At points I might do something that might be dangerous because I'm comfortable with some tools or techniques but please ...

Basic circuit diagram of one of its channels is shown below ... Also note at this point that, if you want perfect galvanic-isolation, do not link Arduino’s ground rail (Gnd) to the relay module’s ...

This article describes the construction of a simple Arduino RFID ... as shown in the diagram above. Here, pin D12 of Arduino is used to drive a standard 5mm LED, and D13 is used to drive an ...