One of the first things that [Eric] hacked together when he got to college was an RFID door locking system. He found that he was often in a rush to get in and out of his dorm room, and that using a simple wireless key was a great way to streamline his days.

Over the years, he has refined his design, and while his original prototype was functional, it was a bit rough around the edges. In the video posted on his site, he thoroughly explains how his system was built, and shows off the revisions he has made over time. One key consideration when building this system was the fact that the installation had to be non-permanent. Since schools typically frown on physically altering your rooms, he found a non-intrusive means to mount his system in the way of zip ties and foam board.

His RFID door lock looks to work quite nicely, and we especially like the inclusion of the reed switch to ensure that the system knows if the door has been opened or not. If you have about half an hour to spare and are interested in building an RFID entry system of your own, be sure to check out [Eric’s] video below for all the details.

[Pcmofo] has shared a well-built, well-explained example of how to implement an RFID key system for a door. We call this the right way because it is well thought out and functional. In the past we’ve seen doors that unlock via a secret knock, keypads, and RFID, but they are all non-permanent solutions capable being transplanted from one door to another. Rather than building a mechanism to turn the door handle, this implementation uses an electric strike mounted in the framing of the door to allow access. These are used for security doors in buildings and are built to keep your door secure.

The hack in this case is the electronics. Using an AVR ATmega168 running the Arduino boot-loader, [pcmofo] has prototyped a two-part design. An RFID reader is mounted outside the door with data wires running to the inside where the microcontroller resides. A hard-coded RFID card is used as a “master” to train any number of tags for entry. The master puts the device in training mode and the next tag to be read is added to the list of tags authorized to open the door.

We like messy wires and quickly thrown together devices but this is built to last and will look great once mounted in an appropriate enclosure.

[Michael] has a keypad in his previous car’s door and he missed it enough to hack one into his Dodge Caliber. He bought a Ford keypad and mounted it inside his door with some custom electronics. He started with an Arduino nano to receive and authenticate button presses. This then splices into wires in the door that control the door lock. The program has a 5-digit code to unlock the door, but simply pressing 1 twice will lock the doors. He also implemented a lockout feature to prevent people from brute-forcing the combination. Although it isn’t wireless, it’s significantly simpler.

[thanks Michael]