LinkSprite infrared roadblock sensor uses an integrated infrared transceiver. 74LS00 is used to construct a resonator. Adjust the potentiometer can adjust the frequency of the infrared light to be the center of receiver, i.e. 38kHz. Now the receiver is of highest sensitivity. Adjust the other potentimeter can adjust the transmit intensity to meet the requirement of sensing distance.
The ballback working distance is longer than 20cm.
There are four pins: enable, output signal, power, ground. Jumper can be used to always enable. When there is object/roadblock in front of the sensor, the LED will turn on, and the out signal will be HIGH.