That is why you must use an external power supply (Vcc) that is between 7 to 12 volts to power up the Arduino board and the transistor + relay. The load uses its own power supply, for instance if you ...

The wiring is very simple so that even a novice can ... if necessary. // PANIC ALARM - ARDUINO // // by T.K.Hareendran // int rlyPin = 12; // Relay Output Pin int sensPin = 2; // Switch Input Pin int ...

It’s a fairly simple project, too: just hook an Arduino Uno up to a motion sensor and an electronic switch called a relay, then plug in your fan, and you’re good to go. If that sounds ...

but we can see the wiring getting out of control for someone like him with a reasonable number of relay boards to control. We’ve featured PCB manufacture in all its facets here at Hackaday over ...