guitar effects pedal and other musical equipments
  3. 3-way barrel jack connector cable £4

  1. DC Power Supply (wallwart, 110/220V AC to DC) with 2.1mm barrel jack
    Notes:

    1. wallwarts are unregulated power supplies. Use 100uF capacitors across their inputs to smooth them. E.g. 9V wallwarts measured at 9.19V and 9.13V (not bad).
      Wallwarts & Brick Basics | How Power Supplies are built: Transformer+Rectifier+Smoothing+Regulator

      1. Breadboard Power Supply MB-102 – convenient form factor plugs into 400+-tie points breadboard (watch out to align +/- with red/blue power stripes), takes 5VDC USB power input or 9VDC wal-wart, converts down to 5V or 3.3V, or both to have two power rails, £4.67 next day, or 3pc for £3.79 (£1.26 ea)
      2. 9V DC 1A 9W £3.95 (two weeks), £4.77 (five days), or 2A 18W for £5.79, five-days, or £8 next day. Also: Center negative 1A £9.74 next day (for e.g. guitar pedals and other musical equipment).
      3. 5V DC 2A 10W: £4.03ea 1 week (ebay), or £3.38ea (MOQ2) ebay, £3.41ea (MOQ2), or £4.69 in 2-3 wks, or £7 next day
      4. Converter cores: 5V DC switching power supply 2A, 10W, no cables, £2.39 2.8″ x 1.5″ x 1.2″ compact

    2. Batteries and Holders
      References:

      1. AA have better energy density than 9V batteries: 4.6x more energy, for 3x worse weight and 2x worse volume
      2. Camelion battery information | Table: Internal Resistance of Batteries Used batteries have higher resistance, upto 5x | List of Battery Types Thought all 1.5V batteries were the same? They’re not. Read to understand the properties of different types of batteries. | Zinc Carbon batteries can be 25% cheaper per unit than Alkaline batteries (18p vs. 23p), but you’re typically getting less for your money electrically, except in low drain, intermittent use applications. | When a Lithium battery gets hot… remove, put in open air, cover, let cool. Do not use again | Battery descriptions and stable voltages | CR123 safety | Manually recharging Li-ion/Li-Po batteries with a desktop power supply – punchline, first run at CC (constant current) and the voltage will rise, then charge at CV (constant voltage) and the current will drop trickle charging the last bit of the journey | Li-Po slim high density various shape batteries – charging/building tutorial

        Other batteries: 18650 15969

      3. Table: Power Specs of Common Batteries

        Electrical capacity of common battery types.
        Source: https://daycounter.com/LabBook/Battery-Capacity-Comparison.phtml

      1. Battery contacts kits for direct PCB insertion (instead of holders): Contact plate spring kits, 10 pairs for £2 (20p each pair), ebay, Leaf spring kits,
      2. LiPo batteries, high density, thin – example: 3.7V $12 next day
      3. 9V batteries:
        1. Standard current: Current price: 15 for £11.15 (74p ea) 4 for £5.50 (£1.38 ea) or 4 for £6 (£1.50 ea) or 8 for £7.50 (94p ea) or £20 for 24pc (83p ea)
        2. High current: 9V battery high current, £1.59
        3. 9V Battery Clip Connector (Wiring Harness), RECOMMEND: Hard Plastic not Faux Leather which has poor connectivity: £3 for 5
        4. 9V Battery Holder (open), two types. With loose wire £3.55 for 10pc (35p ea, 4 weeks), or £5.00 for 10pc (£50p ea., 4 weeks) or £5.55 for 10pc (£55p ea, 4 weeks), or with DC barrel plug: £11.50 for 10pc (£1.50 ea, 4 weeks),
        5. 9V battery box with barrel plug, Lowest price: 80p ea (MOQ1). Current price: 10pc for £6 (60p ea) or £4.40 ea (MOQ1)

      4. 3V Coin Cell Battery:
        1. CR1220 3V coin cell (smaller), Li ion: £1.65 for 5pc, (33p ea) or £1.60 for 5pc, (32p ea)
        2. CR2032 3V coin cell (button) batteries (thicker than 1220), Li ion: Low: 10 for £1.79 (18p ea). Now: £4.60 for 20pc (23p ea) or 20 for £5 (25p ea), or 20 for £6 (30p ea) or 10 pc for £4.00 (40p ea.), or 10 for £4 (40p ea.)
        3. CR2032 holder: open-holder lowest price £1.08 for 20pc (5p ea) or 82p for 10pc (8p ea), or £4.50 for 20pc (22p ea), or £5.40 for 20pc (27p ea, 3 wks), or £6 for 20pc (30p ea, next day), polarity: + is at the raised neck of the holder; (to see how to remove the battery from the holder later, see here) Enclosed-holder: CR2032 holder with wire lead and button 68p (need voltmeter to identify polarity of the lead wires as they are both white). Vertical open holder: Lowest: 56p ea, Now: 5pc for £4 (80p ea.)
        4. CR2032 6V double coin cell holder: Dual holder enclosed case (6V) with on/off switch and wire leads, 3pc for 90p (30p ea)

          Using the double coin cell holder is not obvious: Cell 1 (closest to wires) goes in with + side up; Cell 2 (furthest from wires) goes in with + side down.

      5. 1.5V Button Cell Battery: LR41, LR1120, LR1130, LR43, LR44=AG13 from 30mAh to 120mAh
        1. LR41 button cell (1.5V): 10 pc for £1.86 (19p ea.)
        2. LR44 button cell (1.5V): 10 pc for £1.85 (19pc ea.)
        3. LR1130 button cell (1.5V): 20pc for £1.88 (9p ea), or 10pc for £1.84 (18p ea), or 10pc for £2.30 (23p ea), or 10pc for £3.25 (33p ea) same day
        4. Holder for LR41, 100pcs for £8 (8p ea.) and alternative
      6. MN21 23A 12V wireless doorbell battery, 2 for £2.28 (£1.14 ea) same day, or 5 for £3 (60p ea) 2 days
      7. Li-Ion 3V Safety Precautions for Lithium batteries
        1. CR123A (CR17345) (3V) Li ion: 2pc for £2.48 (£1.24 ea) or 2pc for £2.55 (£1.28 ea.) or 18pc. for £17 (95p ea) 960 mAh batteries boosted to 5V. These deliver high current and maintain stable voltage for the duration of their life (10 years), so are essential for battery powered motors, and other projects with sustained current draws of 150mA or more. Design details WARNING: If you drop this battery you should assume it is internally damaged, and discard. If you use it, you will find erratic voltage, and it will start to get hot, and a chain reaction may start that causes it to get hotter slowly even if not connected. In this case, put it outside and cover it with a saucepan for a few hours and then you can safely recycle it in a battery recycling center.
        2. Battery holders for CR123A: Best price 24p ea. (2019). Currently: 10pc for £3.88 (38p ea), or 6 pc for £2.50 (42p ea.) or 5 pc for £6 (£1.20 ea.) next day or 20 pc for £10 (50p ea.)
      8. AA and AAA batteries: Zinc Carbon 30pc AA and 20pc AAA for £8.50 (18p ea)
        1. AA Zinc Carbon (14500, 14mmx50mm) batteries: lowest Zinc Carbon was £4 for 28pc (14p ea). Currently Zinc Carbon £4.60 for 20pc (23p ea) or or £4.00 for 10pc (40p ea.) Camelion
        2. AA Alkaline batteries: Lowest Alkaline was £7.45 for 40pc (19p ea). Currently: Alkaline
          32 for £9.79 (31p ea.) Maxell (Same Day delivery), or Amazon Basics, £13.50 for 40pc (34p ea.), or or high current, 74p (for 2 pc)

        3. AAA Zinc Carbon 1.5V batteries (low current capacity): Low 10 for £2.07 (21p ea). Now: 28pc. Alkaline for £6.23 (23p ea.) or 10 for £3.33 (33p ea). WARNING: Not all batteries are the same — LR03 (alkaline) and R03 zinc carbon are the same nominal voltage but R03 have typically half the current capacity as LR03.
        4. AAA 1.5V batteries Alkaline: Low: 32 for £8.46 (26p ea). Now: 16 for £5 (31p ea), or 20 for £9 (45p ea), or 32 for £12 (38p ea.) Maxell (Same Day delivery)
        5. Battery Holder with Flying Leads:
      9. High Capacity AA batteries: Amazon Basics 8 pack for £15 (1.88 ea), 2400mAh, pre-charged, rechargeable, + charger for £8 w/ Same Day delivery, or Tybatt 12 pack for £20 (£1.67 ea), 2800mAh, pre-charged, rechargeable, w/Same Day delivery, or EBL 16 pack for £23 (£1.44 ea), 2800mAh, not pre-charged, rechargeable, w/ Same Day delivery
      10. 18650: rechargeable 3.7V Li-ion battery (up to 3500mAh). 20700, 21700, and 26650 batteries (up to 6000mAh). Example: 18650 used to replace CR2032 batteries
      11. Block battery 6V Carbon-Zinc battery, 4R25, £5.20 w/ Prime delivery
    3. Fuses Automotive Blade fuse 3A @ 14p ea. from Spiratronics, these blow immediately (< 1sec) when tested by inducing a short circuit with 2x9V batteries in parallel or Assorted glass quick-blow fuses 100 pc. for £2.77 (3p ea.), 0.2A to 20A, 10 kinds, 10 ea., 5x20mm

      Worth testing a batch of fuses before assuming they’ll blow in case the fuses are defective. These cheaper fuses (3p ea.) did not blow despite batteries and wire harness getting hot, smoking and finally melting, and the fuse still had not blown. Better to spend more on quality protection than risk a fire.

    4. Fuse Holders: 5 pc. for £1.47 (30p ea.), clear plastic cover, two-pins, for 5x20mm or 10 pairs for £1.06 (10p ea.), 4 pin per pair
    5. Heat Sinks / Cooling Fins: Heat exchanger can exude heat faster by heat exchange through contact with air. Pure copper (401W/mk) has higher thermal conductivity than pure aluminum (237W/mk).
      1. 8x8x5mm Aluminium 5x for 50p (10p ea) (needs thermal adhesive) or thermal conductive double sided tape
      2. 14x14x7mm Aluminium 5x for £1.70 (34p ea)
      3. 16x8x2mm Copper w/ adhesive tape, £1.35
      4. 8x8x4 Copper w/ adhesive tape, £1.31
      5. 50x25x5mm Aluminium w/ thermal tape, £10 (£2.50 ea), w/ Prime delivery
      6. 13x12x4mm Copper, £4 for 8 (50p ea)
      7. Copper Plate: Foil 10x10cm x 0.2mm – £4.09 or £2.98 for 10x10cm x 1.0mm or £2.43 for 0.5mm (10x10cm) or £6.05 for 10x10cm x 1.2mm
      8. Copper wire: 10m x 1.0mm – £3.74
      9. Thermal Conductive Tape, Double Sided: 20mm for £4.74 or £7.59 w/ Prime Delivery
    6. DC to DC Voltage Converters / Regulators / Power Supplies
      Four types: Wallwarts (AC to DC converter), Boost converter, Buck converter, Boost-Buck simultaneous conversion.
      Two flavors: Fixed output voltage, Variable (selectable) output voltage.
      Two designs: Switching regulator, and LDO (low dropout, non-switching) regulator

      Supply source: selection direct from Canton Electronics (maker of CE012)

      Go-to components: LM2596 (blue rectangle) inefficient, NCP3063 (good but SMT), Wurth 173010542 7805, MC34063A[std temp range] or MC33063A[extended temp range] (dip8), HT7133 LDO (Low-Dropout Regulator has no switching noise)

      Why not to use MC33063 / MC 34063 chips:
      (1) No built-in thermal protection, no built-in over-current protection/fuses: 25V to 5V step-down using MC33063A IC DIP8 when a short-circuit fault happened outside the regulator.
      (2) Inefficient design, ancient chip. Much better chips and designs out there for battery to 5V boost conversion.
      (3) Requires external inductor, schottky diode, proper heat sinking/thermal management to prevent overheating and damage to the IC, external fuse at 500mA at the input voltage to prevent catastrophic short circuit failures
      (4) The higher the switching frequency the better response rate required from the external capacitors used. Switching frequencies anywhere from 50-200kHz.
      (5) Consumes 4mA while idle (wasteful, considering the ATtiny85 consumes 3mA when running at 100% duty cycle.
      WARNING: This is also why not to buy cheap wallwarts that get very hot. If they have the MC33063 inside, would not be good.

      Analysis of NCP3063 (good)

      1. Boost converter (step-up) with input from 0.8V to allow using 1.5V batteries (AAA, AA, C, D, LR41 button, etc.) to power TTL logic circuits even with depleted batteries.

        Fixed output

      2. Adjustable output

      3. Buck-Boost converter
        • Pololu 2836 (S9V11F5), £7.76 next day. 5V out, from 2V to 16V in, ideal for battery power where starting voltage is above 5V before discharge, e.g. 9V cell, or two CR123A in series. High quality name-brand product.
        • Type 3A: w/ USB input interface and LED display. Input: 3.5V to 12V, Output: 1.2V (buck) to 24V (boost) up to 3W power (or 600mA at 5V), with display, USB powered, 60mm x 20mm x 10mm. Lowest price £2 ea. Currently: £6 same day, or 3pc for £10 next day (£3.33 ea). These buck-boost converters are fantastic. On/off switch, smooth potentiometer control, LED display to 1 decimal digit precision, ability to take Vin from pins (you need to solder in female headers) or USB micro or USB A. Can take Vout from screw terminals or pins. Stable reliable power, up step up or step down. Great for regulated output without having to use lower efficiency linear converters
        • Type 3B: 60mm x 40mm x 14mm. Source: £4.00
      4. Buck converter (step-down), Adjustable 4V to 40V with voltage regulator and LED display
        • LM7805 5V Regulator (input 7-35V): lowest price 50pc for £3.53 (7p ea). Currently: 50pc for £6.57 (13p ea.). Datasheets

          LM7805 5V voltage regulator (input 7-35V). Pin 1 (input) shown.

