Design and Development of Smart Blind Stick for Visually Impaired People

Blindness is a condition in which a person loses their ability to see because of physiological or neurological issues. This paper suggests a smart blind stick that uses modern technologies to make traveling easier for visually impaired people. Ultrasonic, light, water, and height sensors are used in the blind stick. An ultrasonic sensor is used to identify obstacles ahead of blind people. In addition, water sensors detect the presence of water and leaks when deployed in regions. One ultrasonic sensor is placed on the walking stick to classify the height of a barrier. An LDR is used to provide information about day and night. It also has GPS to help blind people track their location. Furthermore, a voice recognition system was employed to deliver the message by the human voice. Its height can be adjusted easily. After understanding customers’ demands, some ideas are added to create a product prototype. A cost analysis has been conducted, and it is discovered that mass production of the product is quite profitable. The smart blind stick is a low-cost, fast, and easy solution for blind and visually impaired people in third-world countries.


Introduction
Visually impaired people have trouble seeing even the smallest details with healthy eyes.With both eyes open, those with a visual acuity of 6/60 have a horizontal width of the field of vision less than or equal to 20 degrees.These people are thought to be blind [1].According to a World Health Organization survey, there are approximately 285 million visually impaired people worldwide, with 39 million blind and 246 million having poor vision.Developing countries are home to nearly 90% of the world's visually impaired people [2].Blindness is a curse for people experiencing poverty and those who live in remote rural areas since they need assistance to work outside and perform other everyday tasks.This paper describes a system that aims to free people from the curse of blindness by making them self-sufficient in their day-to-day tasks.Visually impaired persons cannot lead their lives in the same manner as normal people.Every step of the way to their destination, they need support.They face trouble identifying stairs or obstacles while using a conventional blind stick.The white cane is still a common walking aid used by the majority of blind people, especially when they are outside.As a result, more accidents occur because it is challenging to recognize stairs or obstructions [3].This study focuses on designing and creating an intelligent blind stick that will make it easier for blind people to navigate using advanced technology.1305 (2024) 012032 IOP Publishing doi:10.1088/1757-899X/1305/1/012032 2 Tirupal et al. proposed an ultrasonic sensor-based stick using four ultrasonic sensors with Arduino Mega fixed to the stick.The ultrasonic sensor uses a Bluetooth module to detect the object.It transmits the information to the Arduino, which responds to the client by vibrating or sending an order [4].Olanrewaju et al. suggested a stick named iWalk, which has ultrasonic and water sensors to detect obstacles and water ahead.The water sensor activates a different buzzer if it detects water.The system also has a wireless RF remote control that produces a sound when pressed, which helps to locate the stick if it gets misplaced [5].Kunta et al. proposed a stick that can send a message alerting others to the user's whereabouts.The user can change the phone numbers to which an alert message could be delivered with the help of an application.A soil moisture sensor is attached to check whether the surface is moist [6].After observing the previous models of the smart blind stick, it can be concluded that many studies have been conducted on this walking stick innovation, with various design implementations such as infrared sensors, radio signals, and ultrasonic sensor detection.In this paper, the design of a walking stick is proposed to make a simple, efficient, and flexible electronic guiding system for blind and visually impaired people to aid their mobility regardless of their location, whether outside or indoors.This study aims to create a smart blind stick that is economical and effective for most blind people, as well as being light in weight.

Scopes of Smart Blind Stick
The earliest form of a navigation tool for blind people has been in the form of a walking stick.However, the lack of required skills, expense, and training duration are the disadvantages of using it.Through technological advancements, it is now possible to design and create specialized solutions that can assist a visually impaired individual in navigating freely.As a result, the smart blind stick suggested in this paper will help visually impaired people resolve their issues.Hospitals, public health organizations (National Society of the Blind and Partially Sighted-NSBP), non-governmental organizations (Blind Education and Rehabilitation Development Organization-BERDO), nursing homes, and retail stores were defined as critical markets for primary research.

Survey Findings
A Google Forms survey was conducted to ascertain the public's opinion of a typical blind stick.The survey demonstrates that the majority of respondents do not believe traditional walking sticks are appropriate for blind people and instead prefer the smart blind stick.Feedback was received from 75 people who took part in the survey.Some of them are illustrated in Figure 1.

