HC-SR04 ultrasonic sensor

The HC-SR04 Ultrasonic Sensor is a very affordable proximity/distance sensor that has been used mainly for object avoidance in various robotics projects . It essentially gives your Arduino eyes / spacial awareness and can prevent your robot from crashing or falling off a table. It has also been used in turret applications, water level sensing, and even as a parking sensor.

Feature:

• Model: HC-SR04
• Color: Blue + Silver
• Working voltage : 5V(DC)
• Static current: Less than 2mA.
• Output signal: Electric frequency signal, high level 5V, low level 0V.
• Sensor angle: Not more than 15 degrees.
• Detection distance: 2cm~450cm.
• High precision: Up to 3mm
• Mode of connection: VCC / trig(T) / echo(R) / GND
• Module Working Principle:
• Adopt IO trigger through supplying at least 10us sequence of high level signal
• The module automatically send eight 40khz square wave and automatically detect whether receive the returning pulse signal
• If there is signals returning, through outputting high level and the time of high level continuing is the time of that from the ultrasonic transmitting to receiving