        • LM2596 fixed output – 6-12V down to 5V fixed: £1.79 with easy access pins,
        • LM2596 adjustable output – 6pc for £7.70 (£1.28 ea) next day
          start with c.20 turns CCW (buck, stepdown), CW is boost.

        • Type 4A: 120mm x 60mm x 30mm, 4-40V input, 1.25V to 37V output, i.e. 3V step-down voltage drop, adjustable power out, with display. Source: £1.75
        • Type 4B:5-16V input steps down to 1.25V to 5V fixed voltage output, £4.69
    7. Solar Power
      1. Solar Engine for harvesting weak solar energy – 1000uF to 4700uF capacitors have quick charging cycles (seconds) and can then deliver pulses for twitchy movement.
      2. Tiny Solar Cells 3mmx3mm. The smallest generate 1/2V / 2mA. So you’d need 6-10 of these in series to generate 3-5V, and then arrays in parallel to increase current.
      3. Decent Solar Cell 2.4cm x 2.2cm – generates 3.4V / 12mA. One would be enough for an ATtiny powered computing device.
      4. Beefy Solar Cell 4x6cm. 6.7-8V and 30-44mA
      5. High-Density (Aerogel) Super Capacitors: 0.35F $5 or 1F $5
      6. BEAM Robots using solar power — what are BEAM robotics?

    D. Integrated Circuits (ICs) – Analog (555, LM386, etc.) and Digital Logic (TTL, incl. 74xxx chips, ALU)

    References:

    1. History of ICs and their evolution: SSI (up to 10 transistors), MSI (up to 500 transistors), LSI (up to 20K transistors), VLSI (up to 1M transistors), ULSI (beyond 1M transistors)
    2. GIICM (Generalized Internet IC Manual) has a of all 7400 and 4000 series of IC chips, their pinouts, and notes.
    3. Discussion of ICs and numbers of transistors
    4. Digital Logic and Circuit Design (article with resource links)
    5. 7400 Series of ICs, and sub-family designations
    6. Integrated Circuit (IC) packaging types and history
    7. DIP and Skinny-DIP ICs have standard pin spacing of 0.1″ (100 mils)/2.54mm, compatible with solderless breadboards.
      Shrink-DIP ICs have a 0.07″ (70 mils)/1.78mm pin spacing.

      To go between them, you need a pitch changer. ProtoAdvantage has a wide range of these!
      64-pin 1.78mm to 2.54mm pitch changer – 10 EUR ea. (wire wrap pins, pins assembled) + S&H extra — Note this one doesn’t work with YM2608 — the chip IC is too wide
      32-pin 1.78mm to 2.54mm pitch changer – 6.40 EUR ea.
      With 5 EUR minimum shipping

    1. IC Socket DIP 8-pin 50pc for £3 (6p ea), 16-pin 50pc for £4 (8p ea), 28-pin 50pc for £6 (12p ea), 14-pin, 16-pin, £3.26 (10 pc + 34 pc + 30 pc)
    2. 8-pin SOIC to IC Test Clip $18 Sparkfun, or £3.00 with 2 adapter boards
    3. 555 Timer Chip, 8-pin DIP IC (TTL version, not CMOS version): Lowest price ever: 11p ea (MOQ40), Current price: 22p ea. no MOQ (Spiratronics) 1-2 days delivery, or you could consider this ATtiny85 with a mod that allows it to function as a 555!
    4. 556 Dual timer chip, 14-pin DIP, 10 pc. for £2.60 (26p ea.) (Spiratronics) or 25p ea., no MOQ but £1.29 delivery for 1, £3.49 delivery for 10, so 10 for £6.00 (or 60p ea.)

      The 555/556 timer chips can be used to create an oscillation when run in astable multivibrator mode (flashing lights, or a sound tone). They’re cheap, take 9V input, and are easy to use. 556 chip is a dual 555 in a more compact 14-pin DIP package.

    5. Op-Amps | Op-Amp basics & 13 circuits | Summing Amplifier | General Purpose & Specialty Op-Amps | Top10 op-amps
      1. IC741, LM741, or uA-741 single op-amp 8-pin DIP IC chip – standard – 20pc for £7 (35p ea) next day


        LM741, UA741, IC741 op-amp, 8-pin DIP chip.

      2. LM358 dual op-amp 8-pin DIP IC chip – 50pc for £7 (14p ea) next day
    6. Audio Chips – Sound and Speech
      1. Audio Amplifer IC chip: LM386 8-pin DIP: Lowest price: 10p ea (MOQ5) | Current price: LM386 IC chips x5 for £3.70 (74p ea.) | LM324 14-pin DIP with dual LM386 onboard (useful for stereo applications): Lowest price 5p ea (MOQ10)
      2. Audio Amplifier board, based on LM386, with 10k variable resistor to provide volume control, and pins for speaker: Kyrio 10x for £10 (£1.00 ea) next day good for quick applications instead of making your own board, but removes the ability to modify the produced sound (gain, bass boost, etc.)

        LM386 IC chip is a audio-amplifier that is low-cost, low-power, and requires few external parts to work. It is a differential amplifer (op-amp) amplifying the difference in voltage between V- (usually set to ground with a 10K R pullup resistor) and V+voltage delivering gain from 20-200x. accepts 4V-12V input but best at 9V separate power source from the logic circuit; can drive loads of 4R to 32R, consumes 4mA to 65mA (at 5V), voltage gain from 20-200x or 26-46dB, drives a 0.2W 2″ speaker to be loud enough for personal use in a quiet room, and a 5W speaker plenty loud. Datasheet: National Semiconductor, Excellent explanation and usage reference (hackaday), Arduino instructable

      3. MP3 Sound Chip (download, playback, 4MB/4min recording time, USB upload, USB rechargeable lithium battery), £13 next day with speaker and 4.5V battery module, 4MB/4min recording time, £7.50 4MB/4min recording time, (tried) WT2003S programmable MP3 recorder/player, £4.18 storage 4MB, with USB interface for download of MP3 files, rechargeable battery, Example usage of WT2003S and ATTiny (sparkfun): one, two Instructions: Connect to micro-USB, copy MP3 files, press button to play or stop playing. Press volume while playing to toggle through 5 volume levels. Hold button down all the way through end of one file, then index will shift to next file in queue for next button press. Otherwise will repeat the same track. Have not figured out how to programmatically select which track plays. Better instructions here
      4. Record/Playback Modules/Chips
      5. Speech Synthesis IC chips
        1. SSI201P, 2pc for £20 (£10 ea)
        2. SSI20C89E, £12
        3. TMS5220CNL, 2pc for £5 (£2.50ea)
        4. General Instrument SP-0264-021, £23
        5. General Instrument NOS SP-0256-AL2, £32
        6. UPD7559C, ADPCM, £6
        7. TMS3477NL, £19
      6. Sound Effect ICs: HK6xx chips (HK628 8 sound effects, HK625, HK637-x specific sound effects), HT2884 sound effects,
      7. Honsitak Sound Effect ICs: Catalog, can listen & download datasheet, HK620 (siren, alarm sounds), HK623 (gunfire, laser, bomb, alarm, telephone), HK628 (rifle/bomb/laser gun), HK629 (3 emergency vehicle sirens and machine gun burst), HK637-5 (car sounds), HK637-4 (truck sounds), HK637-3 (baby sounds), HK637-2 (train sounds), HK637-1 (animal sounds), more from Nightfire
      8. UM3561 DIP8 – 4 sound effects (3 sirens + machine gun): Lowest: £1.40 (MOQ2), £1.80ea (MOQ3). Currently: £1.83ea (MOQ2) / £1.53ea (MOQ6), or £1.95ea. (MOQ10), datasheet, schematic, £2.75, good tutorial video. NOTE: This is like HK629 (above).
      9. Music ICs, UM66T-XXX chip (3pin IC + buzzer + battery, video), catalog of chip tunes, UM66T-19L Fur Elise 5x for £1.75
      10. Complex Sound Generator ICs:
      11. Texas Instruments sound generating chips: Heritage TI sn76477 (mixed analog/digital) -> sn76488 (mixed analog/digital + internal audio amplifier) -> sn76489 (purely digital)
        1. (tried) TI sn76477, See my article Modular Sound Synthesis (forthcoming, 2021). £6 ea MOQ of 2 £8.27 GOOD – this is the N pkg with standard 2.54 mm pin spacing. WARNING: be careful that the chips are not the SDIP-28 (skinny DIP) package with 1.778mm pin spacing vs. DIP-28 (standard DIP) package with standard 2.54mm pin spacing. The SDIP-28 package does not fit into standard 2.54mm spaced breadboard/PCB, and therefore is unusable without a custom PCB pitch-changer adapter which costs £12 ea. While datasheet says N denotes standard package and NF/NE denote SDIP-28, this seller has an N chip marked on case but pin spacing is SDIP! list of many sellers, or Another NF, Another NF, £21 converted to 2.54mm pin spacing compatible with standard breadboard. Video demonstration, narrow pitch (will need a breakout board setup, Wikipedia description and schematics. Press coverage in Popular Science (1978 to 2008), Other designs.

          Sound Generator IC SN 76477, £6.08, 28-pin miniDIP (1.78mm irregular pitch spacing)


          Datasheet

        2. (tried) TI sn76489, Sound (Tone) Generator IC. Low: 5pcs for £3.60 (72p ea), Also: 5pcs for £7.44 (£1.09 ea). Article on driving this with code, Excellent description/dev discussion, Hackaday articles. Heritage
        3. (tried) AY-3-8910 (DIP-40) – £2.79 4 weeks, or 2pc. for £4.50 (£2.25ea) 2-4 weeks, or £4.60 10 days or £5.40 4 days, £4.60
        4. AY-3-8913 (DIP-24) – this variant has no I/O ports, which are not needed for sound generation. 5pc for £12 (£2.40 ea.)
        5. Yamaha YM2151 DIP-24, £2.78
        6. (tried) YM2608 DIP-64 – Yamaha sound chip £2.38 WARNING: This is a Shrink-DIP with non-standard 1.78mm spacing. Needs a pitch-changer to use in a solderless breadboard. (This one doesn’t work! Chip is too wide)
        7. Yamaha YM2612 DIP-24, 2pc for £5.08 (£2.54 ea)
        8. RP2A03 – Nintendo sound chip – £38
        9. SID 8580 (9V), MOS6581 (12V) for Commodore 64. On Nano SwinSID form factor selectable by jumper. £13.50
      12. Guitar effects pedal chips – MN3007/MN3101
        Reference: Experimentalists Anonymous: Schematics and Datasheets for Audio effects creation

    7. Digital Logic IC chips
      1. 7400 ICs from Spiratronics, specifically 74HCxx logic ICs. Plan your shopping list ahead of time as shipping is flast rate £1.50 for an order of small size items, whatever quantity. For a budget of £20, one can get 5-10 pcs ea. of ~10 common ICs below, enough to make a range of applied digital logic projects.
        ICs on a shoestring For ~£20, 5-10 pcs of each of the below parts to enable a reasonable selection of digital logic applications.

        ICs on a shoestring For ~£20, 5-10 pcs of each of the below parts to enable a reasonable selection of digital logic applications.

      2. 7404 – 6 x inverters 33p ea, 27p for MOQ 10
      3. 7400 – 4 x 2-input NAND 25p ea., 20p ea. w/ MOQ 5, 18p ea. w/ MOQ 10 (Spiratronics)
      4. 7410 – 3 x 3-input NAND
      5. 7420 – 2 x 4-input NAND
      6. *7430 – 1 x 8-input NAND
      7. 74133 – 1 x 13-input NAND
      8. 7408 – 4 x 2-input AND HC family – 27p ea., 24p ea w/ MOQ 10
      9. 7411 – 3 x 3-input AND
      10. 7421 – 2 x 4-input AND
      11. 7402 – 4 x 2-input NOR 30p ea., 25p ea.w/ MOQ 5 (Spiratronics)
      12. 7427 – 3 x 3-input NOR 22p ea., 19p ea. w/ MOQ 5 (Spiratronics)
      13. 744002 – 2 x 4-input NOR
      14. 7432 – 4 x 2-input OR 23p ea., 19p ea. w/ MOQ 10 (Spiratronics)
      15. 744075 – 3 x 3-input OR
      16. 744078 – 1 x 8-input OR/NOR 44p ea., 38p ea.w/ MOQ 10 (Spiratronics)
      17. 7486 – 4 x 2-input XOR
      18. 747266 – 4 x 2-input XNOR

        DETECT. Encoder – Use case: You have a bunch of 1-bit input signals, and you want to detect which went high (priority order) using an encoded address

      19. 74148 (DIP16) – 8-lines-to-3bits priority encoder, with cascade logic included to allow building 16-, 24-, 32- to 4,5-bit encoders. Takes 8 line inputs (active low inputs) and encodes the ID in binary (active low output). 32p ea. (Spiratronics), but if out of stock then 2pc. for £3.20 (£1.60 ea.) 5x more expensive, or £2.75 ea. (4 days) 9x more expensive, Note, a single 16-to-4 priority encoder chip does not exist, but one can be built from 2x 74148s and a 7408 (quad 2-i AND chip) which preserves the active low outputs. See Figure 2 in the 74148 datasheet. Usage example: keypad – which key is pressed without needing to reserve 8 i/o lines.
      20. 74147 – 10-lines-to-4-bits priority encoder, £6.00 for 2x (£3 ea.)
      21. 74922/74923 – 16/20 key encoders (available since 1995) providing 4×4/4×5 matrix keypad encoding logic. Datasheet

        TRANSMIT. Decoder – Use case: You have a bunch of 1-bit output channels/signals, and you want to dial up using binary code which channel to output to, and then you will set the output value with 1 pin (hi/lo).

