Electrical – accelerometer interference


I had a PCB containing a micro usb and a 3 axes accelerometer LIS3DH. I put the PCB at fixed position and the value of Z vary between –77at -83. but when I touch the usb cable with my hand or with a material stuff and without changing the PCB position, I receive big glitches of the values of z (up to 700 on Z value).
is that really my hand which cause this fluctuation (knowing that if I dont touch the usb, the value would stay stable (-77 -83for hours)

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Best Answer

The accelerometer has a digital interface. It's fairly unlikely that you are looking at electrical noise or interference, and you're looking at accelerations that the device is experiencing. You should make an effort to put some numbers in real units on your Y-axis to figure out how large the accelerations are.