ESP32 stopwatch with lap times on an 8-digit MAX7219 display
Open in the lab ▸Make my own copy
Start/Stop and Lap/Reset buttons, hundredths of a second on an 8-digit 7-segment display. The MAX7219 drives all the digits by itself; the ESP32 only sends it two-byte commands over SPI. Buttons are read on their falling edge, so holding one counts once. Open it and press Run: the sketch is inside the board (click the board, then Code). Every part, pin and resistor matches what you would build on a real breadboard; the guided build of the same name has the test sheet and hidden faults.
What is on the bench
7 parts, 14 wires, with a sketch (the program runs in the lab). Boards: ESP32 DevKit.
| Push button | 2 |
|---|---|
| Bench power supply | 1 |
| ESP32 DevKit | 1 |
| USB charger / port | 1 |
| MAX7219 8-digit display | 1 |
Put it on your page
The project runs live inside the frame: readers can press buttons, turn knobs and read the meters.
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Link
https://zencircuitlab.com/p/zclcwatch
Published by its author under the lab's community terms: it may be opened, copied and changed by anyone. Simulation results are for learning; check a real build against the parts' datasheets.