Getting started with 8-bit Microcontrollers, Sensors, and Electronics Beware of programmers who carry screwdrivers, and are capable of interfacing with microcontrollers...

8051/8052 (8-bit). Investment: £86. Chip AT89S52. Software: Forth, Assembly, or C.

1) BOARD KIT: ATMEL 8051/8052 Development Board Self-Starter Kit by Technido (£74)
https://www.amazon.co.uk/gp/product/B01N1FK7YF

2) BOOK: 8051/8052 Microcontroller: Architecture, Assembly Language, and Hardware Interfacing (£12)
https://www.amazon.co.uk/gp/product/1627341773

AVR 8-bit. Investment: £18.

3) BOARD ONLY: Mega 2560 Development Board with ATmega2560 AVR chip (£13)
https://www.amazon.co.uk/gp/product/B06XKMZ3T9/

4) CASE: Case for ATmega2560.
https://www.amazon.co.uk/SB-Components-Enclosure-Transparent-Computer/dp/B00D6TW09Q/ (£5)

Sensor Kits. Investment: £41

5) Stepper Motors x 5 (£14)
https://www.amazon.co.uk/Elegoo-28BYJ-48-Stepper-ULN2003-Arduino/dp/B01LXT5740/

6) Kit of 37 sensors (£27)
https://www.amazon.co.uk/dp/B01M3TOXZN/

Electronics Fundamentals & Kit. Investment: £110

7) BOOK: Make: Electronics: Learning through Discover, Second Edition, by Charles Platt (£15)
https://www.amazon.co.uk/gp/product/1680450263/

8) Tools & Equipment: (£36)
see list here: http://mathscitech.org/articles/electronics

9) Supplies & Components: (£48)
see list here: http://mathscitech.org/articles/electronics

Inspiration

10) Ben Eater's How to build an 8-bit computer on a breadboard (2017)
https://eater.net/8bit/

11) Victor Toth's 4-bit processor (1999)
https://www.vttoth.com/CMS/projects/47-viktors-amazing-4-bit-processor