DrDiettrich:
Then I'd check the piezo signal again. You have shown one pulse, which may be followed by a second pulse. Can you give a circuit diagram of the piezo interface?
Thanks a lot for thinking along. What I did to get a proper signal into the Arduino is the following:
- Opamp 1: Amplifies the signal (piezo delivers small signal)
- Opamp 2: Comparator opamp
The result I see on my scoop is a nice "pulse" (40-50 ms wide). With no other pulses afterward. I can send some other images from my oscilloscoop.