Thread: Automatic Lock/Unlock Using DC Motor

I am currently working on a project to install a keypad on my door that will lock and unlock my door if the correct combination is typed into it. I have everything working except I am having problems getting the circuit to reverse the motor, which would unlock the door. I have been looking into using an H-Bridge but would like something more compact that will fit into the relatively small area of my door lock. Any ideas on how I could get the motor to unlock my door?

~HP

Could you use a solenoid (an electromagnet) or pair of them to kick a bolt one way or the other?

EDIT: Simplest I think would be one solenoid that just pulls the bolt so long as you push a button. Let go and the bolt springs locked. It'll make a satisfying "thunk" sound too.

There are actually electronic door locks based on solenoids for sale. They cost about 25 dollars and you don't have to fool around with any motors that could potentially fail.

The solenoid door locks go inside the wall part of the door, so when the door closes, the latch piece sticks in, just like a normal door. This way, you can also just use a key, normally. They are composed of a spring loaded latch, a solenoid, and a metal plate that stops the spring from opening when you haven't activated the solenoid.

Alternatively, if you want to continue along the path you're using, you could get a servo motor that operates both directions.

An H-bridge wouldn't take up much space, especially if you used the IC kind.