Sensor for finger drumming (piezo, etc.)

[ZNX]

Hey everyone!

I'm working on a project where I need a sensor. The idea is to have some sort of sensor that can detect impact when you, for example, tap your finger on a surface. I've been looking into small piezos and film piezos but am not sure which direction to go. Small piezo sensors would work best for the bottom of a finger, but not so much the side. Film piezos are nice in that they could wrap around the bottom and side of a finger, but there might be some bend detection that may or may not interfere with the signal. It would be nice to have something that deals well with velocity but having just the impact for now would serve my intentions. Any alternative suggestions? (Thanks in advance.)

 

[Harald Kapp]

Looking for something along these lines?

 

[Bluejets]

Once made a knock sensor for my Dad (motor mechanic)
Previously he used an extra long screwdriver with the handle shoved in one ear and the screwdriver blade on any suspected source.
I used a " magnetic earpiece" as used in some crystal sets, with an aluminium rod afixed to the now removed earpiece into an amp and headphones.
Worked well.
He used my new device until the battery went flat and then reverted to his trusty old long shank screwdriver.

Note that there are similar looking earpiece which are crystal and do not work.