• Motor Port is on with full power
• Read from Sensor Port using Light Sensor Block

// Read FAST GP2D12 Sensor output and displays 
// raw value on RCX display (requires RCX 2 firmware)
// Connect Sensor wire to Motor B
// Mount Sensor on Port Sensor A


int value;

task main()
{
  SetUserDisplay(value,0); // Display "value" on LCD
  OnFwd(OUT_B); // Power Motor B 
  SetSensorMode(SENSOR_1,SENSOR_MODE_RAW);
  SetSensor(SENSOR_1,SENSOR_LIGHT); // Active mode: 

  until (false)
  {
    value=SENSOR_1; // reads and display value
    Wait(5); // for 50 ms
  }
}

• Power consumption 30mA.
• Range: 10cm to 80cm.
• Use as a LEGO light sensor.
• Can be read once in 35 ms in normal operation mode.
• Can be read continuously for any amount of time.
• More sensitive and with more usable range.
• Works with Active Sensor Multiplexer
• Works with GP2D12 or GP2D120