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 ...

Instead of buying a new thermostat he and his friend [Doug] set out to build an Arduino ... switch 240v so they’ve used a transformer to power the logic circuitry and a solid state relay to ...

A few holes were drilled into the case to make room for the Ethernet connector as well as a USB connector. Two relays were used to allow the Arduino to switch the heating element and mixer motor ...