Secret Knock Detector
Difficulty
Summary
We saw this project on Instructables, and had to try it for ourselves. Of course, we ended up using all the Duinotech parts we had around. It uses a piezo transducer as a microphone to detect knocking, and then activates a relay if the correct knock sequence is detected. The original project was designed to unlock a door, but our version has a relay output which you could use for just about anything.
Materials Required
| 1 | Arduino Compatible Nano Board | XC4414 |
| 1 | Arduino Compatible Mini Breadboard with 170 Tie Points | PB8817 |
| 1 | 150mm Plug to Socket Jumper Leads - 40 Pieces | WC6028 |
| 1 | Arduino Compatible 5V Relay | XC4419 |
| 1 | 4.2kHz Audio Transducer | AB3440 |
| 1 | 2.2M Ohm 0.25 Watt Carbon Film Resistors - Pack of 8 | RR1656 |
| 1 | Arduino Compatible RGB LED Module | XC4428 |
Table of Contents
Future Improvements
The Instructables page has some good suggestions on how the software can be changed, including printing out the code and changing the default code.
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