[PD-ot] piezo-electric sensors

[marius schebella]

if I understand you correctly, you use the piezo sensors as microphones. 
I think you need to use an amplifier to get good data. otherwise, the 
signal will be too weak.
building your own amp on a breadboard is tricky, you need some extra 
electronic parts. (there should be a tutorial on physical computing sites).
if your problem is really only the capacitance, then pull the charge off 
by inserting a pull-down resistor or a voltage divider.
marius.


Patrice Colet wrote:
>   Hello, I'm trying to build a system for getting impulses from bouncing 
> balls on a medium board, for driving sounds or a step sequencer.
> 
>   The cheapest solution was about using a piezo-electric disc, that 
> transform the mecanic impulsion into electrical energy. So I use the 
> analog input of the Arduino interface for receiving this energy amount, 
> and then I just have to choose a threshold level of the released energy, 
> for triggering into PureData.
> 
>   But the problem I'm encountering is that the electrical circuit made 
> by the piezo probe and the arduino, with no other additionnal component 
> has a too high capacitance, so the energy level is lowering too slowly 
> after each mecanical impulsion, then my system doesn't trig anymore 
> until the circuit capacitance goes below the threshold level set in 
> PureData.
> 
>   There certainly is an electronical trick for discharging the energy 
> just after each impulse, maybe someone that read this message has 
> sufficient skills in electronics to help?
> 
>   Thanks,
> 
> pk.
> 
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