Pot+Arduino

 #include <SPI.h>
         int myBits[256] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,
                            31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,
                            59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,
                            87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,
                            112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,
                            134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,
                            156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,
                            178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,
                            200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,
                            222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,
                            244,245,246,247,248,249,250,251,252,253,254,255,};

      int myBitspot[256] = {105,108,111,114,117,120,123,126,129,132,135,138,141,144,147,150,153,156,159,162,165,168,171,174,177,
                            180,183,186,189,192,195,198,201,204,207,210,213,216,219,222,225,228,231,234,237,240,243,246,249,252,255,
                            258,261,264,267,270,273,276,279,282,285,288,291,295,299,302,306,309,313,316,320,323,327,330,334,337,341,
                            344,348,351,355,358,362,365,369,372,376,379,383,386,390,393,397,400,404,407,411,414,418,421,425,428,432,
                            435,439,442,446,449,453,456,460,463,467,470,474,477,481,484,488,491,495,498,502,505,509,512,516,519,523,
                            526,530,533,537,540,544,547,551,554,558,561,565,568,572,575,579,582,586,589,593,596,600,603,607,610,614,
                            617,621,624,628,631,635,638,642,645,649,652,656,659,663,666,670,673,677,680,684,687,691,694,698,701,705,
                            708,712,715,719,722,726,729,733,736,740,743,747,750,754,757,761,764,768,771,775,778,782,785,789,792,796,
                            799,803,806,810,813,817,820,824,827,831,834,838,841,845,848,852,855,813,817,820,824,827,831,834,838,841,
                            845,848,852,855,859,862,866,869,873,876,880,883,887,890,894,897,901,904,908,911,915,918,922,};

const int slaveSelectPin = 10;
long int val;
int analog_sensor = A0;
int i;

void setup()
{
  pinMode (slaveSelectPin, OUTPUT); // Slave Select como Output
  SPI.begin();
}

void loop()
{

  for (i = 0; i < 256; i++)
  {
    analog_sensor = analogRead(A0);

    if ( (analog_sensor >= myBitspot[i]) && (analog_sensor <= myBitspot[i+1]) )
    {
      val = myBits[i];
    }

     digitalPotWrite(val);
  }

}

void digitalPotWrite(int value) {
  digitalWrite(slaveSelectPin,LOW);
  SPI.transfer(0x11);
  SPI.transfer(value);
  digitalWrite(slaveSelectPin,HIGH);
}