newbie: piezo vibration sensor

I’ve seen a couple of really cool projects that use simple piezos as vibration sensors, i.e. for MIDI drums. In each of these projects, the piezo is attached to some larger, flat surface. The surface is struck and the piezo picks up the vibration.

I’d like to create something similar, but I’d like to be able to put the sensor into a stuffed animal. I’d like to be able to sense when the animal is struck. This means the piezo would not be attached to a hard, flat surface. Is there any way that the piezo would still be able to sense the vibration in this kind of setup, or would I have to find a more exotic (and expensive) sensor?

Thanks!

It would probably work, but you would have to touch or hit the piezo directly.

One problem is that the Piezo is quite fraigle, and without the stiff backing it can easily break.

I’d like to be able to put the sensor into a stuffed animal. I’d like to be able to sense when the animal is struck.

The cruelty of it all! (Although it did remind me of the Muppaphone. :slight_smile: )

–Phil.

The cruelty of it all! (Although it did remind me of the Muppaphone. :slight_smile: )

LOL, that’s awesome. For the record, I’m not creating a plush punching bag – though recreating those muppets as robots would be cool.

OK, so if a piezo may be too fragile, and requires direct contact, what are my other options? I have seen sensors like the LilyPad accelerometer, which would probably work, but is pricey and overkill for my simple application. I’ve also seen flex sensors, but I’m not sure if they could detect vibration as opposed to flexion.

What do you guys think?

hi

Maybe you could try QTC, it is available in various forms that might suit.
QTC is a material that changes resistance proportionally to the pressure applied & can act as a switch or potentiometer.
It is also inexpensive.

http://www.mutr.co.uk/catalog/product_info.php?products_id=1144

Lee

Could you use a simple spring switch? I’ve seen them in a bunch of devices I’ve torn apart. Basically it’s a bare solid wire or long machine screw, inside a spring that’s attached at one end. When the two touch, circuit is connected. Vary or bend the spring or attach weights at the top to control sensitivity.

See also:

Thanks for the info. :slight_smile:

That QTC material looks very interesting. I think I will give it a shot. Have you been able to use it in any Arduino projects?