      22. 74138 – 3bits-to-8-lines decoder
      23. 74139 – 2x 2bits-to-4-lines decode
      24. 74141 – 4bits-to-10-lines decoder
      25. 74154 (DIP24)- 4bits-to-16-lines decoder, LOWEST POWER (but slower) LS series: 88p ea (best price), now: 10 for £10.74 (£1.07 ea), or 4 for £10.11 (£2.52 ea) or 5pcs for £14 (£2.80 ea). HIGHER SPEED (but higher power and more expensive) HC series (74HC154): £2.10ea (best price) 5pcs for £13, or £2.60 ea.. Usage example: 16 leds, indicate which ID to light up without needing to reserve 16 i/o lines, note only one can be lit at a time; to light multiple LEDs use a shift out register. Datasheet
        To activate multiple lines, can use a shift out register instead, or complement with an addressable latch that stores the state

        RECEIVE. Multiplexer/Data Selector – Use case: You have multiple 1-bit signals (channels) coming in (hi/lo), you only want to use 1 input line, and you want to dial-in which line you listen to.

      26. 74150 (24 DIP) – 16-to-1 data-selector/multiplexer (4-bit channel selection + 1 input line). Usage: use 5 lines to listen to 16 inputs, 4 lines as channel selector and 1 line as shared input to the MCU. 4 pc for £6.90 (£1.70 ea MOQ4, £2.25 ea unit), or £2.48 ea. Usage example: 16 in-feeds, which one to sample from? Usage 2: sample all 16 lines from 2x 8-bit DIP switchs
      27. 74151 (16 DIP) – 8-to-1 data selector/multiplexer (3-bit channel selection + 1 input line). LS family – 10pc for £3.33 (33p ea), or £3.18 ea
      28. 74153 (16 DIP) – Dual 4-to-1 data selector/multiplexer. Use: 2-bits to select which of 4 one-bit channel/signals to listen to, 1 I/O line from chip to MCU. So each of the devices uses 7 I/O lines, for total of 14 for the dual chip, + 2 power). HC family – 10 pc for £2.16 (22p ea) or £2.96 ea

        GPIO Expanders

      29. Use Decoder – only 1 line active at a time
      30. Use shift register – use 3 i/o lines (data, latch, clock) – to independently control 8*N lines, daisy chainable indefinitely
      31. PCF8574 IO Expander – adds 8 i/o lines via 2-wire I2C, daisy-chainable to 64 i/o lines individually addressable. Example
      32. TCA9548A MUX board – can multiplex 8 channels, so multiplexing 8 channels of 8x PCF8574 ICs, one can control 512 (=8×64) line independently — LED display arrays
      33. Other clever techniques also possible
        Note: can use Darlington Array of transistors to avoid pulling high current through logic decoders

        Flip Flops/Latches/Buffers

      34. 7474 – 2 x 1bit D flip-flop with set/reset
      35. 74174 – 1 x 6bit D flip-flop
      36. 74125 – 4 x 1bit tri-state buffer with active low enables
      37. 74126 – 4 x 1bit tri-state buffer with active high enables
      38. 74244 – 2 x 4bit tri-state buffer
      39. 74259 – 8 bit addressable latch – allows to maintain state and set state one bit at a time using a decoder chip e.g. 74138Example
      40. 74273 – 1 x 8bit tri-state D flip-flip
      41. 74374 – 1 x 8bit tri-state flip-flop
      42. 74574 – 1 x 8bit tri-state D flip-flop Spiratronics 81p
      43. 74373 – 1 x 8bit tri-state latch
      44. 74573 – 1 x 8bit tri-state latch
        Shift Registers for independently controlling N GPIO lines (daisy chainable) with 3 pins

      45. 74164 – 1 x 8bit SHIFT OUT register WITHOUT LATCH *NOT RECOMMENDED, see 74595* –SIPO (serial in/parallel out), 14-DIP, HC family – 5pc for £2.21 (44p ea)

      46. 74595 – 1 x 8bit SHIFT OUT register WITH LATCH SIPO (serial in/parallel out), 16-DIP, HC family – 20pc for £1.80 (9p ea), 50pc for £3.30 (6p ea). Pair with ATtiny85 microcontroller for dedicated monitoring service, I2C interface with controlling CPU, and Arduino compatibility
      47. 74165 (DIP16) – 1 x 8bit SHIFT IN register PISO (parallel in/serial out), lowest price HC family – 20pc for £2.85 (14p ea). Current price: 10pc for £2.82 (28p ea) or 10pc for £3.52 (35p ea). Pair with ATtiny85 microcontroller for dedicated monitoring service, I2C interface with controlling CPU, and Arduino compatibility

        Note: Shift registers require 3 lines to control: data, latch, and clock. There is no actual clock required, rather the shifting works when the clock pin is toggled LO/HIGH.

        Excellent Tutorial Video (Sparkfun) on SHIFT Registers

        Counters, Adders, and ALUs

      48. HCF4017BE – Decade Counter, 10pc for £2.62 (26p ea)
      49. 74163 – 4bit binary synchronous counter
      50. 74393 – 2 x 4bit asynchronous counter 47p ea., 41p w/ MOQ 5 (Spiratronics)
      51. 4008 – 4bit binary full adder with carry
      52. 4585 – 4bit magnitude comparator
      53. 74181 – 4bit 16-function ALU Amazon, $16 (£13.16)
      54. 74381 – 4bit 8-function ALU
      55. 74382 – 4bit 8-function ALU with ripple carry and overflow
      56. 74881 – 4bit 16-function ALU

        7-segment display driver ICs

      57. 744026 – (4026B) Decade Counter w/ 7-segment out driver, 16-pin DIP 60p ea. (no volume discount, Spiratronics, Ebay £3.34 for 3
      58. 744543 – BCD-to-7segment decoder/LCD driver with input latch Spiratronics 91p
      59. Hex Driver for 7-segment displays (0-9 and A-F): MC14495P or MC14495P1 – hex to 7-segment out driver, 10pc for £20, or £2/ea, or DM9368: £18.50 for 4pc (£4.63 ea).
      60. Or use ATtiny84 as a lower cost 7-segment driver or ATtiny85 with shift register as 7-segment driver.

        Misc

      61. MC14490 – Hex Debounce Circuits
      62. Memory chips: EEPROM Atmel AT28C16 2KB (2Kx8bits=16K bits), DIP24 package, £13.30 for 2 pc.

    8. Converters
      1. Breakout Boards:
        1. DB15 Parallel Port to 15 pins, £1.66,
        2. DB9 Serial Port to 9 pins, 86p,
        3. RJ11 Telephone to 4 pins, £5.18 (incl. S&H),
        4. RJ45 Ethernet to 8 pins, £5.69,
        5. USB 2.0 Male plug to 5 pins, £2.62 ea. or £4,
        6. USB 2.0 Female plug to 5 pins, £2.62 ea. or £4
      2. TTL Logic to RS-485, £6 (incl. S&H)

    E. Microcontrollers and Dev Boards


    Microcontroller Comparison table: Arduino Nano, Attiny, ESP, etc.

    Sources:

    1. Arduino Nano – 5 board variants
    2. Microchip (owner of PIC and Atmel) Parametric Search
    3. ST Micro MCU finder software
    4. Technido, supplier of 8051, AVR, Arduino, Atmel, and PIC learning/starter kits with dev boards and sensors

    References:

    1. Programming Microcontroller Chips
    2. Forths for Micrcontrollers: To run Forth in a microcontroller, you have a few options: ideally the uC is a von Neumann architecture, not Harvard (most modern MCUs are Harvard architecture, with a few notable exceptions) OR if serial is supported at bootup time you can write a 3-Instruction Forth (I’ve written one that I use for Arduino / Atmega328 MCU).
    3. Make: FPGAs, by David Romano, 2016, £17.30. Read partially online
    4. Making things Move, by Dustyn Roberts, 2011, £14
    5. 8051/52 Microcontroller by Craig Steiner, 2005, £11.50 in Aug 2018 Architecture, Assembly Language, and Hardware Interfacing

    Arduino Nano/Uno (contains Atmega328P)

    References:

    1. Wikipedia: ATmega328 | Arduino Nano | Arduino Uno
    2. Low power consumption for Arduino
    3. 10 ways to destroy an Arduino
    4. Arduino cheatsheet (PDF)
    5. Arduino IDE (using C/C++) (for Windows get the ZIP package (182MB) for portable installation)
    6. RealTerm, billed as “an engineer’s terminal program specially designed for capturing, controlling and debugging binary and other difficult data streams. It is the best tool for debugging comms.” Essential for tethered development and rapid development/debugging.
    7. Forths for Atmega328 and Arduino: Go Forth, Forth on Arduino, CH Ting’s paper on eForth for 328, CH Ting’s slides, GitHub code
    8. AmForth for AVR/Atmel micros.
    9. 3-instruction Forth for Arduino Atmega328 (request in the comments)
    10. Basic for Arduino (Robin Edwards, c.2005)

    Nano

  2. Arduino Nano V3.0 CH340/Atmega 328 (30 pins, 14 digital i/o, 8 analog), program via Arduino IDE (free) using C. Built in FTDI interface to allow programming directly from PC using usb cable (no programmer required). Note: there are now three types: type MINI, type MICRO, and type C depending on the USB connection. I recommend either MINI or type C as the connections are chunky. Micro connectors tend to get damaged over time and with repeated insert/removals.
    Arduino Nano is small, cheap, versatile, installs onto a solderless breadboard for easy prototyping, and has plenty of expansion possibilities (see below for Ethernet and 2.4G wireless versions). Fully functional Arduino compatible microcontroller, able to be programmed directly from your PC using the Arduino (free!) IDE, and has three advantages over the Uno or Mega: (1) can be plugged directly into a solderless breadboard for easy electronic prototyping, (2) USB connection is via lower profile USB mini port instead of standard size USB port, (3) power is direct via pins or USB instead of a standard size barrel connector.

  3. Pinout:

    Arduino Nano board, 30-DIP form factor, with ATmega328P microcontroller, 22 i/o lines + UART, SPI, and I2C serial comms, 5V regulated, or 7-12V unregulated (VIN), and 3.3V.
    Note: User needs to ensure that no more than c. 20mA is sourced from a single pin, with no more than 200mA total sourced across all pins.

    1. Nano v3 board, MINI, ATmega328P, welded, with bootloader, without cable. ATmega328P £5.49ea (MOQ10) with 2 USB cables | £6.75 ea (MOQ4) next day
    2. USB mini cable for standard Nano CH340 V3.0, 30cm: 5pc for £6.79 (£1.36ea).
    3. USB A Extension cable (Male to Female). Best: £1.93 (1m). Now: £2.00 (1m), £4.00 (1m), or £4.49 1.8m, or £2.5, 2m
    4. Nano to UNO Adapter board, $3.70 ea, £18.71 for 3 boards including £11 shipping (£6.25 ea) w/ 5-7d shipping or £2.70 ea (Ebay)
    5. Nano terminal adaptor shield – no need for a breadboard, solid screw terminals breakout each pin. Without Nano uC £12 for 5 (£2.40 ea) w/ Prime Delivery. With Nano uC integrated 2 for £8.90 (£4.45 ea.), or £12 for 5 pc (£2.40 ea.) next day
    6. Nano ethernet server adapter board –
    7. RF Nano, with integrated 2.4G wireless chip & antenna. Lowest cost: £1.50 ea (AliExpress) or £4.77ea (MOQ 4) | Currently: £2.28 (AliExpress) | £2.70 ea (Ali Express) | £7.50 ea (ebay) or £8.75 ea (ebay) or £9.50 (ebay) or £13 (amazon). Note: needs minimum two for applications. Uses micro-USB cable not mini-USB as with Nano (warning: be sure your micro-USB is a full cable with both power and data lines, not just a power charging cable. To upload code in Arduino IDE for Arduino Nano, be sure that you’ve not selected “Old Bootloader” – this is different than the standard low-cost Nano’s that require “Old Bootloader”.)
    8. NRF Short Range Transceiver NRF24L01, 80m range module, standalone boards, config/comms through SPI (pins 9-13), 2.4 GHz band, 125 channels, WARNING REQUIRES 3.3V POWER and Nanos 3.3V out pin is NOT sufficient so USE 5V breakout board, 14mA max power consumption (2Mbps receiving mode).
      “Module includes interrupt request (IRQ) pin which can be used to wake the host microcontroller, from sleep when the module receives a transmission providing great power conservation in battery devices”: Lowest price: £1.35 pair NRF+breakout boards 67p ea | £1.52 pair NRF+breakout 76p ea board MOQ4 (Ebay) | NRF board only: 10pc for £11 (£1.10 ea) or Kuman: 10 pc for £20 (£2 ea) next day, or 5V Breakout Board for transceiver (accepts up to 12V input using AMS1117 voltage regulator to step down to 3.3V): 5pc for £6.60 (£1.30 ea), or 10x NRF24L01 modules for £10 (£1 ea.) next day 5x for £5 (£1 ea).

    9. NRF Long Range Antenna NRF24L01+ 800m range module, 2pc for £8 (£4 ea) or 2pcs for £9 (£4.50 ea) or 3pc for £17 (£5.70 ea), or 3 pc. for £13.60 (£4.50 ea.) or 3 pc. for £13.60 (£4.50 ea.) or ebay

    Atmega328P uC IC
    This chip has 23 GPIO lines (8 pin port PB and PD, 7 pin port PC).
    References:

    1. Wikipedia: ATmega328
      The cool thing about these chips is that they contain an in-circuit programming (ICP) feature using which you can download code into them using some simple hardware and connecting to 6 pins on the chip (1,7,8,17,18,19) and using the built-in SPI (4-wire synchronous serial) comms capability of the chip.

