Description: The attached file illustrates a sensor matrix built by Sensitronics. I'm working on a pressure mat and my approach is pretty much the same. Current is injected through the bottem layer strips one by one and then you read the voltage across R1 parting from the upper layer "reading rows" one by one. I don't know if you get the picture, I'd be happy to provide more details if necessary.

Question: My problem is that the voltage measured for a certain cell (located at the intersection of row i with column j ) depends not on Rij but also on the resistance across all the cells from the same column. This induces errors (up to 80 %). I'm still trying to figure out a way to do it ? if there is any.

ps:
I'm using registers to illiminate ghosting.

 

hi U,
Look at this link.
http://blog.komar.be/how-to-make-a-keyboard-the-matrix/

Also Google keyboard steering diodes
E

 

Yes, it's possible to do this, but it takes a certain amount of hardware. Do you need this enough to build a circuit to make it more accurate?

That stuff about keyboards and a diode at each crosspoint is a complete waste of time.