Hey look, it’s a new guide! The Coffee Detonator learning guide shows you how to use a TNT blasting machine to control your coffee grinder. That may seem a tad specific, but in reality this is a general guide to converting a high-voltage AC source to low voltage DC in order to read it with an Arduino-compatible microcontroller. What you do with it from there is up to you!

Use a high-voltage AC power source to trigger a Feather microcontroller-driven coffee grinder. This guide will show you how a magneto, generator, or other AC power source can be safely converted into a small DC signal easily read by an Arduino-compatible microcontroller. Then, the microcontroller can trigger a 120V relay to turn on any appliance!

The blaster starts out producing around 30V AC.

A full-wave bridge rectifier (four cleverly arranged diodes and a capacitor) and a voltage divider (a pair of resistors) bring this down to a lovely, microcontroller friendly ~3VDC to read on an analog pin.

It all fits neatly on a FeatherWing Proto board.

Coffee beans awaiting detonation.

Beautiful, beautiful ground coffee. Mmmm, that smells good.