5PCS HC-SR04 Ultrasonic Distance Module Distance Measurement Transducer Sensor for Arduino Use the IO TRIG port to trigger telemetry. We need at least 10 high level signals. The module can send out 8 pro 40kz square wave automatically and will check if any signal is returned. If any signal is returned, output high level signal through IO ECHO port. The duration of the high level signal is the time between the transmitter and the reception with the ultrasound. Test distance = duration of the high level * speed of sound (340 m / s) / 2 Static current (max): 2mA; electrical output level: 5V high; Detection distance: 2cm-450cm; High accuracy: 2mmModule Main Technical Parameters:Working Voltage: 5V (DC)Static current: less than 2mA.Output signal: electric frequency signal, high level 5V, low level 0V.Sensor angle: no more than 15 degrees.Sensing distance: 2cm-450cm.High precision: up to 0.3cmInput trigger signal: 10us TTL pulseEcho signal: TTL PWL output signalConnection mode: VCC / trig (T) / Echo (R) / GND (VCC 5V supply and GND is the ground wire. TRIG is the trigger control signal input, ECHO is the echo signal output.)Quantity: 5PC Package Content:HC-SR04 5X Ultrasonic Module Distance Measuring Transducer Sensor For Arduino Note: The data are all manual measurement, please allow 1-3cm error, due to The light and display difference, there will be some color difference, depending on the physical object received.