Tuesday, May 13, 2014

Multi-layer thickness | distance gauge (accelerometer) concept

I was always looking for a thickness or distance gauge that can measure thickness (in millimeters) of multi-layered (different materials) objects having relatively large span that can't be measured using rulers, vernier calipers, micrometers, or other traditional tools used for measuring thickness or distance.

To give a clear example of what I needed precisely, I was interested in measuring local thickness of fridge insulation at some points. Refrigerators don't have uniform insulation thickness in all points. A traditional ultrasonic gauge can't be used because there are at least three materials that it have to consider in measuring thickness: plastic liner, foam, and steel sheet. 

Therefore, I thought about a thickness gauge using accelerometer concept which was initially adopted by Russian navy as Inertial Navigation System INS to track ship location on offline maps (before using GPS). Modern smart phones have accelerometers in three directions that are used in speedometer applications.

My idea of multi-layer thickness gauge is to use the previously mentioned concept, but this require very accurate high-speed accelerometers and a well formulated double integrator. The idea simply is a pen, that will be referenced at the start point by pressing start button, then it will be moved to the end point and the displacement in three directions will be calculated. The following image shows the simple concept of the pen multi-layer thickness gauge. The pen gauge should be capable of calculating displacements for any random shaped paths.

I hope if this application will come true to the real world.