    2. Programming 328P with Tiny AVR Programmer over SPI, or Hookup & usage with AVR toolset (Sparkfun)


      ATmega328 8-bit microcontroller chip in breadboard friendly DIP28 package, c. £2 ea.
      Pinout & hookup schematic/picture.

    3. AVRDUDE command line utility for reading, writing, and manipulating AVR chips
    4. Atmel 328P datasheet (294 pages)
    1. ATmega328P DIP28 chip, breadboard friendly (328 is cheaper and consumes few mA more, 328P finer process allowing SMT and uses few mA less):

    Related chips/boards:

    1. Arduino Uno R3 running Atmel AtMega 328: Lowest price: £8. Currently: £9 same day
    2. Arduino Mega Atmega 2560 R3 running Atmel AtMega 2560 R3: £13
    3. Atmega4809 – available in 40-pin PDIP package, successor chip to Atmega328P
    4. Arduino Uno WiFi (Atmega4809 processor) | Nano 33 IoT (SAMD21, Arm Cortex M0 processor) | MKR 1010 (SAMD21, ARM Cortex M0 processor)
    5. MCP2221A – USB to serial converter chip
      See Atmega4809 on a breadboard


    Atmel ATTINY85/84

    References:

    1. ATTiny Adventures (getting started with ATTiny)
    2. Using Arduino IDE for ATTiny microcontrollers requires ATTiny board files for Arduino by David Mellis (Download ZIP, copy attiny\ to ..\arduino\hardware\.) | Sparkfun ATTiny Quick Reference Sheet & PDF
    3. Device Driver for TinyAVR USB Programmer (Windows) for ATTiny chips: Zadig Device Driver: libusb-win32 (v1.2.6.0). Then ready to program from within Arduino IDE (see Board files above) or AVRDUDE utility
    4. Sparkfun Hookup Guide for Tiny AVR Programmer for ATTiny85. Sparkfun documentation for Tiny AVR Programmer.
    5. Datasheets & Application Notes
    6. ATtiny85 cheatsheet (PDF)

    ATTiny85 is an 8-bit MCU (2005) with 8-bit timer/counter, 2x PWM channels, USI (Universal Serial Interface), 10-bit ADC, Programmable Watchdog Timer, Temperature Measurement, On-chip Analog Comparator, In-System Programmable (ISP) via SPI port, External and Internal Interrupts, 5x programmable I/O lines + reset, 2.7V-5.5V operating voltage. ATtiny84 is also an 8-bit MCU but with 11x programmable I/O lines + reset. It can be programmed using the ATtiny85 Tiny USB Programmer and wiring to connect via SPI (see diagram below).

    From programmer standpoint, ATTINY85 is a RISC (reduced instruction set chip) with 120 instructions, most executed within a single clock cycle, providing up to 20 MIPS (20MHz at 5V, 1 instruction per cycle). Memory model is Harvard architecture with separate Program Flash memory and Data SRAM memory. There are 32 8-bit registers, of which 6 can be used in pairs for 3 x 16-bit indirect addressing (X,Y,Z) into SRAM data memory.


    Wiring diagram for programming a Tiny85/Tiny84 on a breadboard using Sparkfun’s Tiny AVR programmer — you will need 6 wires

    1. Atmel ATTINY85 20PU microcontroller chip, DIP-8 package: lowest price £1.30ea (MOQ10). Current prices: 10pc for £16 total (£1.60ea, offer accepted) or £1.94ea MOQ5, £1.70ea MOQ10 (ebay) or 5pc for £10.64 (£2.12ea, amazon) or £2.30 ea. (amazon) or 5pc (+ 5x 8pin DIP sockets) for £18 (£3.60 ea).
    2. ATTiny84 DIP14 chip (2005): £10.80 for 5pc (£2.16 ea. MOQ5) or £3.52 (Amazon) | Datasheet
    3. ATtiny2313 DIP20 chip: 18 i/o pins. £6 for 4pc (£1.50 ea.)

    4. ATtiny85Programmer Board (can also program ATTiny84, see wiring diagram above): Sparkfun 11801 Tiny AVR USB programmer: £16.73 from proto-pic UK or $16 from Sparkfun US or Make Your Own for less than £5!
    5. DigiSpark ATTiny85 – an integrated Arduino with ATtiny85 at its heart, powered by USB, programmable over USB, having I2C and SPI available directly, with a built-in voltage regulator (though unfortunately not a boost converter or a buck-boost converter). Usage discussion | 3pc for £8 (£2.66 ea) MicroUSB Spark – £1.70 or £3.00 for one (auction)
    6. ATTiny85 Trinket uC (Adafruit), £7.34, this is a fully-fledged USB programmable, Arduino-IDE compatible microcontroller built around ATTiny85 uC.

    32-bit ARM core uCs


    Espressif’s ESP boards

    1. ESP8266-12 NodeMCU WiFi: 4pc for £21 (£4.25ea) next day or 3pcs CP2102 for £16 (£5.33ea) same day | 3pcs ESP-12F Lolin for £13 next day (£4.33 ea) | 1pc for £7.85 | 4pc for £14 (£3.50 ea)
    2. (tried) ESP8266 32-WROOM WiFi + Bluetooth: 3pcs for £19 same day (£6.33 ea) | chip only £2.10
    3. (tricky to use – needs 5V to 3V level converter, and fiddly upload instructions) ESP8266 ESP-01/-01S Serial to Wifi Transceiver Module: 4pcs for £12 same day (£3 ea) | Information from Sparkfun ($7) | Usage discussion

      ESP8266 Wikipedia, and ESP32 (successor product of ESP8266 with ESP32-C3 using a RISC-V open-source firmware chip)

      Difference between ESP8266 and ESP32. Toolchain for ESP32, ESP-IDF, or ESP-Arduino.

    4. ESP8266 Thing Dev Board (Sparkfun) or ESP8266 Thing (Sparkfun) or ESP32 Thing (Sparkfun)
    5. ESP8266 WiFi Module add-on for any microcontroller ($7 ea) (Sparkfun)
    6. ESP8266 dev board, w/ WiFi, w/ pins. £10 for 2pc (£5ea) with Prime Delivery
    7. WeMos / Lolin dev board & system based on ESP8266, w/ WiFi & Bluetooth. Overview & Possibilities, Main page, Lolin store

      Forths for ESP8266, PunyForth

    8. Seeeduino – smallest Arduino compatible board with SAMD21 microcontroller chip (32-bit ARM core) – c.£4 ea., or 3pc for £22 (£7.33 ea)

    Raspberry Pi

    1. Raspberry Pi: v4 desktop power for $35
    2. Raspberry Pi RP2040 – £9 from Sparkfun, £9 from PiHut
    3. Arduino Nano RP2040 – latest uC board with RP2040 (dual-core ARM Cortex M0+with WiFi and Bluetooth integrated, 22 I/O pins, 16MB memory, programmable from browser or Arduino. Article

    Retro CPUs

    1. 25 Microchips that Shook the World, IEEE Spectrum, Bryan Santo, 2009
    2. Motorola/Freescale (6811) MC68HC11xx (48-pin DIP) : Lots of board options, and Forths for them, the MIT Robot Builder boards, with detailed info on the Motorola 68HC11 chip | Mosaic QCard – with integrated Forth RTOS, datasheet, product page, $150 from Mosaic
    3. RCA/Harris 1802: CDP1802ACE, £2 each (Qty 1), or £1.64 each (Qty5). Details here. Neat builds here. 1802 on FPGA. 1802 FigForth.
    4. Motorola 6809 (or faster 6309): MC68B09EP £12.50 qty 1. Example project. Hackaday writeup.
    5. 6502: R65C02P. Hackaday: 50 years old (b.1975) this year. With milliForth-6502. Neo6502 SBC. FPGA (65F02) in DIP-40 form factor, updated for 2025. As a daughterboard for an Arduino. project page. Opcodes page. Origins, Origins 2
    6. Z80.

    8051/8052

    1. 8051 Self Learning Kit, Technido, £74 with 8052 chip (Atmel AT89S52 24PU 1732A), programmer (ATMEGA 8AU 1804 KTG 35469L), 12V power source, expansion board, starter kit of sensors (IR, DC motor, …), and all necessary cables. Comes with experiments/manual that can be downloaded.Video showing how to connect programmer and install first program
    2. 8052 USB ISP programmer, £1.76
    3. USBasp AVR Programmer, get Windows drivers v3.0.7 (digitally signed) here.ProgISP.exe flash programmer
    4. 8051 C compiler (KEIL). Launch UV4.exe for the IDE.
    5. Atmel AT89S52 (8052) chip, 40-DIP format, £6 (=£5.40 chip + 60p S&H)
    6. Crystal Oscillators for uC: 12 values, 60 pcs, 5pc/ea for £10 same day (16p ea), incl. 12MHz for 8051/2, 16MHz for ATMega328P, more. Individual values: 16MHz 10pc for £4.50 (45p ea) | 10pc for £2.65 (27p ea) 45 days | 10pc for £2.42 (24p ea) 45 days | 20pc for £2.84 (14p ea) 60 days |
    7. 8051 Reference Book: 8051/52 Microcontroller: Architecture, Assembly Language, and Hardware Interfacing (bought new for £11.50 Aug 2018); Craig Steiner (2005)

    STM8s (8-bit ARM chips)

    Why this chip? Because it has a Serial UART capability built-in and has an untetherered Forth available (STM8 eForth).

    1. ST Micro STM8S chip: STM8S001J3 8-PIN SOIC-8 package. £8.50 ea. (Ebay) or 46p ea with MOQ of 10 (Digikey UK) but £2 ea with VAT & Shipping.
    2. STM8 Chips and Dev Board (DISCO) for STM8S00001J3: £8.50 from RS (next day delivery) + 3 programmable breadboardable uCs (£2 ea)
    3. STM8 Microcontroller board: STM8S103F3P6 ARM STM8: £6 for 2pc (£3ea), Prime delivery, or £1.40 ea
    4. STM8 USB programmer, £2.10

    PICaxe chips

    1. Overview (Wikipedia) | PICaxe description | Chips with the PICaxe bootloader | PicAxe language reference |
    2. PICaxe 08M2 (£4.50 or £4.50 option 2)| 14M2 | 15M2 | 18M2 £6 | List of Chips for purchase from Spiratronics UK

    Other small Microcontroller boards

    1. BBC Micro:bit – cool new computing platform with ARM Cortex-M0 for $18 (Sparkfun)
    2. Raspberry Pi Pico ($4)
    3. M5Stack platform for rapid development of IoT applications | About | Low Power Long Range (LoRa) and M5Stack | ESP32 prototyping M5Stack |

    Ultra Low Power & Low Cost uCs and Custom ASICs

    1. Microcontroller’s under $1 ea. (qty 100), by Jay Carlson
    2. EM Microelectronics: EM6580 (4-bits) | Custom ASICs (list) | EM6812 (8-bits) – ultra low power 8-bit uC
    3. CH552 8-bit microcontroller with USB connectivity for $1, and an example full tiny keypad for under $5
    4. GreenArrays-GA144 (Multi-core) – Chuck Moore’s latest chip, 144x F18A computers connected in a mesh network, programmable using ColorForth, ultra low power consumption (from 100nW consumption per idle node so 14uW for all nodes idle to 4mW running one node at top speed of 700Mips, to 650mW running all 144 nodes at top speed generating 100 total Gips), means dedicated circuits for sensor controls. Programming the GA-144 (video by Chuck Moore, 2013), GreenArrays site, $20/chip, $30 dev board, Breadboarding Example | For large-scale ubiquitous computing, the ultra-low power GA-144 multi-core controller with 144 individual controllers, invented by Chuck Moore, the father of Forth and of ultra-low power MISC (minimal instruction set computing) hardware designs, offer intriguing possibilities. The GA-144 has 144 independently programmable F18 microcontrollers, interconnected in a defined topology, on a single-die. Ultra-low power. Usage: Wherever there is a need for dedicated continuous real-time monitoring and control, instead of multiple discrete components and a lot of communication interconnects, this chip allows integration. Application: Piano-25 PCB (small scale, 3 dedicated controllers, 1 coordinating controller), smart sensored car (many dedicated controllers, 1 coordinating controller). Sort of like CAN bus in automotive control.
    5. #GreenArrays news & community on Twitter
    6. PIC Micro 8-bit: with UARTs in DIP-8 packages: PIC12F 1572 for £2.34/1822 for £2.73/1840 (£2.40). These are also PIC16F 15313/18313. I chose PIC12F1840 (7K program memory) Datasheets 1840
    7. TI MSP430: F2012IPW £6.40
  4. For high volume applications, the ultra-low cost category can be worth a look: there are the sub-30p reprogrammable ISP microcontrollers and the sub-10p one time programmable (OTP) microcontrollers. While these are really inexpensive and quite powerful, they are not easy for hobbyists to use, typically requiring specialized high voltage programming equipment, assembly language coding using proprietary toolchains with limited documentation. Examples: Padauk PMS150C example, full review);
  5. 3c microcontrollers: blog 1 e.g. PMS150C 8-bit MCU programmed with PDK5S-P-003, blog 2, blog 3

Ref: [Cravotta, 2010] 4-bitters
Ref: [Ebrahim, 2021] Programming Microcontrollers – Ultra Low Cost / Power Options

FPGAs and friends Overview (Wikipedia)

  1. PAL – Programmable Array Logic – MSI chip (medium scale integration) that allowed doing away with SSI (small scale integration) logic chips e.g. those in the 7400 series.
  2. PLA
  3. GAL – Generic (or Gate) Array Logic – improved upon PAL.
  4. CPLD – Complex Programmable Logic Device – Max V Kit (Altera)
  5. FPGA – Field Programmable Gate Array made by Alterra (acquired by Intel) and Xilinx
  6. Numato Labs Elbert v2 – $30 (entry level with Xilinx Spartan 3A FPGA), $20 shipping to UK
  7. Numato Labs Mimas v2 – $50 (mid level with Xilinx Spartan 6), $20 shipping to UK

    Not to be confused with

  8. PLC – Programmable Logic Controller – which are devices that do large scale monitoring. E.g. Atmel4809 can be an effective PLC.

