Sensor HC-SR04 - ultrasonic distance measurement 2-400 cm

Ultrasonic distance sensor HC-SR04 for Arduino - 2cm to 400 cm

Description of the HC-SR04 sensor

Universal ultrasonic distance sensor operating from 2 - 400 cm. It is used to measure the distance to an obstacle, allows you to build alarm systems, robots, models, etc.

Special features of the HC-SR04 sensor

• Sensor commonly used to measure distance from obstacles (e.g., in autonomous robots)
• The output is a signal whose duration is proportional to the measured distance.
• Powered by 5 volts.
• Sensor is not susceptible to solar interference and object color.
• The sensor can be connected with any startup kit such as Arduino, or Raspberry Pi minicomputer.
• The leads are 2.45 mm goldpin connectors
• The HC-SR04 sensor is compatible with Arduino
• For the sensor we offer practical sensor holder

Parameters of the HC-SR04 sensor

• Supply voltage: 5 V
• Average current consumption: 15 mA
• Measurement angle 15*
• Measuring range: 2 - 400 cm
• Output: frequency signal
• Operating frequency: 40 kHz
• Dimensions: 45x20x15 mm
• raster connector 2.54mm
• The sensor itself supports a range of 2 to over 500cm, but is limited by the standard library to 300cm.

Important links

• Example of connection to Arduino
• http://www.arduino.com.en/projekty/ultradzwiekowy-czujnik-odleglosci-i-arduino/
• http://www.elecfreaks.com/244.html

Description of the leads on the HC-SR04 sensor board

VCC - power supply + 5V Trig - input signal to the sensor Echo - sensor response GND - power supply ground

Notes for connecting the sensor - How the sensor works

• To start the measurement, apply a voltage pulse (5V high state) to the TRIG pin for 10uS.
• The module measures distance using a 40 kHz sound wave.
• A signal is sent to the microcontroller in which the distance depends on the duration of the high state and can be calculated from the formula

• test distance = (high level time × velocity of sound (340m/s) / 2

• where:
• test distance - measured distance
• high level time - duration of high state
• velocity of sound - speed of propagation of sound wave in air - 340 m/s

In short, to get the result in cm, you can use the formula: distance [cm] = ( high level time [us] * 34 ) / 1000 / 2

The measurement procedure is shown in the figure below:

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