Detecting a knock on a door

[alistair.monaghan]

Hi there, is there a phidget sensor available that can detect a knock on a door? bearing in mind the door could be 3-4cm thick? Noise detection may not be a viable option as this is for a museum space.

Thanks in advance

[mparadis]

You can use a MOT1100 Accelerometer Phidget to measure vibrations. If you can mount it on the other side of the door close to where you expect the knocking to occur, it will easily be able to pick up the vibrations.

You'll probably have to do some calibration and/or logic to filter out false triggers from other vibration sources (e.g. someone jumping or stepping near the door). You could write your program to only trigger when multiple knocks of a specific magnitude happen in a certain time span.