F. Sensors and Communications

  1. Sensor Modules – £4.74 ea pc (MOQ2). or £26 for Kit of 37 pc.. Download the datasheets/tutorial (download, 50MB)
  2. Camera module, OmniVision CMOS camera modules: recommended with capable 32-bit uC e.g. ESP boards instead of relatively low processing power Atmega328s (Arduino). ArduCam CMOS camera interface on ASIC. Arducam Mega SPI interface requiring 6 pins: 2x I2C pins (sensor configuration) AND 4x SPI pins (camera commands, datastream), camera multiplexing possible using I2C and SPI interface IDs. 5MP has auto-focus. 2MP and 3MP has fixed-focus adjustable manually. 3.3cm square. 120-160mA when operational, c.50mA idle.
  3. GPS, £21 or £13
  4. ESC (Electronic Speed Controller board), £11.30 or £10 same day
  5. Pinion Engine Gear 5pc for £10, next day
  6. Motion Sensing / Human Intruder: use Passive Infrared or Dippler Microwave Radar
  7. KY-001 – Digital Temperature Sensor D18B20, £3.06
  8. KY-002 / SW-420 – Sensitive Vibration Switch (for less sensitive Knock sensor see KY-031): Lowest cost £1.31 ea, then £1.90, currently: 5pc for £5 (£1 ea). Or buy the components directly: SW-18010 sensor and KY-002 Arduino board
    • SW-18010 high sensitivity: lowest: 34p ea (MOQ10), currently: 80p ea (PiHut)
    • SW-18020 ordinary sensitivity: lowest: 31p ea (MOQ10), currently: £7.50 for 10 pc (75p ea.)
    • SW-18030 low sensitivity: 10pc for £7 (70p ea)
    • HDX-2 SW-420 normally closed, high sensitivity: lowest price: 17p ea (MOQ10), or for Waterproof components: 40p ea (MOQ10).
  9. KY-003 – Hall Magnetic Sensor, £1.70 ea., 5 for £3.00 (60p ea)
  10. KY-004 – Button Switch, 65p
  11. KY-005 – IR Transmitter, £1.70
  12. KY-006 – Passive speaker, £4.80
  13. KY-008 – Laser Transmitter, low-power, 650nm (red) works with 3V button cell battery, or 5V TTL from MCU. Lowest prices: £1.62 ea (Qty1) or 65p ea (MOQ10), or for laser head only without circuit boards 35p ea (MOQ10)
  14. combine with photoresistor (10x 90p ea.) with spectral peak at 540nm (GL5539),
    WARNING: use red laser protection goggles £10 (30 days delivery)

  15. KY-010 – Light Break Sensor, Photo-Interruptor, £9.70
  16. KY-012 – Active Buzzer, Lowest: £1.44 ea.
  17. KY-013 – Analog Temperature, £1.35
  18. KY-015 – Digital Temperature and Rel. Humidity, £3.00
  19. KY-017 – Mecury Switch £4.45 for 2pc (2.22 ea.)
  20. KY-018 – Photoresistor module (analog board): lowest: £1.38ea. Core component is the LDR (Light Dependent Resistor) aka Photoresistor (Darkness/Daylight Sensing), datasheet here: Assortment Kit: 6 value x 20pc ea. (120pc total) assortment kit, £3.20 (2.67p ea.), GL5506/16/28/37/39/49 (least sensitive) or individual values from GL5528, 20 for 69p (3.5p ea.) or GL5516, 20 for 77p (3.9p ea.) or GL5539, 88p for 20pc (4p ea.).
    Light sensitivity (in ohms) for common LDR photoresistors, from GL5506 (most sensitive to light, least resistance) to 5549 (most resistant to light)

    Light sensitivity (in ohms) for common LDR photoresistors, from GL5506 (most sensitive to light, least resistance) to 5549 (most resistant to light)

  21. Phototransistors
  22. Photodiodes
  23. KY-019 – 5V DC Relay module with Opto-Isolators rated up to 250VAC: 86p or £8 for 5x KY-019 relays (£1.60 ea.) w/ Prime Delivery or £5 for 3x KY-019 relays (£1.66 ea.) or £5.50 for single board with 4 channels
  24. UL Listed 120VAC Relay controllable with 5VDC, 10A switching, $125 ea.
  25. KY-020 – Tilt Switch, £2.00 or professional grade
  26. KY-021 – Mini Magnetic Reed Sensor, £1.70
  27. KY-022 – IR Receiver, £1.70, or 10pc for £2.05 (21p ea)
  28. KY-023 – Dual Axis Joystick, Lowest: £1 ea (qty1), 80p ea (MOQ5), or 60p ea (MOQ10)
  29. KY-024 – Linear Hall Effect Sensor, £2.10
  30. KY-025 – Large Magnetic Reed Switch, 2.60
  31. KY-026 – Flame Sensor, £5.40
  32. KY-027 – Magic Light Cup Sensor, 95p
  33. KY-028 – Digital Temperature Sensor, 2.60
  34. KY-029 – Bi-color LED (RG), £2.40
  35. KY-030 – Sound Detection Module, Lowest: £1.84 | MT02-02, 95DB-75DB (AT-SK-04, 6LUX) £1.81 pre-packaged sensor (to build yourself, get microphone and LM386 amplifier chip) |
  36. KY-037 – High Sensitivity (small mic) Sound Detection Module, Lowest: 80p, currently 92p (MOQ10)
  37. KY-038 – Standard Sensitivity Sound Detection Module, Lowest: 80p, currently £8 for 5 (£1.60 ea)
  38. Microphone: Lowest: £3 for 3pc. (£1 ea.), Mini Electret Microphone Condenser (Capacitor) with Pickup: £7.50 for 10pc w/ leads (75p ea, 6mm diameter x3.5mm thick, next day) Technical description of an electret circuit.
  39. Microphone + Amplifier: MAX4466, £9.60 for 5pc (£1.92 ea) or higher end MAX9814 £19 for 5pc (£3.80 ea) with automatic gain control
  40. KY-031 – Knock Sensor, £5.50 for 3pc.
  41. KY-032 – Obstacle Avoidance, £6.30 for 3pc.
  42. KY-033 – Tracing Line Hunter, £1.40
  43. KY-035 – Analog Hall Magnetic Sensor
  44. KY-036 – Metal / Human body touch sensor, £9
  45. KY-039 – Heartbeat Sensor, £2.79. ea, or £5.50 for 3pcs. (£1.80 ea.) or £1.88 singly (heart shaped) or £1.86 singly (rectangular).
  46. instructions Uses Infrared emitter and receiver.
  47. KS-039 – Real-Time Clock DS3231 or AT24C32, I2C: Lowest £1.43 ea
  48. KY-040 – Rotary Encoder/Encoder module, £6 for 5pc no knobs (£1.20 ea) next day, £10.85 for 8pc w/ knobs (£1.35 ea), next day, £8.85 for 6pc w/ knobs (£1.50 ea) next day | Useful for: parameter selection (user interface), fine-grained control of many options (more than a switch would provide), does not require a keypad for entering multiple IDs. | References: Discussion & Implementation
  49. KS-007 – Rotary Encoder, 6mm shaft, £2.90
  50. KS-040 – Smoke Sensor, lowest: £2.17
  51. KY-041 – Big 12mm Button Module, £2.70
  52. KS-041 – Alcohol Sensor, Breathalyzer, £4.50
  53. KS-042 – Methane Sensor, £4.60
  54. KY-043 – Passive Buzzer
  55. KS-044 – Propane Butane LPG Combustible Gas Sensor, £4.50
  56. KS-045 – Carbon Monoxide Sensor, £4.60
  57. KY-046 – LDR (Light Dependent Resistor)
  58. KS-046 – Hydrogen Gas Sensor, £4.80
  59. KY-047 – Thermistor Temperature
  60. KS-047 – Pollution Sensor, £4.60
  61. KS-048 – Rainwater, Water Depth Sensor £3.30
  62. KS-049 – Moisture Detector, £3.30
  63. KY-050 – Ultrasound Ranging Sensor, HC-SR04 £4, or £9 for 5 (£1.80 ea), or £10 for 5 (£2 ea) w/ mounting bracket

  64. PIR Motion Sensor – HC-SR501 fully configurable, large lens – Design/Online Reference – Lowest Price: 80p ea (MOQ5), £1.10ea (MOQ10), Currently: £13 for 10pc (£1.30ea, next day) or £12.70 for 10pc (£1.27ea), 1 wk, or £7.50 for 5pc (£1.50 ea), 1wk, or HC-SR501, £2.45 ea, or £1.10 ea when purchasing 10 (£11) same day. Powered by BISS0001 dedicated PIR controller ASIC, £1.20 qty 1 DIP16
  65. PIR Sensor – MH-SR602 Techtonics Mini Motion Sensor – £8 for 5pc (£1.60 ea, next day) | Datasheet online
  66. PIR Sensor – AMS312 – £9 for 10pc (90p ea, 3 weeks), or £8.50 for 5pc (£1.70ea, next day) | Datasheet online
  67. PIR Sensor – KS-052, 3-12V mushroom form factor, £2.86 ea

    HC-SR312 2.7-12V mushroom factor, smaller lens, non-configurable, 5x for £8 (£1.60 ea) next day, Susceptible to false triggering

    HC-SR505 mini lens, reduced range, non-configurable, 5pc for £9 (£1.80 ea)

    Notes: Conversion to run on 3V/3.3V for use with ESP8266 wifi, Comparison of variations

    The directions for turning the potentiometers are when they viewed from the top, i.e. facing you and ready to be turned. Critical one to adjust is the timing delay – maximum CCW turn sets to 3 seconds delay.

  68. Non-Contact Infrared Thermometer, £13
  69. AMG8833 – Infrared Thermal imaging Camera available as a component to be integrated as a sensor, £22
  70. Camera product with screen on top of the AMG8833 infrared thermal imaging camera sensor, £30
  71. KS-053 – Colour Sensor
  72. KS-060 – 4×4 Matrix Micro Switch Keypad, (used to be £2.40ea ebay) |5 pcs for £7 (£1.40 ea) next day (no hardware debounce). 4×4 matrix keypad usage: connect 8 pins to uC, treat 4 as transmit pins (output) and 4 as receive pins (input), with a scan/interrogate logic to determine which key is pressed — see 3iSensor.fs and 3iSensor.avr code. Because the keypad must be driven using both Tx and Rx, an SPI hack could simplify the interface.
  73. K62103BS – MODAL KEYPAD: 4×5 Matrix (16-key + 4 mode selection keys) keypad. HIGH POTENTIAL Using each as a bank of commands gives 64(=16×4) commands. Using each as a binary selector gives 256 (=16*16) commands. Since it has a bank of 8 LEDs, could be used as a high speed 16-bit hex input device: keypad inputs hex a nybble at a time, and modes which nybble and display.
    £3 ebay or £3.50 ebay

  74. 4 Direction Keypad with 3 buttons £2.50 ebay
  75. 5 Direction Joystick Keypad with 2 buttons £3.00 ebay
  76. TTP229 4×4 capacitative touchpad £4.50 ea.
  77. 4×4 Matrix Membrane Keypad, 5 pcs for £6 (£1.25 ea) same day, £2.39 (picclick)
  78. KS-088 – IR Remote Control and Receiver, £4.60
  79. Eye Blink Sensor using InfraRed
  80. KS-097 – Bluetooth Serial for Arduino, £6.90ea, 12 EUR, or 2pc. for £10 (£5 ea, next day), KS-393 Bluetooth/WiFI Choices for Bluetooth: ESP32 (and Android smartphone), HC-06 Bluetooth module. Bluetooth uses the standard serial protocol. Setup. DSD Tech Blue Tooth specialists. Bluetooth primer: HC-05 (master/slave mode, Bluetooth 2.0), HC-06 (slave mode only, Bluetooth 2.0), and WF-05 (WittyFox) (dual mode, but Bluetooth 5.2, so can connect to smartphones and laptops). WF-05, £5 ea for HC-05, HC-06, and JDY-31
  81. KY-098 – Ambient Light Sensor, £3.60
  82. KS-143 – Bluetooth XBee, £7.90
  83. KS-148 – Ethernet Breakout, £7.30
  84. KS-167 – Weight Sensor
  85. KS-168 – Fan Motor, £4.60
  86. KS-186 – Current Sensor Module
  87. KS-196 – Optical Dust / Smoke Sensor, £12.30
  88. KS-203 – Steam Water Vapor Detection, £3.30
  89. KS-204 – UV Sensor Module, £5.50
  90. KS-272 – Ceramic Piezo Vibration Sensor, £5.70
  91. KS-279 – Slide potentiometer, £7.90
  92. KS-280 – Breadboard Mini Power Supp
  93. Mini-Voltage Sensor, 4.30
  94. Barometric Pressure, Temperature, Altitude, £7
  95. Weight sensor (24-bits), £8 for 6pc (£1.50 ea)
  96. Gyroscope/Accelerometer/Magnetic, £9 for 2pc (£4.50 ea)
  97. Temperature, Barometric Presssure, Altitude, Humidity, £17
  98. Gas Sensor Module, £20 for 9 (2.11 ea)
  99. 16×2 I2C LCD Display, £4.40
  100. Color Sensor Module, £5.50
  101. Luminosity Sensor TSL2561, GY-2561, £1.73
  102. Gesture Sensor / Proximity Sensor: £3.40 using luminosity sensor
  103. GPS (excl. battery): Neo-6M-GPS-Module-GY-GPS6MV2, £4.28
  104. Gyroscope/Accelerometer: 9DOF-MPU-9150-3-Axis-Gyroscope-Accelerometer-Magnetic-Field, 3-axis, £8.79
  105. Light Intensity Sensor: LM393-Light-Sensor-Module-3-3-5V, 29p ea (MOQ5)
  106. Barometric Pressure BMP280 (hw-611 e/p 280), I2C interface: 82p
  107. Traffic Light module: £15 for 30pc (50p ea, 3 wks), or £5 for 5pc (£1 ea, 1 wk) or £6 for 6pc (£1 ea, next day), or sj-3wgj-h6md Or: KS0310 model. Or real traffic lights. Reference 1, Reference 2 Note: The LEDs are nice and big (10mm?) and the module looks good. However, the green LED is much dimmer than the others. In interior light, the green LED is faint when lit; in daylight, it’s practically undetectable. This due to the designer applying the same surface-mounted 330R current-limiting resistor to each LED, instead of using a lower value for green. The workaround is to solder a 33R resistor across the terminals of the surface-mounted 330R resistor, creating a parallel bypass leg with lower resistance, hence providing the green LED with higher voltage.

