It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of ...

Microcontroller demo boards such as the Arduino UNO are ubiquitous on Hackaday ... a fully-functional Arduino happily running the blink program. He plans to encase the brass portion in resin ...