Quality Function Deployment
The technique for determining customer needs and converting them into detailed plans for creating items that meet those criteria is called quality function deployment (QFD).The voice of the customer refers to these expressed and implicit customer needs or expectations.This customer requirement knowledge is then organized into a "house of quality" or product planning matrix [7].These matrices translate higher-level "what's" or needs into lower-level "how's"product specifications or technical features to satisfy such needs.Quality Function Deployment helps maintain a correct focus on valid requirements and reduces misinterpretation of customer needs.As a consequence, QFD serves as a valuable collaboration and planning tool.The House of Quality for Smart Blind Stick is depicted in Figure 2. Some general requirements for smart blind sticks, such as ease of use, affordability, lightweight, and lifetime, are contrasted with technical concepts, such as the material used, weight, availability, efficiency, etc.The importance rating, relative weight, and customer competitive assessment determined through group discussions are also displayed here.The circle is defined as strong, the filled circle as moderate, and the downward triangle as weak, and the ratings of the Likert Scale of 9-3-1 are the relationships of several symbols.Furthermore, the direction of improvement-upward triangle as maximize, rectangular as target, and downward triangle 3 as minimize are shown in the table.The cost of the equipment and the material used are strongly related to affordability in the diagram.At the same time, availability is only moderately associated with affordability because affordability does not directly affect availability.The relationship between fundamental and technical customer requirements is also established in this manner.Then, using a few symbols, technical correlations are also demonstrated.For example, the relationship between the material used and weight is highly positive, and thus, if we choose heavy material, the weight will also increase.The same theory also applies to other relationships.

. Main Body Parts
The body of the product (Figure 3) contains a Handle, Frame, Control Board, Battery, and Stopper.This product has a handle that can be grasped and manipulated by hand.A conventional walking stick forms the mainframe of the device, upon which ultrasonic sensors are mounted at appropriate locations.The control box contains switches, sensors, etc., for turning on/off the automated features.The device is lightweight and is powered by a rechargeable LiPo battery (9V), which generates electrical energy for the product.This product uses a rubber stopper with remarkable stability, making unwanted sliding out of position practically impossible.

Energy Conversion
Batteries, which provide electrical energy are the most common power sources for wireless sensor nodes.Several ultrasonic sensors and Arduino Nano are used in this project for various functions.The ultrasonic sensor works by producing high-frequency sound waves and analyzing the echo that is returned to it.To assess the situation, the sensor analyses the echo.The microcontroller receives this signal and determines which output should be triggered [8].Then, the output is processed to earphones, where the electrical energy is converted to sound energy, as shown in Figure 4.

Sensing System
The sensing system of the product (Figure 5) comprises sensors, earphones, and LDR.The sensor converts the physical action to be measured into an electrical equivalent and processes it so that the electrical signals can be easily sent and further processed [9].It can output whether an object is present or not present (binary) or what measurement value has been reached (analog or digital).Earphones have current flowing through them.The loop's electric current interacts with a permanent magnet, which drives the air, resulting in sound.A photoresistor or light-dependent resistor is sensitive to light.
When light falls upon it, the resistance changes.Values of the resistance of the LDR may change over many orders of magnitude, with the value of the resistance falling as the level of light increases [10].

Working Principle
The suggested smart blind stick system's flowchart shows each step a blind person takes while walking (Figure 7).Additionally, it displays the Arduino Nano control process and the work of the sensors.

Used Materials and Processes
The weighted average method is used to determine materials and the best approach (Table 1 and Table 2) to manufacture various parts of the Smart Blind Stick.Manufacturing techniques that reduce production costs, metallurgical changes, and material waste while meeting most criteria are selected.

Cluster Function Structure
The step-by-step procedures for each function are detailed in the cluster function structure (Figure 8).Switches receive electrical energy from the control board.The sensor will get power when the switch is turned ON.After the sensor has served its purpose, it sends a signal to the transmitter and receiver (RF module).Here, the radio frequency transmitter will pick up the signal and pass it through the receiver.The signal is then transformed into sound energy by the Arduino Nano microcontroller after leaving the receiver.Earphones can be used to hear sound.

Cost Analysis
The total fixed cost of the stick is 96,57,874 Tk per year.Considering the selling and administrative expenses, the total production unit per year is 2,100.The variable cost for 2,100 products in the first year is 4,680 Tk.Using these values and the break-even formula, we calculated the break-even quantity of 7,223 units for the first year.That means total income equals the entire cost if the sales number is 7,223 units.It is possible to make a profit when sales reach 7223 units, as depicted in Figure 9.The break-even period is around three years and five months.

