Arduino Keypad Door Automation. November 1, ... Down the road he’s also planning on adding a knock sensor using the small speaker that is already part of the circuit, because, why not?

Keypad pin 4 to Arduino digital 8 //R4; Keypad pin 5 to Arduino digital 4 //C3; Keypad pin 6 to Arduino digital 7 //R3; Keypad pin 7 to Arduino digital 6 //R2; Since keypads are available from many ...