Lesson 25 Ultrasonic Ranging Module

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The ultrasonic sensor uses sound to accurately detect objects and measure distances. It sends out ultrasonic waves and converts them into electronic signals.

Required Components

1 * Raspberry Pi

1 * Breadboard

– 1 * Ultrasonic ranging module

– 1 * 4-Pin anti-reverse cable

Experimental Principle

This sensor works by sending a sound wave out and calculating the time it takes for the sound wave to get back to the ultrasonic sensor. By doing this, it can tell us how far away objects are relative to the ultrasonic sensor.

Test distance = (high level time * velocity of sound (340M/S)) / 2 (in meters)

Experimental Procedures

Step 1: Build the circuit.

Raspberry PiGPIO Extension BoardUltrasonic Ranging Module

For C Users:

Step 2: Change directory. 

    cd /home/pi/SunFounder_SensorKit_for_RPi2/C/25_ultrasonic_ranging/

Step 3: Compile.

    gcc ultrasonic_ranging.c -lwiringPi

Step 4: Run.

    sudo ./a.out

For Python Users:

Step 2: Change directory. 

    cd /home/pi/SunFounder_SensorKit_for_RPi2/Python/

Step 3: Run.

    sudo python3 25_ultrasonic_ranging.py

Now you can see the distance between the ultrasonic ranging module and the obstacle (like your palm) in front on the screen. Sway your hand over the ultrasonic ranging module slowly and observe the distance printed on the screen.