Smart Walking Cane for the Blind

Vidya G
5 min readJan 15, 2020

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Vidya G | VIT Chennai | July 2019

Introduction

Visually impaired people are the people who can’t identify smallest detail with healthy eyes. Those who have the visual acuity of 6/60 or the horizontal extent of the visual field with both eyes open less than or equal to 20 degrees, these people are considered blind. Such people are in need of aiding devices for blindness related disabilities. Around 10% of blind have no usable eyesight at all to help them move around independently and safely. The electronic aiding devices are designed to solve such issue. To record information about the obstacle’s presence in a road, active or passive sensors can be used. In case of a passive sensor, the sensor just receives a signal. It detects the reflected, emitted or transmitted electro-magnetic radiation provided by natural energy sources. In case of using an active sensor, the sensor emits a signal and receives a distorted version of the reflected signal. It detects reflected responses from objects irradiated with artificially generated energy sources. This kind of active sensors are capable of sensing and detecting far and near obstacles. In addition, it determines an accurate measurement of the distance between the blind and the obstacle.

There are many reasons to design a smart stick for blind; firstly, the blind to feel free, isn’t surrounded by wires as in belts and its content. Secondly, is easy to use because it is familiar and affordable. Thirdly, to be able to detect obstacles that exist on the ground (this is not available in glasses), which he walks indoor and outdoor is faced by obstacles such as stairs, puddles and sidewalks.

Fig 1: Smart Walking Cane with Arduino Uno

Here is a project that presents a smart walking stick based on Ultrasonic sensors and an Arduino controller for visually impaired people and we accomplished this goal by adding ultrasonic sensor at specific position to the cane that provided information about the environment to the user by activating the buzzer sound.

The stick is capable of detecting all obstacles in the range 4 meter during 39 ms and gives a suitable respect message empowering blind to move twice his normal speed because she/he feels safe. The smart stick is of low cost, fast response, low power consumption, light weight .

Project Description:

1. Arduino: The digital and analog input/output pins equipped in this board can be interfaced to various expansion boards and other circuits. Serial communication interface is a feature in this board, including USB which will be used to load the programs from computer.

2. Vibrator Motor: It is a compact size coreless DC Motor used to informs the users of receiving the signal by vibrating, no sound.

3. Buzzer: A buzzer or beeper is an audio signalling device, which may be mechanical, electromechanical, or piezoelectric (piezo for short). Tt voltage is 5v DC supply

Software

1. Arduino IDE: You will be needing Arduino IDE software to write and upload the programming logic onto the Arduino Uno board

2. Programming language: C/C+ +Language

System Flow Chart and Circuitry

Vibration Motor

This is the type of DC vibration motors used in mobile phones. It requires a voltage supply of 3V to 5V with current around 125 mA. This type of motors can be programmed to control its speed by using the PWM (Pulse Width Modulation) method. The PWM signal is generated from the TMR2 timer via interrupt control on RC2 and RC1 pins to gate this PWM to active the vibration. The diameter of the motor is 0.5 cm and the thickness is 2.5mm.

Water Sensor

Water sensors available are used to detect water levels inside tanks are very expensive. Our objective is to detect water existence regardless its level. So we used a costless alternative. Two wire probes fit at the bottom of the stick to sense obstacle like water pits, puddles and water spread. Once wires touch water, the circuit is shorted, this interrupts the microcontroller, activates the vibration motor and play warning message saying: “Attention there is water”.

Obstacle Detection Unit

· The three sensors used for obstacle detection, the step sensor and the depth sensor are ultrasonic sensors. Ultrasonic sensors have been used due to their high precision within a short distance and resistance to external disturbances such as vibration and electromagnetic interference.

· In this device, the HC-SR o4 ultrasonic sensor has been used, which has a detection range of 2–400cm

· Abd viewing angle of 15 degree. It can determine the distance of obstacles with an accuracy of 3mm, making it perfectly suited for outdoor environments.

· It is energy efficient, having an operating voltage of 5v and drawing a maximum current of 15mA

· The distance of the obstacle from the user is calculated using the formula

D=v X t

· Where D is the distance of the obstacle in m,v is 330m/s, which is the speed of the ultrasonic wave in air, and t is the time duration in seconds for which the Echo signal from the sensor remains high.

Puddle Detection Unit

· A water level sensor can be used to detect puddles in the user’s path.

· The sensors occupy a compact surface area of 60mm+20mm and has a detection area of 40mmx16mm.

· The device has been programmed to trigger a response when the water level reaches 1cm, so that false triggers are not given in the case of water droplets falling on it due to light rain.

· Feedback for the water detector has been given through symbolic commands through the Braille/Morse output.

Left , right and front haptic buzzer at the cane holder

Conclusion:

The Smart Stick acts as a basic platform for the coming generation of more aiding devices to help the visually impaired to be safer. It is effective and affordable. It leads to good results in detecting the obstacles lying ahead of the user in a range of four meters, detecting stairs and water pits. This system offers a low-cost, reliable, portable, low-power consumption and robust solution for navigation with obvious short response time. Though the system is hard-wired with sensors and other components, it’s light in weight. Further aspects of this system can be improved via wireless connectivity between the system components, thus, increasing the range of the ultrasonic sensor and implementing a technology for determining the speed of approaching obstacles. While developing such an empowering solution, visually impaired and blind people in all developing countries were on top of our priorities.

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Vidya G
Vidya G

Written by Vidya G

Former ML Intern , Ericsson | OB, IEEE Computer Society VITC | COMSNETS2020 Find more @ www.vidyaganesh.com

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