AND gate implemented as diode-resistor logic. (Credit: Anthony Francis-Jones) The fun part about logic gates is that there are so many ways to make them, with each approach having its own ...

Arduino Uno R3 DFPlayer Mini 3 relays I also connected the Ignition Wire to this system — meaning when I turn the key ON or OFF, the Timer Relay gets a pulse too. So no matter if I lock, unlock, or ...

The wiring is easy to remember – wire the diodes in a way that they don’t conduct from 3.3 V to GND, so, in reverse, same way you’d wire up a diode to shunt a relay coil.