Fastest finger first indicators (FFFIs) bring precision to quiz games, measuring contestants’ reaction times with accuracy.

The 9x9x9 LED Cube is a versatile platform for 3D light-based visualization, interactive applications, and gaming experiments. Its modular design, BLE support, and custom rendering capabilities make ...

You could put the Arduino in deep sleep, if you wanted to and that LED will still blink. With a little work, you could probably adapt this idea to any number of circuits out of the 555 playbook ...