We’ve covered interesting methods for opening doors before, however, this DIY project will allow you to open your door from anywhere, just by using your cell phone.
The basic idea behind this project is that you create a device that can decode certain beeps emitted by a phone and release the lock when the correct sequence is entered. Since each number on a phone generates a unique sound, it is perfect to use.
The project will take a little time and effort to complete, but in the end, you’ll have the coolest lock in town. Though you’ll need a working cell phone able to receive calls in order to make this work. You could always use a prepaid phone, but I’d be worried that I would run out of minutes at a very inopportune time.
Cell phone controlled door lock [via hackaday]