    To increase the brightness of the Green LED, solder a 33-ohm resistor across the surface-mount 330R resistor to create a lower-resistance, higher-voltage/current parallel path.

  108. Ultrasonic Sensor: Lowest: 59p ea, currently: £4 ea.
  109. Soil Humidity/Dryness Sensor/Hygrometer: 51p ea. (MOQ5), or £1.20 ea.
  110. Full automated irrigation system – £74
  111. Magnetic Reed Switch / Magnetic Induction Switch (Normally Open) Lowest Price: 17p (MOQ10), Currently: £2.40 for 10pc (24p ea), or 22p ea for 40x, 0.5A current or £2.45 for 10pc (25p ea), or 23p ea.)

    Video: How to make an N/O reed switch and convert to N/C?

  112. NO/NC, £12 for 4pc (£3 ea), door alarm kit, magnetic reed switch sensor or £9 for 10pc NC only (90p ea), pre-wired with 25cm cable,
  113. Tilt Switch / Ball Sensor: SW-100 (KY-020 board), 100 pc. for $9.50 (9.5c ea.) or SW-200D, 10pc. for £1 (10p ea.), max 12V input
  114. Photo Interruptor (Light Blocking Sensor): Board, £1.03 or Slotted Optical Switch, £2.49 for 10pc (25p ea.)
  115. Temperature Sensor: Analog board KY-013, £1.35 or Digital board KY-028, £2.75
  116. Capacitative Touch Switch: TTP223B, 5x for £1.28 (27p ea.)
  117. Metal/Human Touch Sensor: KY-036 board, £3
  118. Linear Hall Effect Sensor: Board, £3 or sensors £1.60 for 10pc (16p ea)
  119. Flame Sensor: £2.43 (red board) or 78p (blue board, MH Sensor Series, Flying Fish)
  120. Serial Communications
    1. DB9 female / RS232 to TTL: £1.61 for 1pc, fully assembled, with 4pin cable, or £1.17 as above or 5 pc for £4.00 (80p ea.)
    2. Cables: USB to DB9 Male73p
    3. Gender change adapters: DB9 F/F, 25p; USB A F/F, £2.22 (Prime) this is a cross-over coupler (the top pin goes to the bottom, and so on)
    4. USB / RS232 to TTL: Lowest: £1.18 for 1pc, Now: £3 for 1, or £1.10 for integrated cable with 4 TTL leads
    5. USB C to USB: 4pc for £2 (50p ea)

    References:

    Remote Control (RC) and Radio Frequency (RF) Communications

    1. [tried] 4-channel wireless remote control modules, QIACHIP 433 MHz Radio Frequency (RF) Tx/Rx pair, TX-118S-4 transmitter, receiver with 1527 learning code, 3V-24VDC operation 3 pairs for £9 next day

      Pinouts for 433MHz RF transmitter and receiver pair, £3 ea. pair

    2. STX882 433 MHz Rx/Tx pair for £8
    3. 27MHz 4-channel RC Remote Control, 4 pc. for £10 (£2.50 ea), or £6 controller, 40 MHz 2-channel remote control, £2.50. Discussion on pros/cons of 27 MHz/40MHz/2.4 GHz…
    4. How Remote Control RF radio works…
    5. 27MHz 5CH controller (5 buttons) + receiver + antennae, (XN-AR11R-V4) £5.71 delivery in 10 days, 4CH Rx/TX boards £2.48 3 weeks, £5 option, £8 for controller with 2 button joysticks
    6. 33 MHz EV 1527 TX/Rx board pair for £2.50
    7. 40MHz 4CH Rx/TX board components £2.54 3 weeks
    8. DO NOT BUY THIS 433 MHz RF transmitter/receiver – 5 pc for £6 (£1.20 ea) next day, Receiver 1527 module for £4.30, Transmitter EV1527 module, 7 pc for £7 Tx/Rx pair DO NOT BUY THESE – many reviews on incomplete or poorly made boards being sold by many sellers.
    9. 2.4 GHz controller £10, or 2.4 GHz 4CH controller £35, or £11, 4CH £7 ebay
    10. 2.4GHz with antenna for £1.19 or 315 MHz x 5 pc for £2.65 (53p ea.) or 2.4GHz ESP system or 8266 WiFi Module, £8 for 4pc (£2 ea);
    11. RF Sensors, can detect fluid flows and dynamics of objects: How RF sensors work. Example: VIPER field disturbance sensor
    12. RFID (Radio Frequency IDentification) / NFC (Near Field Communications)
      1. RFID Reader / Writers
        1. Passive LF (125kHz) £28 or just the module £8; up to 1m, £69, 125kHz Sparkfun Kit for $52, 125kHz ID-20LA Innovations, £28.07
        2. Passive HF (13.56MHz, RFID/NFC), Reads @ max 20mm: (1) RC-522 Module + S50 Card & KeyFob £1.94 or £4 (with chip manuals) (instructable here); or KS-204 at £5.19 (2) Reads @ max 50mm for UNO R3 (PN532), £13
        3. Passive UHF (860-925 MHz)
          1. Chip (IC): ThingMagic M6E-NANO (surface mount) $125 with multi-tag read capability. (ThingMagic was a brand of Trimble Navigation, makers of GPS systems.) Needs a carrier board to use it..

            Based on Atmel SAMD21 32-bit ARM microprocessor. Note that the M6E-NANO is the low end of the ThingMagic M6 (Mercury 6) product line (watch video). At the higher end is a 31.5dBm, 1.5W module capable of longer read distances and up to 750 simultaneous tag reads/second.

          2. UHF RFID Reader Carrier Board: SparkFun SEN-14066 based on ThingMagic M6E-NANO, $225 with excellentsetup documentation or £232 from Amazon.co.uk or £212 from CoolComponents.

            Key specs: (a) simultaneous (multi) tag reader (max 150-200 tags/second), (b) can write to tags, (c) max read distance is 16ft (4.9m) with adjustable power output 0 to 27 dBm, (d) is an Arduino UNO shield, i.e. compatible wwith Arduino form factor/pinouts, and the Arduino toolset/ecosystem/coding platform/open-source libraries, (e) reads standard Gen2 UHF RFID tags, (f) 5V operation, (g) UART 5V for TTL serial communication (9600 to 115200 baud), (h) serial selection switch toggling between HW serial (Rx/Tx on pins 0/1) to SW serial (Rx/Tx on pins 2/3), (i) firmware compatibility with Jadak’s ThingMagic UHF RFID line including 2- and 4-port reader modules< and specalised or custom-designed antennas, (j) USB to PC connection through FTDI breakout board to use Jadak’s URA (Universal Reader Application) software for easier exploration of all ThingMagic features and configurations.

            The Sparkfun board works, but is of medium difficulty to setup: requires a soldering iron, FTDI serial to USB breakout board to test using PC uRA software, R3 stackable pin headers for use as UNO shield, external antenna for long range reading, 2 auxilliary antenna cables to enable connection , and Sparkfun Redboard UNO compatible main board for direct / headless connection without collision of the integrated antenna with UNO components. Have not been able to get it working headless with nano because of the incompatbile pin to pin connection and the difficulty of high speed (115k baud) serial communications over jumper wires.

          3. Alternatively: AtlasRFIDstore, $263 or JieTong, £101 (incl. £21 delivery), a small size short range UHF tag reader w/ UART interface, or 3m-6m reader with 8dbi integrated long range antenna, £177, 10-1000mm, £145; 10-500mm, £140

            References: (1) Hookup Guide (2) Video illustrating usage

      2. Tags: Passive long range UHF tag: Alien H3, 20pc for £8, 1-6m depending on reader, Monza Tag, 20pc for £9
      3. Passive UHF RFID Laundry Tag, 5pc for £11, or UHF passive laundry tag $1 ea, machine washable.
      4. Antennas: Passive Long Range *UHF RFID External Antenna: 860-930MHz:
        1. WRL-14131 6dBi gain, linear polarization (for reading fixed orientation tags) RP-TNC (reverse polarity) female connector: $35 (Sparkfun) or £48 (CoolComponents UK) or 1m-4m, £60 Antenna Only 6dbi gain (Sparkfun);
        2. MTI Wireless, MTI-262041, 85*x85* beamwidth, 5.0dBic gain (circular, with circular polarisation), $565
        3. MTI Wireless MTI-242043, $140, 8.5dBic gain (circular), with circular polarisation, 65*x65* beamwidth, pre-certified by FCC for use with M6E-NANO, or MT-262062, or MT008S08LH, 65*x65*, 9.0dBic gain (circular), or MT009S08LH for , or MT-262006, 63*x63*, 9dBi
        4. MT-243005 Dual polarization 120* x 16* beamwidth, 3dBi gain, 10W, 1.2m x 0.5m base station antenna for $1800, or 263004 Sector Antennas, $860-1360
        5. MTI Wireless, MT-263018, 65*x40* beamwidth, 10dBic gain, 6W
        6. MTI Wireless MT-263020, $460 (US price) (11dBic circular gain / 8dBi linear) with circular polarisation, 63* x 30* beamwidth (elevation x azimuth), highest gain antenna already certified by FCC for use with M6E-NANO
        7. Extronics IANT217 Omni-directional (no predictable orientation) UHF antenna, 7dBi gain;
        8. 1m-4m, £90 Antenna Only 6dbi gain, circular polarization
        9. Custom Design, Wide Selection: MTI Wireless Edge selector, 32 UHF MTI Antennas (list), 865-928 MHz, 8353 antennas with parametric search (Everything RF), 10 RFID circular UHF antennas (all directional); 900MHz Patch, Directional, Omni, Sector, and Grid; 243 RFID Antennas from Arcadian; 23 RFID Reader Antennas
      5. Antenna Interface cables
        (note – antenna cables have a confusing mix of gender and polarity — see this guide)

        1. *RP-TNC male to RP-SMA female cable: £15.12 Amazon Prime or £14.40 from 4GLTE.eu
        2. *RP-TNC male to RP-TNC female coaxial extension cable: 6′ for $16, 15′ for $19
        3. *RP-SMA male to U.FL cable: £18.52 Amazon Prime or £16.80 from 4GLTE.eu (WiFi nation)
        4. RP-SMA female to U.FL Sparkfun WRL-00662 or £3 in UK and
        5. U.FL to SMA £3.50 in UK
      6. Data Interface Boards: FTDI interface (serial to USB): £15 (Amazon), or £15 (Cool Components) requires USB mini (not micro) B cable.
      7. Universal Reader Assistant (URA) software

        RFID Notes & References

          RFID systems.

