Makers love making things - that's where the word comes from, of course - but most also love remaking things, reusing existing components or re-purposing something outside its original designer's intentions to create something new and exciting. Something like a door lock powered by an electric pepper mill, perhaps.
Mario Mueller's latest project is exactly that: an electronic door lock capable of recognising gestures, powered by an Arduino microcontroller. The pepper mill comes in because Mario didn't want to take the approach of many electronic door lock projects and replace the existing lock or add a second, but rather wanted to add new capabilities to the existing door lock. The pepper mill features a surprisingly powerful motor, used to grind the peppercorn into powder, which is perfect for rotating the existing lock system on demand.
The gesture sensor is configured to recognise a specific pattern, known only to those authorised to enter. While obviously less secure than a biometric system or good old-fashioned key - anyone standing nearby can observe the gesture required to unlock the door and duplicate it - it's a neat trick for lower-security areas, and one which serves as a great variant on the traditional pattern-recognising knock-sensor locks.
Although it would be possible to create a neater solution with a dedicated geared motor, Mario's implementation has the advantage of price: high-powered geared motors capable of turning the lock aren't cheap in single units, while the pepper mill added just a few pounds to the project's bill of materials (BOM).
Full details are available on Mario's Instructables page.
I was searching for an Instructable that is reusing the built in door lock to make an electric door lock without using the key manually. All I found were Instructables with a separate additional second door lock. So I started to build my own one to reuse the built in door lock.