Piezoelectric Force Sensor Testing

[gregolive]

Hello,
I am working on a project where I am using piezoelectric force sensors and logging the data on a Teensy 3.6 micro-controller. I am currently testing the sensors at a drop tower and have a question about the results. When testing at lower loads (~700N) the force sensor performs as expected with a spike upwards at impact (see attached photo), however at higher loads (~1800N) the spike goes slightly up, but mostly down at impact. Has anyone experienced this before? Thanks for the help!

[rhb]

Post some photographs of the setup for both cases.  A wild guess is that the larger load is deflecting the sensor support.  But that's all it is, a wild guess.

[Ian.M]

Your Teensy data logger doesn't have a high enough sample rate to see what's actually happening.  Can you capture the spikes at a much faster timebase using a DSO so we can see more detail?

Also, in addition to the photos rhb requested, the schematic of the signal conditioning circuit and datasheet of the sensor would be helpful.