Project 8 (Moderate): Box Lock with Vibration Sensor (Cheap Version)

 After learning how to use a piezo element as a vibration sensor, I decided to give it some real life use. The piezo sensor will detect the number of knocks on the box. Once the correct pattern is detected, the box will be unlocked. I'll be using a servo motor and a plastic hook that I found as a lock.

Features:
- a piezo element will be used to detect the knocks
- Once the correct pattern is detected, the box will be unlocked.
- to re-lock the door, simply press the button. The lock will be engaged 10 seconds later













Parts:
- 1x piezo element
- 1x servo motor
- 1x push button
- 1x 10k ohm resistor
- 1x 1M ohm resistor
- an external power source (I used a 9 volt battery, salvaged the input jack and a 9v battery holder)

Piezo Vibration Sensor

Lock Socket

Lock Unlocked

Lock Engaged

This is a very basic and cheap way of unlocking a door lock through vibration. Instead of using duct tape, I could screw in my servo motor(and the plastic hook) directly onto the box, but I want to reuse my motor for future projects.When I gather the appropriate materials (different box, a reliable locking mechanism), I will make a better version of this project, and perhaps add more features.