Remember the PIC 16F1937 Capacitance Touch Switch Keypad Project that we featured last week? Giorgos from PCB Heaven has been hard at work integrating the keypad into a larger project which is a DIY Keypad Door Entry System. A bunch of videos can be seen here and the build log with lots of pictures can be found here. If you want to build your own Giorgos has made the schematics and firmware available also.
“I hacked a normal keylock and added an RC servo to pull the “tongue” of the lock. A PIC16F1937 is used to control the servo. The keypad has a second PIC 16F1937 which acts as a 10-buttons capacitance touch sensor. The controller PIC stays into sleep all the time to save power. In sleep mode, the device draws 16 micro-amperes. When the operator pulls the door gently, a mechanical switch wakes up the controller PIC (with a pulse to RB0/INT port) which in turn provides power to the touchpad. To open the door, you pull the handle, enter the code, pull the handle again to activate the servo.
To change code, you pull the handle, enter the code, pull the handle again but you keep it pulled for 3 seconds until you hear the distinctive long beep. Then you enter the new code two times.”
