HC-SR04 consists of ultrasonic transmitter, receiver, and control circuit. When trigged it sends out a series of 40KHz ultrasonic pulses and receives echo from an object.
Power Supply: DC 5V, Quiescent Current: less than 2mA; effectual angle: less than 15°; distance: 2cm-500cm.
Compatible with DIY Robot Car/Raspberry Pi 4B, 3B+, 3B