Cigar Box Guitar piezo film pick-up.
Now, that looks different from a piezo disk doesnt it?
NOTE. This module has two modes. One is analogue so good for sound and the other is digital and ideal for a stomp box trigger.
My kit came with a pcb module but no instructions :\ but was only £4.51 + VAT & P&P (Farnell or CPC)
So here is what I found:
This is an Arduino compatible piezo film vibration sensor. It is made up of flexible piezo film and converter board. The sensor is able to detect vibration, flexibility, impact and touch.
The film is a flexible component comprising a 28 μm thick piezoelectric PVDF polymer film with screen-printed Ag-ink electrodes, laminated to a 0.125 mm polyester substrate, and fitted with two crimped contacts. As the piezo film is displaced from the mechanical neutral axis and bending creates very high strain within the piezo polymer, high voltages (from about ±28V to about +-90V depending upon size) are generated.
When the assembly is deflected by direct contact, the device acts as a flexible "switch", and the generated output is sufficient totrigger MOSFET or CMOS stages directly.
The module uses universal Gravity 3Pin interface that is easy to plug and play. It comes with Digital and Analog two output signals, which is suitable for all kinds of different applications. The piezo vibration sensor is not only able to detect strong shocks, but also to detect slight vibrations.
There is an on-board sensitivity adjustment potentiometer, you can adjust it to increase/decrease the output threshold value.
As provided,and despite the text on the website, the module has an input impedance far too low for a good wide audio range, so dont bother with this module as it is, but I think it can be easily modified to work, by changing two values. Meanwhere the piezo pre-amps shown elsewhere in this site can be used to better effect.
The actual piezo film sensor has a wide dynamic range (0.001Hz~1000MHz) also guarantees an excellent measuring performance.
General view including of my hand.