Garage is one place that need to be protected but also has to be convenient to access. When driving in and out a remote control is great choice. SamJBoz had a problem with his remote control so he decided to build in a keypad controlled system based on arduino.
Keypad system uses 4 digit pin codes for opening lock. Each family member has its own pin code. User with master code can enter and delete new users. Arduino Pro Mini sits on a custom PCB which has necessary connections for keypad, Piezo buzzer, LED and other. Eagle files are available for download.