You cannot use the 5V from the USB to power up the transistor and the LOAD because the USB port usually delivers only 100mA, and this is not enough to switch the relay and ... LOAD to the arduino and ...

Inside is a RTC (real time clock) with battery backup for timekeeping along with an Omron 5V relay to drive the garden ... for the full write-up, links to code and more details, then take a ...

This Arduino Uno setup can be powered by a 6F22 9V battery or other suitable power source, but it is up to you. The next piece of hardware is a dual-channel, low-trigger, 5V relay module. This relay ...

Her code allows you to configure the type and number of RFID cards required to trigger one of the Arduino’s digital pins, which usually would be connected to a relay to fire off whatever device ...