cap sensor 7/11

    //----------------------------------------------------------------------------------------
    //|     AD7747 Capacitive Sensor                                                         |
    //|   Based on code by  MiG found at:http://forum.arduino.cc/index.php/topic,11882.0.html|                                           |
    //|                                                                                      |
    //|  Author: Aidan Williamson (although I didn't do much original work)                  |
    //|  Written: 7/3/2014                                                                   |
    //|  ad7747 datasheet:http://www.analog.com/static/imported-files/data_sheets/AD7747.pdf |
    //|                                                                                      |
    //|                                                                                      |
    //|                                                                                      |
    //|                                                                                      |
    //-----------------------------------------------------------------------------------------
    #include <Wire.h>                  //include the library for i2c communication

     //int capreadybit = (bitRead(TWDR,0));  //initialize variable readybit to be two wire data register's lsb

    void setup()
    {
      Wire.begin();                   //sets up i2c for operation
      Serial.begin(9600);             // we will monitor this via serial cable
      Wire.beginTransmission(0x48);
      Wire.write(0xBF);
      Wire.write(0x00);
      Wire.endTransmission();
      delay(4);
      Wire.beginTransmission(0x48);   // begins write cycle
      Wire.write(0x07);              //address pointer for cap setup register
      Wire.write(0xA0);              //b'10100000' found from datasheet page 16
      Wire.endTransmission();        //ends write cycle
      delay(4);                      // Wait for data to clock out? I'm not 100% sure why this delay is here (or why it's 4ms)
      Wire.beginTransmission(0x48);   //begins transmission again
      Wire.write(0x09);              //address pointer for capacitive channel excitation register
      Wire.write(0x0E);              //recommended value from datasheet
      Wire.endTransmission();
      delay(4);
      Wire.beginTransmission(0x48);
      Wire.write(0x0A);              //address pointer for the configuration register
      Wire.write(0x21);              //b'00100001' for continuous conversion, arbitrary VTF setting, and mid-range capacitive conversion time
      Wire.endTransmission();
      Wire.beginTransmission(0x48);
      Wire.write(0x0B);              //CAP DAC A Register address (Positive pin data)
      Wire.write(0x80);               //b'10111111' for enable Cap DAC A
      Wire.endTransmission();
      Serial.println("Hello!");        //test to make sure serial connection is working
    }


    void loop()
 {
      Wire.beginTransmission(0x48);   //talking to chip
      Wire.write(byte(0x00));                  //status register address
      Wire.endTransmission();
      Wire.requestFrom(0x48,1);       //request status register data
      int readycap;
      readycap=Wire.read();
      if((readycap&0x1)==0){                // ready?
        Wire.beginTransmission(0x48); //arduino asks for data from ad7747
        Wire.write(0x01);             //set address point to capacitive DAC register 1

        Wire.endTransmission();       //pointer is set so now we can read the data

        Wire.requestFrom(0x48,3);     //reads data from cap DAC registers 1-3

        while(Wire.available()){
          unsigned char hi,mid,lo;      //1 byte numbers
          long capacitance;            //will be a 3byte number
          float pf;                    //scaled value of capacitance
          hi=Wire.read();
          mid=Wire.read();
          lo=Wire.read();
          capacitance=(hi<<16)+(mid<<8)+lo-0x800000;
          pf=(float)capacitance*-1/(float)0x800000*8.192f;
          Serial.print(pf, DEC); //prints the capacitance data in decimal through serial port

          Serial.print(",");
       }
       Serial.println();
    }
    delay(1000);
}