Features: Ultrasonic SR04 distance measuring transducer sensor module. SR04 consists of ultrasonic transmitter, receiver, and control circuit. When triggered it sends out a series of 40KHz ultrasonic pulses and receives from an object. Convenient to used and easy to wire, power with DC5V. It is one of the most widely used ultrasonic modules with stable performance and accurate measurement distance. Specifications: Power Supply: 5V DC Quiescent Current: less than 2mA Level Output: High 5V Level Output: Low 0V Effectual Angle: less than 15° Detection Distance: 2cm-4500cm Resolution: 0.3cm Size: 4.6*2.7cm/1.8*1in Quantity: 4pcs Weight: 10g(approx.) Instruction: Wiring Method: VCC, trig (control end), (receiver end),GND One control port sends a >10US high level, and receiver end waits to receive high level output. As soon as there is output, it can start timing, and read timing value when this port becomes low level, and this is the measured time for calculating distance. Repeat these steps to achieve motive measuring. Principle: (1)Using IO trigger measuring distance, give at least 10us high level signal. (2)Module automatically send eight 40 kHz squarewave, automatically detect if there is signal back. (3)When there is signal back, IO outputs a high level, the continuing time of high level is ultrasonic time from sending to responding. Detection Distance=(high level time*sound speed)/2; sound speed:340M/S Package Includes: 4 x Ultrasonic Sensor Modules 1、Ultrasonic SR04 distance measuring transducer sensor module. 2、SR04 consists of ultrasonic transmitter, receiver, and control circuit. 3、When triggered it sends out a series of 40KHz ultrasonic pulses and receives from an object. 4、Convenient to used and easy to wire, power with DC5V. 5、It is one of the most widely used ultrasonic modules with stable performance and accurate measurement distance.