possible to project with an Capacitive Touch Sensor Breakout

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1

I am hoping to create an interactive tree stump, showing a record of time if you like. The idea is to project something different when each ring of the tree is touched. Would this be possible by marking the 12 individual rings with conductive paint and joining them to 12 different electrodes on a Capacitive Touch Sensor Breakout - MPR121 which will then be linked up to an arduino uno followed by my laptop/projector?

2

I don’t see why not. You may have to experiment with filtering in the code.

void mpr121_setup(void){

  set_register(0x5A, ELE_CFG, 0x00); 

  // Section A - Controls filtering when data is > baseline.
  set_register(0x5A, MHD_R, 0x01);
  set_register(0x5A, NHD_R, 0x01);
  set_register(0x5A, NCL_R, 0x00);
  set_register(0x5A, FDL_R, 0x00);

  // Section B - Controls filtering when data is < baseline.
  set_register(0x5A, MHD_F, 0x01);
  set_register(0x5A, NHD_F, 0x01);
  set_register(0x5A, NCL_F, 0xFF);
  set_register(0x5A, FDL_F, 0x02);

  // Section C - Sets touch and release thresholds for each electrode
  set_register(0x5A, ELE0_T, TOU_THRESH);
  set_register(0x5A, ELE0_R, REL_THRESH);

  set_register(0x5A, ELE1_T, TOU_THRESH);
  set_register(0x5A, ELE1_R, REL_THRESH);

  set_register(0x5A, ELE2_T, TOU_THRESH);
  set_register(0x5A, ELE2_R, REL_THRESH);

  set_register(0x5A, ELE3_T, TOU_THRESH);
  set_register(0x5A, ELE3_R, REL_THRESH);

  set_register(0x5A, ELE4_T, TOU_THRESH);
  set_register(0x5A, ELE4_R, REL_THRESH);

  set_register(0x5A, ELE5_T, TOU_THRESH);
  set_register(0x5A, ELE5_R, REL_THRESH);

  set_register(0x5A, ELE6_T, TOU_THRESH);
  set_register(0x5A, ELE6_R, REL_THRESH);

  set_register(0x5A, ELE7_T, TOU_THRESH);
  set_register(0x5A, ELE7_R, REL_THRESH);

  set_register(0x5A, ELE8_T, TOU_THRESH);
  set_register(0x5A, ELE8_R, REL_THRESH);

  set_register(0x5A, ELE9_T, TOU_THRESH);
  set_register(0x5A, ELE9_R, REL_THRESH);

  set_register(0x5A, ELE10_T, TOU_THRESH);
  set_register(0x5A, ELE10_R, REL_THRESH);

  set_register(0x5A, ELE11_T, TOU_THRESH);
  set_register(0x5A, ELE11_R, REL_THRESH);

  // Section D
  // Set the Filter Configuration
  // Set ESI2
  set_register(0x5A, FIL_CFG, 0x04);

  // Section E
  // Electrode Configuration
  // Set ELE_CFG to 0x00 to return to standby mode
  set_register(0x5A, ELE_CFG, 0x0C);  // Enables all 12 Electrodes


  // Section F
  // Enable Auto Config and auto Reconfig
  /*set_register(0x5A, ATO_CFG0, 0x0B);
  set_register(0x5A, ATO_CFGU, 0xC9);  // USL = (Vdd-0.7)/vdd*256 = 0xC9 @3.3V   set_register(0x5A, ATO_CFGL, 0x82);  // LSL = 0.65*USL = 0x82 @3.3V
  set_register(0x5A, ATO_CFGT, 0xB5);*/  // Target = 0.9*USL = 0xB5 @3.3V

  set_register(0x5A, ELE_CFG, 0x0C);

}