        • The simplest RFID system consists of three parts: Reader + Antenna (for radio transmission and Tags (receiving antennas that backscatter ID information).
        • The tags can be passive (powered by the interrogation signal from the reader), battery-assisted (semi-)passive, or active (self-powered).
        • System is classified by radio frequency used — readers, antennas and tags have to match:
          • low frequency (LF) less than 132 kHz (40€-70€),
          • high frequency (HF) 13.56MHz (40€-1000€),
          • near field communications (NFC) which is a subset of HF that additionally features encrypted data exchange (e.g. bank cards), and
          • ultra-high frequency (UHF) 860-960MHz (140€-2000€)
        • Readers have different levels of integration: chip, modular, or finished. Finished readers are off-the-shelf ready to operate; modular readers are components that are lower cost, customizeable and can be integrated into an engineering product solution. Modular readers can be an individual chip, or a development board which onto which the chip is integrated.
        • Ranges: passives tags have a range of 1-7m depending on tag size and reader power; battery-assisted passives: 50+m (150+ft)
        • Encoding data into RFID tags
        • RFID Tag specification, Gen2 Air Interface Protocol

          Antenna Concepts

        • Excellent explanation (Mobile Mark Co.): antenna theory basics made accessible
        • Antennas are classified by various parameters, and selection is critical for a desired application
          • Frequency: higher frequency means longer range, higher power, smaller wavelength hence greater detection, better detection grain. UHF is 865 to 928 MHz.
          • Polarization: describes the geometry of the radiated fields produced by the antenna. A linear polarization means that the electric field oscillates in a plane, and is constant in the direction of travel. A tag whose orientation is not aligned with the polarization suffers polarization loss in its backscatter. Cell phone antennas are often linearly polarized, which is why signal quality varies point to point. Circular polarization means that the electric field oscillates radially, so a tag will reflect regardless of its orientation. GPS satellites are RHCP for this reason.
          • RHCP and LHCP (right- and left-hand circular polarisation) – no difference, just match transmitter and receiver for maximum signal strength and least interference
          • Amplitude: signal strength
          • Radiation pattern: the geometry of the wave pattern, omni-direction or directional, based on angles vs. various amplitude levels, measured azimuthal in the plane and elevation in the z direction
          • Wavelength & detection grain: related to the wavelength (e.g. UHF is 860-930MHz [cycles/sec], so each wave travels for 1.075×10^-9 seconds. Since light travels at 3×10^8 m/s (300M meters per second), the wavelength [distance between waves] is 32.2 cm to 34.5 cm (=300/930 and 300/860)
          • Phase: relates to the parts of the wave, and determines potential constructive or destructive interference. For UHF, half wavelength is about 16-17cm — this is the destructive point (minimum energy). Quarter wavelength is about 4-5cm — so could put a ground plane (reflective metal sheet) at this spacing to enhance the signal.
          • VSWR (Voltage Standing Wave Ratio): smaller is better

          Examples

        • White Papers. Guide to UHF tags (PDF)
        • Battery assisted passives (BAPs) – case study: Vaillant boilers
        • The battery in BAP tags are usually not replaceable, and once it dies out these tags need to be replaced.
        • Hybrid passive/BAPs for pervasive sensing: “RFID is the cheapest, lowest-power RF communication protocol currently out there. When generic RFID chips can be deployed to sense the real world through tricks in the tag, pervasive sensing can become reality.” (Sarma, source)
        • Other case studies

  121. Electric Door Lock / Door Solenoid: 9mm stroke / 15N force, 12VDC, 16W (1.3A) £11.10 or JF-S1670DL, 10mm stroke / 40N force, 12VDC, 2A, 24W, £13.23 or JF-1264B 55N, £20, or JF-1250B, 60N, £21

    Strike locks are normally closed and use power to draw back the strike mechanism (stroke). Need enough pull in force to counter friction/resistance on the bolt. Lots of choice here (Locks online) and The Solenoid Company / Impulse Automation

G. Motors

Start here for everything you need to work with, fabricate, mount to, and mount on motors! ITP Fabrication

Next here for inspiration on Engineering Design of small autonomous motorized robots built by students in 13 weeks as part of ELEC 201 Intro to Engineering Design, Rice University, Instructor: James F. Young and Course 6.270 Autonomous Robot Competition, MIT, Instructor: Fred Martin and Randy Sargent

Selecting a motor: 4 types of motors to choose from: (1) can DC, (2) geared DC, (3) servo DC, (4) stepper motor.

Mounting a motor: custom 90* assembly for motor and worm gear £4.80 (spiratronics), dc motor base mounting bracket (20mm), 25 pc. for £7 (28p ea), mounting hub or £8.50 (34p ea) Amazon, or 10pc for £4.86 (48p ea), or alternate screw type £2.20 ea

Attaching to a motor drive shaft: ideas: hot glue, drill bit/press fit, shaft coupler, hose tubing, heat shrink tubing, coupler to universal drill bit coupler, end of plastic/wood rod/dowel, drill & tap metal, weld, pin, solder, clamp, clamping collar, adapting bushing, terminal blocks (150 for £7, or 5p ea)

Mounting a motor:

Controlling a motor (feedback loop):

Stall/Free current, Stall/Free torque.

Gearing down a motor to create torque – torque increases linearly with gearing ratio

Making things move: Gears & Propellers

Uses for small motors: hovercraft, propeller cars, helicopters, etc.

Powering Motors – I use CR123 3V lithium batteries. These are cheap, long laster, and provide steady voltage over their life. They also hold their power up to 10 years (per spec, not tested of course).

Wheels / Moment Arms / Propellers

  1. Wheels and Axles – 50 wheels (42mm) and 25 axles (2mm shft) for £9.59 (38p per axle) Note: can carefully expand shaft diameter to 3mm using two steps, first expand to 2.5mm then to 3.0mm.
  2. Eye Caster Wheel (cow eye/bull eye) – 5pc. for £5.62 (£1.12 ea) ebay, or 5pc. for £6.20 (£1.24 ea) ebay, or £1.72, £1.98, Lego Caster Ball (£6), Lego Caster Wheel on a rotating platform using “landing gear wheel” (#2415, 4pc for £2.75, 67p ea.) attached to swivel platform (“turntable”) (#3679,3680, 10pc. for £2.90, 29p ea.)

    Simple Lego caster wheel made from a single “landing gear wheel” attached to a swivel platform (“turntable”) which is in turn attached to the baseboard with a 2×2 brick.

  3. Propellers – Drone flight and propeller selection, Modeling Thrust FancyWhoop 3-bladed props, 16pc for £9 (56p ea) next day 2.5″ for Emax BabyHawk Race Pro (video) using F15 1106 6000KV motor £16ea. Understanding quadcopter motors. Flight forces calculator: weight, lift, thrust, drag (motocalc.com) DRONE KNOWLEDGE

Motors

DC Stepper Motors:

  1. 28BYJ-48 5V DC Stepper: 5 pc for £5.83 (£1.17 ea.) ebay
  2. Motor + ULN2003 driver board: Available singly @ £1.32 for motor + driver board, or 5 pack at £7 (£1.40 ea.), or 5 motors + 1 driver board for £11 (2.20 ea) next day or 5 pack + 10pin male-female jumper wires, £14 (£2.80 ea.)
  3. ULN2003A IC chips – this is all you need to drive the motors – you don’t need a driver PCB as the Darlington Arrays are very straightforward to hook up – the chip is itself the interface. Note – power goes to pin 9, ground to pin 8., 20 pc.for £4.80 (24p ea.) 1 month, 10 pc. for £3.80 (38p ea.) 4 days, 10 pc. for £3.40 (34p ea.) 4 days, 10 pc. for £2.48 (25p ea.) 1 month
  4. ULN2003 motor driver surface mount PCB with surface mount LEDs (note, these are good for test but not production, as they consume additional power and are always on). 5x for £6.40 (£1.30 ea) next day

    Shaft 5mmx3mm, motor wire red=power, a step is a signal to the motor, max gear ratio is 1:64 (1 revolution = 64 steps) when driven in half step mode, so half step angle is 5.625 degrees (=360/64). Micro-step mode has 64 micro-steps per step 1 revolution = 4096 microsteps (=64×64) of 0.088 degrees each (=360/4096), 5V rated, noise < 35dB, slower rotational speed means higher torque, can do up to 25 rpm, at 4 rpm can open heavy curtains. Tip1: Put a relay between the power pins to ensure that software can cut power to the motor (not spinning does not mean unpowered). Tip2: bolt motor to copper plate as heat sink to dissipate heat buildup.

    28BYJ48 Step Motor cheat sheet.
    4 phase 5V stepper motor with internal gearbox providing max 4076 micro-steps per revolution in half step drive mode. (2038 steps in half power wave drive mode)


    Driving 28BYJ stepper motors via Darlington arrays ULN2003A IC which provide 500mA max current each (2A max total, 10W drive at 5V).

  5. Micro steppers: Mini Micro (smaller than a coin), 2 phase, 4 step, 3V microstepper 10 pc for £5.22 (52p ea.) or 10x 2 phase 4-wire microstepper motors for £10.90 (£1.10 ea.)
  6. Attachments 5mm x 3mm shaft: (1) Polymorph coupler to 2mm axle, (2) 5mm drill bit, (3) 5mm to 3mm shaft coupler £3.83, 5x multi-couplers max to 5mm,for £8 (£1.60 ea.) (4) Variable angle 5mm to 5mm coupler with set screws, 5 for £10 (£2 ea.), (5) plastic gear adapter, 2mm to 5x3mm,
  7. NEMA17 high-torque stepper motors

DC Motors:

    Small DC Motors, 12 kinds, for £8.40 (70p ea.)

  1. Micro 130 DC motor – no gearbox, high speed (9500rpm)/low torque, without gearbox good for experiments and propellars (datasheet), only good for propeller without gearboxDC 3-6V 16.5k rpm motor: 10pc for £4.50 (45p ea.) ebay or 10pc for £10.50 (£1.05 ea.), or 6x kit with motors and motor brackets (holders), £11
  2. RF 300 DC motor – without gearbox, low torque, good for propellers and spin launchers 1.5V-6V, 1700-7300rpm, 50p ea.

    Using Gearboxes: Warning: when using a motor without any other speed/current control mechanisms you will need a high current resistor, capable of handling up to 2A, i.e. dissipating up to 1-10W of energy, as the motor itself is low resistance and the shaft will typically spin >2K RPM with little torque strength which is not useful for most applications. A gearbox slows down the RPMs and delivers stronger torque:
    Article1, Article2, Article3, Article4, Article5

Geared Motors (with integrated Reducing Gearboxes)- 3mm shaft (except as indicated):

  1. 2x motor drivers, 4x geared motors, and 4x wheels – £15 These are large wheels, great for a robotic platform with differential steering. Enough for 2 such robotic platforms (need 4 caster wheels)
  2. Micro Mini N20 motor 3V-6V, ebay £2 ea. with PH 2.0 female connector 55rpm [tried 8x]
  3. GA-12 N20 motor ebay, £2.25ea (MOQ 8x), 30-2000 rpm, tried 2x ea. in 30rpm/3V, 70rpm/3V, 150rpm/3V and 30rpm/6V flavors
  4. Geared DC motor + wheels, 4pc for £7.20 (£1.80ea), 6pc for £14 (£2.33 ea) 3 weeks, 90/200 rpm at 3/6V.
  5. Geared DC motors + wheels + L298 dual axis PWM motor driver, 2pc. for £10 (£5ea) next day, 4pc. for £15 (£3.75ea) next day
  6. 4x Geared DC Motors – £10 next day (£2.50 ea.)
  7. Motor Driver chips – Overview of all choices
  8. L9110 chip: £2
  9. L298 chip: H-Bridge dual channel DC Motor Driver (with built-in polarity reversal) Instructions (Sparkfun)
  10. L298 boards: 5 pc. for £11 (£2.20 ea) 3 day, 5pc for £11.50 (£2.30 ea.), or singly at £2.50 ea
  11. 5 RPM (full rotation once every 12 seconds), £8.65 next day;
  12. 10 RPM (full rotation every 6 seconds) £8.90 next day;
  13. 20 RPM (full rotation every 3 seconds);
  14. 40 RPM £6 next day
  15. 100 RPM, £8 with mount next day
  16. 130RPM Sparkfun, micro gearmotor
  17. 600RPM £4.60 next day
  18. 12V motors 5-700 RPM sealed, 12V motors 5-700 RPM £3.50 30-days
  19. 5mm shaft – 18 RPM £3 (30days);
  20. Decent torque, but 30rpm is too slow for a car. [tried]6V 30 RPM (full rotation every 2 seconds) £6.30 next day open construction, £7 next day, £9.79 next day with long threaded screw shaft
  21. Dustproof design: 60-600 RPM, 6V 100 RPM £3.10 (30 days)- tried, too little torque

DC Servo Motors:

  1. MicroServo SG90 (torque 1kg/cm, plastic gears) Best price was: 10pc for £13 (£1.30 ea), 5pc for £9 (£1.80 ea), 5pc for £10 (£2.00 ea), Datasheet/connections. Not recommended for general use.
  2. MicroServo MG90S (torque 2kg/cm), or 5pc for £12 (£2.40 ea), or 10pc for £24 (£2.40 ea) or 10pc for £27 (£2.70ea) or 5pc for £18 (£3.60ea)
  3. MicroServo MG996R (torque 13kg/cm) or MG995, 10pc for £36 (3.60ea) or 4pc for £18 (£4.50ea) or 4pc for £19 (£4.80ea)
  4. DMS15 (torque 15kg/cm) or LD-3015MG
  5. LDX-227 (torque 17kg/cm), £17
  6. SR-6120MG (torque 20kg/cm) or LD-220MG or LD-27MG or LD-20MG or A202-81 £11
  7. A202-81
  8. Servo Motor PWM Driver Board: PCA9685 board, 16-channel, I2C, free-running with built-in clock £5 next day, or £4.50 3 weeks

Robotic Platforms

  1. 6 DOF Robotic Arm £140 or $179 or £190

    6 Degrees of Freedom – Robotic Arm £140, with 6-channel wireless bluetooth controller for each motor separately

  2. Hydraulic Robotic Hand £120

    Hydraulic Robotic Hand

  3. DC Motor PWM Speed Controller: 3-35VDC, mini with 6mm knob, £1.43
  4. Electric gearbox
    one
    two
    three
    four

  5. Steering rods/mechanisms:
    one
    two
    three

  6. Steering Theory
  7. Timing Belt Toothed Pulley
  8. Motorized Wheel
    one
    two

  9. Chassis & Robotic Car Kit
    one
    two

  10. Robotic Devices & STEM toys
    one
    two
    three
    four
    five
    six

  11. Robotic Arm
    one
    two
    three
    four
    five
    six
    seven

  12. High Performance RC Cars
    wall climber £11
    Lambourghini Black £13
    Lambourghini + Batteries £15
    Hi Speed £15

  13. Example wooden toy RC motor car driven by simple pulley, forward/backward only, 27MHz remote control and antenna, £4.52 (ebay) or £13 on Amazon (with better pictures for helping with assembly)
  14. Steerable remote control car, 27 or 40 MHz control frequency, £7 ea.

Motor Couplers
A coupler allows connecting motor shaft to something else. A shaft of 5mm x 3mm requires a 5mm coupler. The set screws are used against the 3mm side to keep the coupler in place.

