Of course, you can also skip the PWM code and just use the timer interrupts for timing. It isn’t that the timer code or PWM isn’t workable without a tool.

Droplet and StackAR, developed by MIT’s Media Lab, allow users to set timers or program an Arduino using light-based communication. By pressing the tool against a screen, flashes of light can ...

You can use a microcontroller to build a clock. After all, a clock is just something that counts the passage of time. The ...