The IR Seeker V3 detects IR signals from the HiTechnic IR Beacon or IR ball and by using two detectors it calculates the direction to the signal source.
The relative signal strength from left and right looking detector are combined to create approximate direction readings. These readings are simultaneously taken for both the 600Hz and 1200Hz beacon and ball frequencies. Direction readings to the left of center are negative, to the right of center are positive and dead ahead are zero.
The IR Seeker V3 I2C bus address of 0x38.