Here's the finished code, ready to be customized and uploaded to your Circuit Playground Express.
This code works just like a chess clock: there is a 15 second timer that lights up in red attached to button A, in blue on button B, in yellow on touch pad A2 and green on touch pad A5.
Pressing any of those four inputs will start that player's timer. If the timer runs out, a "wawawawa" sound plays and the lights blink in that player's color. Pressing any of the inputs will reset the timer and start a new timer in the new player's color.
Click "Download" below to download the code as-is. Plug your Circuit Playground into your computer's USB port and upload by dragging the file you just downloaded onto the CPLAYBOOT drive that appears. (Don't see it? Try pressing the reset button in the middle of the board)
Customizing the Code
Or, click the edit button in the top right corner below to open the code in MakeCode so you can edit it and customize your colors and timer length.
Look in the