In this quick Arduino tutorial I will explain how you can control a relay using the Arduino Board, one 1K and one 10K resistors, 1 BC547 transistor, one 6V or 12V relay, one 1N4007 diode and a 12V fan ...

All it does is time the activation of the relays that control the gas flow, power, and wire feeder, so [Brett] decided to use an Arduino instead. The welders control circuit runs at 24V, so an ...