# Measuring Displacements Using Accelerometers: Part 3- Testing And Video

EDITED 20/05/2017

In the last post I showed the results from a test of a few millimeters but that was one of the last tests I conducted, first I tested the output of the gyroscope compared to the angle moved which I talked about before, then tested measuring a linear movement, then a movement made up of both linear and angular movements and then finally I tested the device for its initial purpose. As I already discussed testing the output of the gyroscope, I’m going to talk about the linear movement tests. I tested the device ability to measure a linear movement by mounting the sensor on a rack of a rack and pinion controlled by a servo and by controlling the angle of the servo I could repeatedly move the sensor a known distance. I don’t have a picture of the actual setup but for a visual of it, I created it on CAD.

So the sensor in black was laid flat on the rack and moved varying distance and the output of the accelerometer was compared to the calculated movement. The movement was calculated by using the equation for the length of an arc that the gear moved, this would be translated to linear movement to the rack.
$L(\Theta)=2*\pi*r (\frac{\Theta }{360})$