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Blind Walking Stick Using Arduino & Ultrasonic Sensor HC-SR04

There are millions of disabled people in this world who are always in need of helping hands. Independent mobility reduces the dependence on caregivers.  Disabled people always find themselves challenging to go out  independently because of their physical deficiency or inability to move in a  normal fashion.  People with visual impairment face many challenges in their daily life as modern assistive devices often do not meet consumer requirements in terms of price and level of assistance. 

This project teaches us how to create a blind walking stick using an Arduino board and an ultrasonic sensor called the HC-SR04. According to a recent WHO report, about 30 million individuals are blind. Since they are unable to walk alone, these blind persons are entirely reliant on others. We created the Blind Walking Stick technology to help blind individuals walk easily and independently for this purpose. Two or three ultrasonic sensors can be added to this project for further aid and accuracy.

Components Required:

  • Arduino UNO Board
  • HC-SR04 Ultrasonic Sensor
  • Buzzer
  • 9 Volt Battery
  • Switch (Optional)

HC-SR04 Ultrasonic Sensor

The HC-SR04 is a distance sensor that uses ultrasonic waves. With a range accuracy of up to 3mm, this inexpensive sensor provides non-contact measurement functionality from 2cm to 400cm. An ultrasonic transmitter, a receiver, and a control circuit are all included in the HC-SR04 module.

Ultrasonic Sensor HC-SR04 uses sonar to measure the distance of the object. It emits an ultrasonic wave at 40 kHz which will go and bounce back after hitting an object. By knowing the time traveled and the speed of the sound, we can calculate the distance (speed=distance/time). Ultrasonic waves are much faster than regular sound and as humans, we won’t be able to hear them. (Some animals and fishes like dolphins and bats are able to use it for communication and seeing in the dark).

PINOUT OF HC-SR04 ULTRASONIC SENSOR:

  • VCC: +5 V supply
  • TRIG:  Trigger input of the sensor. The microcontroller applies a 10 us trigger pulse to the HC-SR04 ultrasonic module.
  • ECHO: Echo output of the sensor. Microcontroller reads/monitors this pin to detect the obstacle or to find the distance.
  • GND: Ground

FEATURES:

  • Sensor Type: Ultrasonic
  • Output: Digital Sensor
  • Voltage: 5VDC
  • Operating Current: 15mA
  • Measure Angle: 15°
  • Ranging Distance: 2cm – 4m
  • Static current: < 2mA
  • Level output: high-5V
  • Output Signal:5V
  • High Precision: Up to 2 mm
  • Input Trigger Signal: 10µs TTL impulse
  • Echo Signal: Output TTL PWL Signal
  • High sensitivity ultrasonic range sensor
  • Works with Arduino board

Circuit: Blind Walking Stick Arduino Ultrasonic Sensor

Make the following connections as shown in the connection diagram below to create a Blind Walking Stick using Arduino and an Ultrasonic Sensor HC-SR04.

Blind Walking Stick Using Arduino & Ultrasonic Sensor HC-SR04
  • Vcc pin of HC-SR04 is connected to 5V pin of Arduino
  • Trigger pin of HC-SR04 is connected to D12 pin of Arduino
  • Echo pin of HC-SR04 is connected to D11 pin of Arduino
  • The ground of HC-SR04 is connected to the GND pin of Arduino.
  • The 9-volt battery’s positive terminal is connected to the Arduino’s Vin pin, and its negative terminal is attached to the GND pin.
  • Between the Arduino’s D9 pin and the GND pin, there is a buzzer connected.

Circuit & Working:

The major goal of this project is to make it easier for blind individuals to move and to alert them when their path is blocked by impediments. a buzzer is used as a warning signal, whose frequency of beeping changes depending on how far away an object is. The frequency of the buzzer beeps will increase as the obstruction gets closer.

The Ultrasonic Sensor HC-SR04 is the key part of this device. A high-frequency sound pulse is transmitted by the ultrasonic sensor, which then determines the best timing to catch the signal of the sound echo reflecting back. Ultrasonic waves are sent through one of them, which also serves as the transmitter. The sound signal that is echoed is picked up by the other, which serves as a receiver. The sensor is calibrated using the airborne sound speed. In the air, sound travels at a speed of 341 meters per second, and the distance between a sensor and an object is determined by multiplying the passing time by the sound speed and dividing the result by two.

Distance = (Time * Speed Of Sound) ÷ 2

After measuring the distance, Arduino uses a buzzer to create a beep format. When the distance is high, the frequency of the beep decreases, and when the distance is low, the frequency of the beep increases.

Source Code/Program:

First, download the Ultrasonic Sensor Library Ultrasonic Sensor from here and add the library to Arduino IDE. Then compile and upload.

Download Ultrasonic.h library



int buzzer = 9;

#include <Ultrasonic.h>

Ultrasonic ultrasonic(12,11);

void setup() {
Serial.begin(9600);
pinMode(buzzer,OUTPUT);
}

void loop()
{
int distance = ultrasonic.Ranging(CM);
if (distance<50){
int dil = 2*distance;

digitalWrite(buzzer,HIGH);
delay(dil);
digitalWrite(buzzer,LOW);
delay(dil);
}
}

CONCLUSION:

I hope you have understood how to design Blind Walking Stick Using Arduino & Ultrasonic Sensor HC-SR04. We MATHA ELECTRONICS will be back soon with more informative blogs.

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