In the famous play Waiting for Godot, a pair of characters wait for someone named Godot who never arrives. While this might appear to be a rather uninteresting plot line, it was at one time voted the “most significant English language play of the 20th century,” so it seems you can’t always judge a play by its one-sentence summary. As seen here, the Godot Machine attempts to recreate this concept of waiting on an event that may happen soon, in a long time, or never in an electronic device.
The build takes the form of an Arduino Nano powered by a solar panel and a bank of capacitors. When the bank charges up to ~5V via a Joule thief energy harvester setup, the Nano turns on and generates a 20-bit number. This is displayed on a bank of LED lights, and compared to a number generated and stored in EEPROM the first time the circuit was turned on. If it matches this number, this fact is stored in EEPROM as well, and a green LED and piezo buzzer are activated. If it doesn’t match — the odds of matching are around 1 in a million — it eventually shuts down to try again.
It’s an interesting idea, and as it certainly hasn’t been entirely tested, one has to wonder if it will work as planned. You can check out the code for yourself on the project write-up to see if this event will indeed never happen. Notably, it uses a custom random number generator, which might be worth a look by itself if you’ve ever wondered how this works.