You cannot use the 5V from the USB to power up the transistor and the LOAD because the USB port usually delivers only ... Arduino board and the transistor + relay. The load uses its own power supply, ...

We’ve all been there: after assessing a problem and thinking about a solution, we immediately rush to pursue the first that comes to mind, only to ... Prefer your Arduino connections wireless?

So, let’s start by watching this 7 minutes video to see the entire system in action: The resetAlarm integer is the Arduino pin where we connect the button that is used the reset the alarm. The relay ...