door-lock-keypad-controller's Introduction

Replacement Door Lock Combo Keypad Controller

The controller on the Kwikset combo door lock to my house died so instead of buying a new one I did the sensible thing and spent hours designing my own ;)

Features (watch video)

Low power consumption using MSP430 allow it to run on batteries for months/years
Easy programming with button
Combo stored in non-volatile memory so no need to re-program when swapping batteries
Pizo speaker for audible button presses
Components are inexpensive and easy to get
PCB is a small simple 2 layer board I was able to assemble with a hot plate and some solder paste (I have a few spares if interested)
Mosfet H-bridge to spin lock motor forwards and backwards

Img.6524-1.mp4

Notes:

My lock multiplexes the buttons into 5 connections/wires, they are as follows (You could probably modify the code if your lock is slightly different)
Row combos: 1/2 and lock | 3/4 and 5/6 | 7/8 and 9/0
Column combos: 1/2 and 3/4 and 7/8 | 5/6 and 9/0 and lock
I used Energia to program the MSP430, you'll want to put the MSP430 in DIP socket so you can remove it to program it. The PCB does not break out the programing pins
You're going to want to make sure the voltage regulator(3.3v) has a low quiescent current if you expect the batteries to last
The combo length is set to 4 in the code but this can be changed to a value up to 16
PCB designed with EAGLE

Below are pictures of my door lock and original PCB so you can see if maybe this design would work for you. It could also be used for a custom lock project.