HC-SR04 ultrasonic sensor / ultrasonic range / ultrasonic module / Arduino car

The main technical parameters:
1. use voltage: DC5V
2. quiescent current: less than 2mA
3. level output: high 5V
4. level output: low 0V
5. induction angle: no more than 15 degrees
6. detection range 2cm-450cm
7. high accuracy: up to 3mm
Connection mode, VCC, trig (control), echo (receiving end), GND ground wire

This product uses method: a control mouth sends a 10US above high level, can wait for high level in the receiving port.
Output can open the timer, when the mouth into a low power usually can read the value of the timer, this time for the ranging time,
Can calculate the distance. So constant cycle measurement, you can achieve the value of your mobile survey ~ ~ ~ ~ ~ ~

Module working principle:
(1) a IO trigger ranging is used to give at least a high signal of 10us;
(2) the module automatically sends 8 40KHz Fang Bo to automatically detect whether a signal is returned;
(3) a signal is returned, and a high level of the high level is passed through the IO output.
The time of the ultrasonic wave from the launch to the return. The test distance = (the high level time * sound velocity (340M/S)) /2;