Finding alternative ways to unlock doors is a favorite hacker pastime. TkkrLab recently took on the challenge themselves. The hackerspace, which is located in the Netherlands, faced a problem common to communal workshops; how could they manage keyed access for a large number of members? The metal keys for the door are special, and cannot be cheaply duplicated. To further compound the issue, they are not the only tenants in the building so they can’t replace the lock with one that uses less-expensive keys. So they decided to add an electronic solution.
They first looked at a method for electronically opening the door. Often, this comes in the form of an electronic strike, but rather than alter the door jamb, they replaces the latching mechanism. The electronic latch was compatible with the original cylinder, which means the old keys still work in it. You can see the new assembly above. Just to the left of the lock is an iButton reader. We’ve seen this hardware in projects many times before. It’s cheap, and easy to work with. Now TkkrLab issues an iButton to each member, and can keep track of who is coming in door.