How Ultrasonic Sensors Work? How do ultrasonic distance sensors work?

Electronics Curiosities September 04, 2019

                         How Ultrasonic Sensors Work







Pins

  • Vcc pin is given to + 5v
  • Trigger pin is for control
  • Echo is for receiving
  • The ground is connected to negative



Ultrasonic sensors are based on the principle of reflected sound waves and are used for measuring distance. Sound waves are generated by the ultrasonic sensor (transmitter) and they’re reflected and collected by the receiver if there is an object in front of it. After detecting sound waves it measures the time it takes between transmitting and receiving those sound waves. Distance is then estimated by the time interval between sensor and object.


The range at which Ultrasonic Sensor is working between 2CM to 4M The sensor provides stable non-contact distance measurements from about 2cm to 4 meters with very high accuracy. It is easily interfaced to any microcontroller.



Description


Used for measuring distance, object sensing, motion sensing, etc.

The module sends eight 40Khz square wave pulses and automatically detects whether it receives the returning signal. If there is a signal returning, a high-level pulse is sent on the echo pin. The length of this pulse is the time it took the signal from the first triggering to the return echo.


The performance of the ultrasonic sensor distance measuring module is stable and measures the distance accurately.


Features of Ultrasonic sensor



  • The working voltage is 5V DC.
  • The static current is less than 2mA.
  • The output signal is in the form of an Electric frequency signal,   high-level 5V, low-level 0V.
  • The sensor angle is not more than 15 degrees.
  • Detection distance is in between 2cm-450cm.
  • High precision Up to 3mm.
  • Stable performance.
  • Accurate distance measurement.
  • High-density.



Working



  1. Provide the IO trigger supplying at least a 10us sequence of the high-level signal.
  2. The module sends eight 40khz square waves and automatically detects whether receive the returning pulse signal.
  3. If there is a return signal the output level will be high and the high time of the signal is the time from transmitting to receiving.
  4. The ultrasonic sensor has a transmitter and Receiver. The HC-SR04 ultrasonic sensor uses the principle of SONAR to determine the distance to an object.
  5.  Its operation is not affected by sunlight.


The Trigger and the Echo pins are the input-output pins of this module and hence they can be connected to the input-output pins of the microcontroller. When the receiver detects a return wave the Echo pin goes high for a particular amount of time which will be equal to the time taken for the wave to return to the sensor.




Thank You

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