Summary of chipKIT Project 5: Digital stopwatch on seven segment LED display
This project creates a digital stopwatch using the chipKIT Uno32 board, capable of timing minutes, seconds, and tenths of seconds with start and stop functionality. Time is displayed on an 8-digit seven-segment LED module driven by a MAX7219 chip. The stopwatch resets using the Uno32 board’s Reset switch and toggles start/stop via a button connected to an interrupt pin, with an RC debounce circuit ensuring stable switching. It measures up to 99 minutes before rolling over to zero.
Parts used in the Digital Stopwatch Project:
- chipKIT Uno32 board
- MAX7219-driven 8-digit seven segment LED display (SPI7SEGDISP8.56-1R module)
- Tactile switch (Start/Stop control)
- RC debounce circuit components (Resistor R2 and Capacitor C1)
- Breadboard for switch and debounce circuit assembly
- Connecting wires
Theory
A stopwatch is a timepiece that measures the amount of time elapsed between the time when it is started and the time it is stopped. Stopwatch is useful in many activities, including sports, games, and cooking, for timing events. We are going to construct a digital stopwatch using the chipKIT Uno32 board and the SPI7SEGDISP8.56-1R display module. The stopwatch will have the time resolution of 1/10th of a second or 100 milliseconds, and maximum measurable interval of 99 minutes, after which the stopwatch rolls over to zero again. More details on the MAX7219-based serial seven segment display interface can be found here.