[DanielN]

I've been building a lockitron clone using a raspberry pi. The key functionality selling point for me was being able to lock/unlock the door base on proximity like lockitron's "sense" feature.

Turns out this is much more difficult than it sounds because bluetooth le rssi is pretty unreliable. I've figured how to get it working for my particular case but I would be curious how lockitron configures it to work consistently for a wider range of locations and devices.

On a separate note, the servo can be attached to the door without duct tape or modifying the door if you have a door like [1]. I simply bought a piece of rubber tubing that fits over the knob and then configured a smaller piece of rubber to fit the servo arm to the lock piece on the knob. This design is also nice in that if the device malfunctions a key can override it.

1 - http://www.happynews.com/living/livingimages/remove-door-kno...

[jonmarkgo]

That's a good solution, did you just mount the servo to the door itself?

[DanielN]

The servo is mounted to the piece of rubber which is then mounted to the doorknob. The only thing keeping the servo on the lock is friction.