Build kit

A Watch and a Game from Gates

A handheld LCD game with a watch — built by hand from logic gates in a browser simulator: from a single glowing digit to the game "Star Harvest" with score, speed, a comet and sound. No processor.

Start for freeBuy · 39 €

The introduction and lessons 0–1 are free; the rest opens after purchase.

What is inside

  1. Before you start
  2. A little history: handheld LCD games
  3. Lesson 0. Logic: 0 and 1, gates from transistors, an adder
  4. Lesson 1. BCD → 7-segment decoder
  5. Lesson 2. Memory and a 0…9 counter
  6. Lesson 3. Seconds 00…59: two digits and a carry
  7. Lesson 4. An HH:MM watch made of blocks
  8. Lesson 5. Setting the time
  9. Lesson 6. Real time, SET mode and "one press = +1"
  10. Chapter 1 summary
  11. Before chapter 2
  12. Lesson 7. The game screen and a 60Hz clock
  13. Lesson 8. The astronaut's pose: 4 buttons → a register → body and arm
  14. Lesson 9. Pipes: the crystals roll
  15. Lesson 10. Catching and missing
  16. Lesson 11. Waiting for START, the game, game over
  17. Lesson 12. Speed: the more points, the faster
  18. Lesson 13. The comet
  19. Lesson 14. Sound
  20. Chapter 2 summary
  21. All the parts
  22. Instructions in pictures
  23. Something doesn't work