Arduino user SamJBoz needed a way to quickly gain access to his garage when he did not have the remote. He designed a simple entry system with 4 digit access codes to allow himself, family and friends to gain quick access to the garage when a remote is not at hand, running on a 5V Arduino Pro Mini. The keypad allows for up to 10 4-digit pin numbers, has a user set master pin number to create and delete user pin numbers and flashes 2 color error codes if something goes wrong.
The hardware BoM consists of a 4×4 keypad, an Arduino Pro Mini, a small custom PCB and a few external electronic parts to complete the design.
He’s been using it flawlessly for a year and you could try to build one too: all the documentation is on github comprehensive of Eagle PCB files for the main board, the Arduino code, BoM, a user manual and some useful construction tips.