Electronics enthusiasts looking for a new project to keep them busy this weekend may be interested in this awesome fingerprint garage door lock which is powered by Arduino and has been created by Instructables user Joebarteam.
The project is not for the fainthearted but you can see the results in the demonstration video below which explains a little more about its construction.
Joebarteam explains more about the project and has kindly provided full instructions via the Instructables website which is accessible by following the link below.
This system consists of 2 main parts: An electronic part that is composed of power electronics, control electronics and programmable electronic: an Arduino The program is not necessarily the most optimized, free to modify it. If you want details on how the system works, you will find them in the program comments.
The second part of the system is exclusively mechanical. I have a swinging garage door like this one. So I was inspired by the existing locking system that I decided to “modify”. In the base system, there are two axes hanging on the door that slide behind the door frame, left and right to prevent it from tipping. So I imagined an electrically controllable system, with stepper motors, that can take in or out steel stem in soil.
I will detail the electronic part of the system and explain briefly the reasoning I had to create the circuit …
This system was designed for a garage door. The bistable relay serves to disable the communication between the sensor and the Arduino in case there are more than 3 false scanner fingerprints, or if the box containing the sensor Box that contains the electronic system) had to be opened or torn off. (Well yes, if the evil thieves open the sensor box and reprogram to accept their fingerprints, it’s not very secure!)
This is where the interest of using a bistable relay comes into play. A bistable relay, unlike a conventional relay, retains that switching position even if it is no longer powered. If the current is turned off, then nothing works, but if the current returns, then the Arduino “Reset” and if there was not a bistable relay then the communication between the sensor and the Arduino would be restored, and there, the Nasty thieves can go home if they reprogrammed the sensor and closed the box!