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.
[Viktor], one of our favorite avid hackers, has been playing around with 1-wire systems all this month. What started out as a MicroLAN Fonera has turned into an iButton interface, to a 1-wire powered hub, and finally a 1-wire character driven LCD. Anyone looking at 1-wire systems or OWFS could surely benefit from his testing.
However, if you still haven’t gotten your fill of 1-wire goodness, let us remind you of the 1-wire HVAC and IPv6 to 1-wire protocol translator.
Maxim’s iButtons, which are small ICs in button-sized disks, are starting to show up in more and more places. They have a range of uses, from temperature loggers to identification, and all use the 1-wire protocol to communicate. Over a furrtek, they hacked an iButton used for buying things from vending machines and created an infinite money cheat. They built a small rig based on the ATmega8 to read and write data to the chip. The data was encrypted, so it wasn’t feasible to put an arbitrary amount on the card. Instead, they used a similar technique to the Boston subway hack and restored a previous state to the iButton after something was bought. They also created a hand-held device to backup and restore the contents of a button for portable hacking.