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Mpr121 proximity settings and readings and the "13th" electrode

Question asked by Steven Herrnstadt on Mar 8, 2011
Latest reply on Oct 18, 2012 by johncohn

I am using Sparkfun's MPR121 breakout board. How can I read the rising and falling values from the proximity sensor(s) as they change in response to the varying distance between a hand and the electrode? Sorry to be such a noob. Sample code can be found at http://www.sparkfun.com/products/9695 I have read through the data sheets here at Freescale. I would like to set up the mpr121 through an arduino UNO and the arduino IDE or the Processing IDE to read proximity via the electrode levels. The distance the hand is from the plate will determine the piece's reaction based on the values read from that electrode. For instance, as a test, the closer the hand is to the plate electrode the brighter an LED will light. I have done some experiments with existing code but all I can get a solid off or on of the LED. When I read from register 0x2a I get only values of about 760 or 761 depending on whether I am touching the electrode or not. Using the code referenced above I can light up individual LEDs attached to each of the electrodes from ele6~11 when a piece of foil is touched. I have tried writing to individual registers setting ele0 ~ 5 to proximity and begun to change touch and release levels but nothing seems to react differently The code I am using the code listed by John Lindblom that can be downloaded from the Sparkfun product page(link above). This level of pushing bytes to registers is entirely new to me as are these levels of data sheet. I am taking code apart and experimenting but am at a loss right now. Thanks for any help.

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