  1. 2.3mm/3mm to 5mm shaft coupler (for wheel axles): 3mm for 65p (best price anywhere), 2.3mm for 99p (ebay)

Gears, Gearboxes, and Pulleys

Basic Machines / Mechanical systems: there are SIX fundamental mechanisms for automata: (1) Pulleys, (2) Crankshaft, (3) Camshaft, (4) Gears, (5) Ratchet, (6) Lever, (7) Screw (converts rotational to linear motion).
Motor driver to screw for precise linear alignment – 5pc. for £7.81, 10pc for £18 (£1.80 ea.)

  • Mounting Platform: 2x screws, platform (wood or copper plate for heat dissipation), DC motor bracker
  • What are you pulling?
    1. Gear & Pulley Kit, 2mm aperture (shaft diameter), 78 pieces for £3.85 Simple & Compound Gears, Sprockets, Simple & Compound Pulleys, Axles, Bevelled Gears. 58 pc. for £3.10, 2-3mm aperture, 64 pc. for £3.51, 2-3mm aperture
    2. Steel Axles/Rods: 2mm diameter 10x 100m for 5.26
    3. Pulleys: Reducing slippage in pulley systems (article 1): (1) more tension (smaller belt, pulley wheels further away), (2) more friction (sandpaper pulley surface), (3) gear mechanism, (e.g timing belt GT2 pulley, wheel, and belt, closed loop, for £16), (4) run the pulley faster. Belt slippage theory
      1. Assorted plastic pulleys (Spiratronics), 15p ea., from 10mm to 30mm, for 2mm shafts to 3.2mm shafts
      2. 4 pack of mixed pulley sizes to illustrate pulley ratio, £3.90 (Amazon), or direct from Spiratronics
      3. 2mm shaft, 6mm dia, axle drive pulley: 50pc for £2.29 (4p ea.) or 20pc for £4.60 (23p ea.) next day
      4. 2mm shaft, 10mm dia: 10pc. for £1.09 (11p ea.) Spiratronics
      5. 2mm shaft, 17mm diameter: 30 pc. for £4 (13p ea.) next day or 30pc. for £2.40 (8pc ea), or 100pc for £6.20 (6.2p ea.)
      6. 4mm shaft, 25mm dia: 10 for £5.80 (58p ea.),
      7. 10pc for £2.50 (25p ea.), 5mm D-hole shaft 36mm dia
    4. Pulley bands Drive belt theory (Wiki) Belt drives Basic Machines theory
      1. Lego Rubber Bands – Round cross section: White 15mm 5 pc for £3 (60p ea), Red 25mm 5 pc for £3.30 (66p ea), Yellow 33mm 5pc for £4 (80p ea)
      2. 100mm unstretched normal rubber bands for 2mm pulley (stretched 400mm) 100pc for £5 (5p each)
    5. Wooden rods/dowels/bars, 5mm rod can be drilled with 2.3mm drill bit to hold a 2mm axle comfortably:
      1. 5cm balsa wood square: 10 for £1.80 (18p ea.)
      2. 6cm pine wood squares: 50 for £4 (8p ea.)
      3. 7cm balsa wood square: 30pc for £3.67 (4p ea.)
      4. 11cm balsa wood square: 50pc for £6 (12p each)
      5. 12cm balsa wood square: 5pc for £4.00 (80p ea.)
      6. 20cm wood rods: 20pc for £5.50 (28p ea.)
      7. 28cm (11″) candy floss sticks: Lowest: 5.5p ea (£5.50pc for 100pc), Currently: 100pc for £8.90 (9p ea) next day. These are excellent! Easy to snap off cleanly, and lightly sand to remove sharpness/splinters, wide enough to use a 2.4mm drill bit to drill a hole for a 2mm axle shaft to rotate within, great for making frames for lightweight items using hot glue.
      8. Craft Stocks – Jumbo: 19mm wide x 150mm, £4 for 100pc (4p ea, 1wk), or £4.20 for 50pc (8.4pc ea). Narrow: 10mm x 114mm
      9. Bamboo Paint Stirring Sticks: 40cm long, 10mm wide (1/2 width of wide craft sticks), 3mm thick £10 for 100pc (10p ea)
    6. 2mm beads – 1200 for £1.30 (c. 9 beads fo 1p) great as axle spacers, and chassis frame rods to stay in place
    7. Pinion/Sprockets 4x 18-24T £8 next day

    H. Storage Solutions (Cases, Containers)

    Low-cost, compact, secure storage solutions are essential for the amateur enthusiast. There are 4 main types: small components, medium project boxes, rugged cases, and hardshell/pelican boxes.

    1. Small components: For £6, get 5 boxes: 2x 10-compartment, 2x 15-compartment, 1x 24-compartment, providing a total of 74 compartments.
      1. 24 compartments (deep, good for holding ICs): Lowest price: £2.50. Currently: £3.00
      2. 15 compartments (thin, good for holding shallow electrical components): Lowest price: 99p ea. Currently: 4pc for £9 (£2.25 ea) next day or 4 for £10 (£2.50 ea.) multi-colored same day
      3. 10 compartments (compact, good for same part with less than 10 variations, e.g. switches): Lowest price: 69p ea (MOQ2). Currently: £1.00 ea.
    2. Project Boxes:
      1. The best medium project boxes I’ve found are the deep height plastic Chinese take-away boxes with lids. These just about fit a BB830 breadboard (800 tie-points) at the mouth of th ebox, so flipping the board upside down both protects the components and puts the widest part of your design against the widest part of the box. Cost: 30 min in the dishwasher after your next takeaway.
      2. 4 x 1.5L Whambox boxes with lids, Lowest price: £1.25 ea (MOQ5). Currently: £7.00 for 4 (£1.75 ea.) from Amazon.
    3. Rugged stackable cases. Recommend to get one of the following to hold the larger, odd-shaped items
      1. Stanley, £6
      2. Empty Raaco £8 + additional for inserts This is a spacious storage case as it is able to accept double stacked half-height inserts and singly stacked double-height insert. The issue is that the inserts are only available from Raaco, and have a £12 S&H fee
      3. Raaco inserts for blank Raaco storage boxes or workbench organization:
        1. RECOMMENDED: Raaco Insert A7-8 42p ea. x2, 8 compartments each Great for screws, tactile switches, header pins, and other small parts
        2. RECOMMENDED: Raaco Insert A7-5 42p ea. x4Half-height with 5 compartments
        3. RECOMMENDED: Raaco Insert A7-3 42p ea. x4. Half-height with 3 compartments, great for pre-cut hookup wire ready for use as jumper wires, of different colors.
        4. Raaco Insert 80 BA8-2 £1.30 ea. x2 Good for sheets of 20-25 resistors; one for >5KR one for <5KR
        5. Raaco Insert 55 A8-1 38p ea. x4Good for medium sized parts such as brackets, LED bags, fuses, switches, large capacitors, etc.
        6. Raaco Insert 55 A9-2 48p ea.Not used: For resistors, one folded sheet, need a minimum 70x35mm insert
    4. Pelican/hardshell cases:
      Pelican cases are able to withstand punishment (being stood on, dropped from height, etc.) Aluminium case not so much, and would not expect to survive flight in baggage hold.

      1. Pelican 1150 (24x19x12cm), £40, 1300 (26x24x17cm outside dims, 23.5x18x12cm inside dims), £70, 1120 (21x17x9cm), £35 Amazon Basics Medium (44x34x16cm)
      2. Max 23x18x10cm for £30
      3. Aluminium Flight Case 46x33x15cm for £29 or Perel 1829 (43x30x12cm) for £25, or (33x23x10cm) inside dimensions for £29

    References

    1. Electrical Symbols Reference and Periodic Table of Electrical Symbols
    2. Partfinder (Lady Ada’s reference) – This is a neat, comprehensive list with a similar intent to the above, organized in tables with pictures (note links are US-based).
    3. Spiratronics – Electronics Hobbyist Supply – UK (a.e; B*a) – Shipping £1.50 per order
    4. BitBox UK – excellent organized component catalogue
    5. Hobby Electronics
    6. Langrex Vintage Electronics, stocklist of Transistors, ICs, and Diodes (40,000 lines)
    7. Bits Box – Electronics Hobby Supply – UK
    8. Quasar Electronics – UK
    9. Rapid Online Electronics – UK
    10. Where to buy Electronics Hobby Supplies – by main countries
    11. AliExpress – Source direct from China(ae*0;r0*0)
    12. Sparkfun account (USA); (ae*0; r0*0)
    13. Flux Workshop
    14. Pololu Robotics & Electronics
    15. Switch Terminology
    16. Metric Prefixes Reference
    17. DigiKey – UK
    18. AWG to mm conversion
    19. Wire Gauge Size Chart
    20. Worldwide Voltage, Plug, and Socket Reference
    21. Understanding & Working with Capacitors
    22. Perforated Board
    23. Elegoo Device Datasheets and Instruction Notes – Downloads page
    24. Physics of Sound/Music; Frequencies of Musical Notes; C0 (16Hz) to B8 (7.9kHz)
    25. Online Tone Generator, for tuning various instruments
    26. Online Tone Generator, any musical note

    Inspiration

    Browse the cool projects of these intrepid builders:

    1. Hackaday – a site for experimentalist folks who like to play with microcontrollers and build cool things!
    2. Frank Sargent’s 3-instruction Forth (1991) for microcontrollers having serial UART capability at bootup. Frank wrote this for the Motorola 6811 which has a von Neumann architecture. I’ve written a version for the ATmega328P (the uC Arduino Uno/Nano) that works in a Harvard architecture chip by using a precompiled table of function pointers stored in SRAM (data memory) making the chip’s capabilities available over the serial line. You can request the code in the comments!
    3. Viktor Toth – 4-bit computer and the W programming language (his physics page, his Maxima page, his audio page)
    4. Dejan Nedelkovski – Mechatronics with Arduino Nano
    5. Petteri Aimonen – Essential Scrap, including steering mechanism, and some nifty inventions
    6. TurtleBot
    7. Karan Shaw – Trybotics – astounding array of Arduino projects
    8. Willow Garage – ROS – the Linux of Robotics
    9. Leon Maurer – AmForth for Arduino
    10. DF Robot.com –
    11. FX-Creations – Making it real
    12. Petapixel – Light and BitDepth
    13. Leah Buechley – Electronics in Art, Design, and Fashion, designer of the Lilypad product set.
    14. Pololu Robotics & Electronics
    15. Articulated Finger Extensions by Adrien R.
    16. Andrew Huang – Modular Synthesis demonstrated, Endorphines Shuttle System – Incredible Synthesizer demo! Andrew Huang, $2500 – modular synthesis
    17. Thomas Henry – Birth of a Synth designs – check out his SN-Voice samples using SN76477 complex sound generator IC as the core
    18. What’s Next? A hardware accelerator / incubator.
    19. Fantastic remote controlled car using Arduino Nano, SAMD21, and 3-D resin printed chassis
    20. Aiden Lawrence – a fully functional MIDI programmable sound generator system – developed from July 2017 – Mar 2019 – writeup
    21. Tindie Synths
    22. For $99, can get an SBC with an Intel Celeron, 4GB RAM, capable of running Windows 10 Pro
    23. Surface Mount memory chips
    24. Garage Projects from CMU students
    25. Easy Surface Mount Soldering using Schmart Boards
    26. Ben Eater’s 8-bit programmable breadboard computer from scratch using ICs. Complete kit of all parts $295, or 4 kits bought one at a time.
    27. Garage Build Week – Carnegie Mellon
    28. App controlled Flamethrower using ESP8266 (Sparkfun)
    29. Electronic music generators – arpeggiators
    30. Paul Bleisch, Remote controlled Arduino tank
    31. IC Station’s gadgets
    32. Paper Circuit cards made from copper tape (Sparkfun)
    33. e-Textiles (Sparkfun> and examples
    34. Hacking a Matchbox/Hotwheels car to make it an RC car!
    35. Awesome Fidget Spinner Rube Goldberg machine
    36. How to Get what you Want — ATTiny adventures
    37. Andrew Huang – Hologrm Electronics’ Microcosm Desktop Effects Pedal, for article see Engadget Review. Available direct from Hologram, $450.
    38. Kevin – 50 projects in musical electronics using Arduino Nano culminating in his lo-fi orchestra.
    39. Building a 3D Zoetrope: Mechanical Design, CAD, Motor control, Maths, Animation. – 3D Zoetrope Explained (video), Embroidered Zoetrope example (video)
    40. BroHogan (John) – Home Automation network with Arduino/X10. Also ESP8266 and control via Alexa. Solar charging, wireless, valve control garden watering system.
    41. David Touretzky (Carnegie Mellon University) 3D Printing – the next industrial revolution –
    42. Calypso intelligence framework for the Cozmo robot
    43. AI studies for K-12
    44. Drum Computing
    45. Norbert Heinz (Homofaciens) shows an impressive pick and place robot arm constructed from wood battens and long screw rods, run with an Arduino UNO with CNC extension board, controlled from a laptop running a Python positioning script. The explanatory video is efficient at explaining the design and is worth the watch! “This is fantastic. Great to see that cheap wood battens and long screw rods can provide a suitable frame for mechatronic experiments of the kind of precision shown in the video. Impressive indeed!”
    46. John P. Miller’s – Robotic Xylophone – Came across this nifty robotic xylophone built by John P. Miller (https://buildmusic.net/). Looks like a tidy 25-key affair, with nice solenoid action per key, allowing for simultaneous strikes of the bars. Especially noteworthy is the care John has taken in the build – a nice wood case, transparent plexiglass window exposing the inner workings (and that can be opened up for access or adjustment), and a “no solder” build approach. He’s clearly into transferring skills – evident in his rigging up a simple 8-key experimental version that children can play with at Maker Faires. I was most impressed with the PC software interface he built making it easy to curate and upload MIDI files to create playlists that his Robotic Xylophone can play. Well done to John!

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