Powering 12V keypad through Arduino Uno
How can I power the 12-24V keypad through the arduino without frying it?


If you power the Arduino with slightly more than 12V (through the barrel jack) then you can get 12V (or slightly less than you power the Arduino with) from the VIN pin.

However the Arduino's on-board voltage regulator does tend to get a little hot when such a high voltage is used to power it. Better is just to power the keypad separately from the correct power source.

And don't forget to connect the grounds together.