Make or buy a RC circuit?

Grumpy_Mike:
What frequency do you want this smoothed signal to change at?

Have you read this:-
http://www.thebox.myzen.co.uk/Tutorial/PWM.html

I read your post, thx.

So, I need to move my piezo quickly, take a picture and then move again.
I'd like a framrate of 200Hz. That means that after I take a picture, with a short short shutter speed, the piezo has less than 0,005s to move to a new position and become stationary.
The voltages I'd like to apply are 0,1,2,0,1V ...
So from the Arduino I write the voltages with PWM, and the piezo is connected in parallell with the capacitor. From your post I'd say I need a cut-off frequency of roughly 1kHz.

When it comes to the filter order i think 1st or 2nd should be adequate.
Could you provide a link to a online store? I have actually tried to google a lot.

MarkT:
A piezo transducer is already a capacitor by its nature - you may only need a series resistor
to get low-pass filtering. Some experimentation needed of course.

I wasn't aware of this. So your saying i could hook up the piezo directly to the PWM-port and to GND (Possibly with a resistor in between). I'm reluctant to trying it, since I might destroy my piezo if it doesn't work. Do you have any theory supporting this?