Inductive scanner maps objects

-March 18, 2014

Presenting the 2nd prize winner in the TI LDC1000 inductive sensor design contest.

My original idea was to use the LDC1000 to sense the liquid level in a low cost resin style 3D printer, but after receiving the dev kit and seeing the performance of the part, I decided that the LDC1000 was probably not the best solution for liquid level sensing in that design. In order to achieve the sensing distance that I desired (about 4 inches) the coil needed to be much larger in diameter than I was designing for. Also the non linear output of the LDC1000 with respect to distance meant that the device would need to be accurately calibrated by some means after it was installed. Instead I decided to build what I thought would be truly awesome, the Inductive Scanner.

The inductive scanner that I created uses an old pen plotter as an X-Y table. Glass from an old flat bed scanner acts as a platform to hold the object being scanned while also letting you see where the scanning inductor is for easy alignment. A stepper motor controller that I designed is driving the motors in the X-Y table. A Matlab script tells the X-Y table how to move while also recording readings from the LDC1000. During the scan there is a live display of the results from Matlab.

The grid that is etched on the glass platform makes it easy to line up an object to be scanned and size the scan appropriately. I have a webcam mounted above the scanner that takes a picture of the object being scanned. The heat map that is generated as a result of the scan can be superimposed on the webcam picture easily using the grid on the platform. For clarity in my video submission I did not superimpose the heat map but instead provided side by side images.

Thank you for creating this competition. I have enjoyed my time working with the LDC1000 and I've already thought of a couple more projects I am going to build with it.

Other Sensing Design Challenge 2013 winners:

Also see:


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