Design Analysis
A crucial step before we build the product is design analysis.A product's functionality and operation are also decided through design analysis.A 3D model of the device was created by SolidWorks software.Then, the product model was simulated in three dimensions, and an additional study was conducted to enhance this product.Through design analysis, it was possible to replicate our product and identify its flaws [11].The product design has undergone extensive simulations and analysis before being made ready for production.

Figure 10. 3D model of Smart Blind Stick
Stress analysis is crucial because it helps determine whether a certain structural design can handle the expected internal and external forces and stresses.Load analysis for static components and stress, strain, and displacement analysis for moving components were determined.A force of 23.698N was applied to the stick [12].For stress analysis of the walking stick made of Aluminium (Figure 11), Yield Strength (6.204×10 8 ) is 216 times the Von Misses Stress (2.873×10 6 ) obtained, indicating that the design is considerably safe.Strain and displacement profiles (Figure 12 and Figure 13) were also analyzed to optimize design and predict potential failures in the product.

Object Detection
The ultrasonic sensor was tested; the results are shown in Table 3.The system performed as intended at a reasonable distance from the user.The voice guidance lets the user know if there are any obstacles in their path.

Water Detection
The outcome of the water detection that protects the user from walking into stationary water in the environment is shown in Table 5.The transistors will activate the voice alarm system once the walking stick is placed into deep water.Average percentage of success of the tested device 86.78%

GPS
People with vision impairments frequently lose their stick.Both the GPS & and GSM modules are functional, capable of sending messages and providing the user's exact location.GPS is added to navigate the location of our blind stick.Thus, they can easily find their stick with the help of others.Location tracker GPS (37V, 1.5A) was used to see the location of the stick with the help of Google Maps on the smartphone.The users will first send "000" to the GPS's installed sim number.A link will be delivered to them in response, as shown in Figure 15.

Conclusion
The smart blind stick serves as a precursor to a new era of assistive technology that will allow the visually impaired to explore indoors and outdoors safely.It is both strong and sensible.It produces excellent results in detecting obstacles in the customer's path within a two-meter range.This system provides a simple, reliable, flexible, low-power, and robust route solution with a noticeable rapid reaction time.Although the framework is densely packed with sensors and other components, it is relatively light.Remote availability between framework segments can be used to improve different sections of the framework, extending the range of the ultrasonic sensor and realizing an innovation for determining the speed of moving approaching obstacles.Additionally, a servo motor for ultrasonic sensor rotation, a vibrator for feedback, and voice recognition can be included.
The device created for this project is ideal for detecting obstacles, water, height, and light.The smart walking stick's overall system has been improved using the Arduino Nano as its microcontroller.The microcontroller makes it simple to program the sensors and indicators.Many electronic sticks are available on the market nowadays; however, combining the additional features of assistive mobility with simple and low-cost technology would undoubtedly aid in capturing a much larger market in developing countries.

Declaration of Competing Interest
The authors declare that they have no known financial or interpersonal conflicts that might have influenced the research presented in this paper.

Figure 1 .Figure 2 .
Figure 1.Survey Findings (a) Suitability of Traditional Blind Stick (b) Necessity of Smart Blind Stick (c) Features of Smart Blind Stick (d) Usefulness of the Smart Blind Stick

Figure 3 .
Figure 3. Main Body Parts of Smart Blind Stick

Figure 7 .
Figure 7.The flowchart of the work of the proposed system

Figure 8 .
Figure 8. Cluster Function Structure of Smart Blind Stick

Figure 9 .
Figure 9. Break-Even Analysis of Smart Blind Stick

Figure 14 .
Figure 14.Prototype of Smart Blind Stick

Table 1 .
Selected materials for every part

Table 2 .
Selected processes for different manufacturing processes

Table 3 .
Distance Measurement Height was measured using an ultrasonic sensor, and the results are shown in Table4.Any height discrepancy will trigger a signal from voice guidance.

Table 5 .
Water Level Measurement

Table 6 .
Table 6 lists the total number of blind tests, how many of them were successful, and at what percentage.Number and Percentage of Succeeded Tests