Front door bolt unlocker

Opens your front door!
see video of the end result


Front door bolt unlocker
– 4xAA Rechargable Switchable Battery Pack + case
– Continuos Rotation Servo. (You can also a regular servo, with some modifications to the software) I used – Futaba S148
– Bread board
– RaspberryPi1 Raspberry Pi Model B + WiFi card
– Raspberry Pi Cobbler
– A piece of string (not sure how long you'll need, i used about 5 feet \ 1.5 m)
– Weight – I used a bottle of water, because I can easily adjust its weight
– Cable tie
– Over the door coat hanger
– Rubber bands
– Adafruit's PWM kernel module for the PI. Available in Occidentalis v0.2. The software I wrote uses this module.

Step 1: Assemble Electronics

Pretty basic. It's important to use rechargeable 1.25 V batteries. 4 Regular 1.5 V batteries are too much for the PI!!
Connect the servo to the PWM pin (#18) on the PI.

Step 2: Mount the parts on the door

Using an over the door coat hanger and rubber bands, mount all the parts above your front door.
Make sure that the servo is facing you.

Front door bolt unlocker Schemetic

Step 3: Tie loose ends

Tie the Sting:
– One end goes on the bolt of the door. Secure it using a cable tie.
– Stretch the string towards the servo, and make  a loop tie there, so the loop can hang loosely on the servo.
– Tie the other end of the String to your weight


For more detail: Front door bolt unlocker

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