MA40A3 with two ultrasonic parking sensor distance sensor circuit settings VR1, VR2 potentiometer can do this with a direct 12-volt car battery from the circuit can work with buzzer provides audible warning Ultrasonic Analog Parking Sensor Project sorce Electronics Projects, MA40A3R Ultrasonic Parking Sensor Circuit (analog desing) "analog circuits projects, " Date 2019/08/02