Ultrasonic Distance Sensor HC-SR04

Sensor Features:

• 20mm - 5000mm Ultrasonic sensing distance
• 3mm positional accuracy.
• 5V Supply Input
• All processing done onboard and a single output pin returns a pulse-width proportional to object distance.
• Works by sending a 40kHz pulse and measuring the time for the pulse to be 'reflected' by an object, then using the speed of sound(~340m/s in air) the distance can be calculated.

The 4 Pins are as Follows:

• 5V Supply
• Trigger Pulse Input
• Echo Pulse Output
• 0V Ground

Technical Specifications:

• Operating Voltage :5V DC
• Quiescent Current : <2mA
• Effectual Angle: <15°
• Ranging Distance : 2cm – 500 cm
• Resolution : 0.3 cm

Using this with an arduino is quick and easy, all you need to do is provide a pulse to the trigger input pin and then measure the high time of the output pin and apply the following formula:

Distance = ((Duration of high level)*(Sonic :340m/s))/2

Datasheets: https://www.electroschematics.com/hc-sr04-datasheet/

Additional Resources:

https://bitbucket.org/teckel12/arduino-new-ping/wiki/Home

http://www.instructables.com/id/Simple-Arduino-and-HC-SR04-Example/

https://docs.google.com/document/d/1Y-yZnNhMYy7rwhAgyL_pfa39RsB-x2qR4vP8saG73rE/edit#

http://arduinobasics.blogspot.co.za/2012/11/hc-sr04-ultrasonic-sensor.html