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Help with MPR 121 Touch Sensor

Question asked by johncohn on Sep 23, 2012
Latest reply on Dec 19, 2012 by Brad Stewart

Folks,

    Not sure I'm posting this in the right place, if not, please point me to the right place.

 

I'm using an MPR121 + arduino  in a musical device and its working quite well. I'm doing trial and error changes on the settings for touch and release thresholds, auto calibration modes and debounce settings. I have it working pretty well, but I'm now trying to do some final tuning in which I'm trying to balance touch sensitivity to noise sensitivity and latency. I've read the MPR121 tutorials.. but still am struggling a bit. While I'm successfully writing the config registers, I can also read the key press register (0x5A) One thing I have not figured out how to do is to read the other internal register values (eg. the raw sense value, the current baseline, etc )   on the device and print them  to the serial monitor in the Arduino. I've tried using the same scheme to do an I2C  read for other registers.. but they always come back 0's.  Does anyone have a code fragment that shows how to read these register values..  ?

    Also.. does anyone have any suggestions on a process to optimize the the touch/release thresholds for a specific configuration ? Ive tried to work things out from the mfg tutorial at http://cache.freescale.com/files/sensors/doc/app_note/AN3889.pdf   but its a little academic.. 

   Any help / guidance on this would be much appreciated. Thanks !

-jc

 


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