An IO device for your feet: http://christian.gen.co/walkie-sockie/

WalkieSockie.ino

// WalkieSockie
// Christian Genco: @cgenco
// An alternate input/output device for the feet

// pins
static int pressurePin = A5, vibratorPin = 11;

// thresholds
static int pressureLow = 0, pressureHigh = 1000, 
  vibeLow = 0, vibeHigh = 255;

boolean smooth = true;
static int threshold = pressureHigh/2;

void setup() {
  vibratorPin = 9;
  pinMode(pressurePin, INPUT);
  pinMode(vibratorPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(pressurePin);
  if(smooth){
    analogWrite(vibratorPin, map(sensorValue, pressureLow, pressureHigh, vibeLow, vibeHigh));
  }else{
    boolean crossedThreshold = sensorValue > threshold;
    digitalWrite(vibratorPin, crossedThreshold ? 1 : 0);
  }

  Serial.println(sensorValue);
  // Serial.println(map(sensorValue, pressureLow, pressureHigh, 0, 255));

  // Serial.println(sensorValue);
  delay(100); // delay in between reads for stability
}