Though I have just recently begun my adventures with Arduino, I have learned a lot. So here are a few tutorials where I explain the projects I have done in detail.
The Security Sensor
This is a small project that I worked on to gain familiarity with the distance sensor. I used a ping sensor to record how long it took for a wave to hit an object and come back. I then divided that value by two (one for the way there and the other for the way back) and multiplied it by the speed of sound to get the distance of the object. When the distance read by the sensor is within a certain amount, the beeper will sound and the frequency between the beeps increases as the object gets closer. Once I got this to work I placed it in front of my door and sat back and relaxed as it managed to annoy every single one of my family members as they attempted to enter my room. My mother, in effort to make it drive me insane as well, eventually decided to place something in front of the sensor to make it beep continuously. I solved this issue by having the beeper turn off once the object is within 10cm of the sensor. I placed it in front of my door to alert me when anyone has entered my room.
Taptic: A helping hand to aid the visually impaired
This is a project that I worked on with fellow Harker Seniors Roshni Pankhaniya and Neil Movva. We entered it in the Technology Students Association States Competition and won second place!
Introduction, Engineering Design Goal
This report describes a student project developed with the goal of creating an assistive device targeted to the visually impaired. Though blind users are a very prevalent market, unlike other disabilities blindness has seen very little innovation, and modern technology has not been sufficiently applied to it. We hope to benefit not only blind users but those who are visually impaired as well and we intend on doing so by connecting these people to their environments in a simple and easy to use manner. Innovations like braille and the walking cane allowed them to read and better sense their environment through tactile sensory feedback. Although they did make the lives of the visually impaired easier they still lack a sense of depth perception that is key in perceiving their environment accurately. We aim to reproduce the functionality normally realized by a cane with a compact “Haptic Range Finder”, a device that would measure immediate distance and report this data to the user through intuitive vibration patterns, i.e. haptic feedback. Furthermore, we hope that our design can provide greater freedom of mobility and potentially greater resolution in a visually impaired users’ interpretation of his/her surroundings. The document outlines the process of design and development we implemented, starting from use cases, which served to develop requirements and specifications, user interface design and development using User Centered Design methods [5], architecture and implementation. For overall project management we used SCRUM [4] engineering development methods, meeting regularly to iterate, revise and develop the application. We used an AVR 8-bit microcontroller to serve our processing needs.
Use Cases
Our design is driven by use cases, which serve to develop basic requirements and specs, then functionality and UI mockups. General context is that the user/actor is visually impaired. The User may or may not be familiar with using a cane to help them perceive their environment.
Crossing the Street
When a user crosses the street they must be able to sense the distance of obstacles clearly in order to maintain their safety and be more aware of their surroundings. This must be accomplished by developing some means for them to differentiate between near and far objects in a precise manner. It is equally crucial for them to be able to identify far cars as well as other humans that may be crossing with them.
Walking around their home
When at home the user needs to be able to wear the glove and still maintain use of all their fingers so that they can still perform their daily activities like reading braille and eating etc. They also need to be able to wear it for extended periods of time which require the glove to be reasonably breathable and comfortable. The sensor should be removable and fit to the size of the hand and once the sensor is removed the glove should be washable.
Crossing the Street
When a user crosses the street they must be able to sense the distance of obstacles clearly in order to maintain their safety and be more aware of their surroundings. This must be accomplished by developing some means for them to differentiate between near and far objects in a precise manner. It is equally crucial for them to be able to identify far cars as well as other humans that may be crossing with them.
Walking around their home
When at home the user needs to be able to wear the glove and still maintain use of all their fingers so that they can still perform their daily activities like reading braille and eating etc. They also need to be able to wear it for extended periods of time which require the glove to be reasonably breathable and comfortable. The sensor should be removable and fit to the size of the hand and once the sensor is removed the glove should be washable.
Specifications
Functional specifications (functions the product offers) and non-functional specifications constraints on the product) are developed from use cases.
The product shall have the following major functionality:
Functional Specifications:
The product shall have the following major functionality:
Functional Specifications:
- Perceivable change in vibration to convey distance of object to user.
- Product should fit on the user’s hand relatively comfortably.
- Light Weight
- Flexible
- PCB should be of relatively small size
- Glove should not increase perspiration on palm.
- Glove should allow hand to breathe.
- Should not interfere with normal day to day hand movements.
- Only pinky finger is required, all other fingers remain open and available for use.
- Should be very easy and intuitive to use without too much training.
Development Approach
We began by considering the use of sensors in reading a user’s environment. As implied in our design goals, we identified “distance data,” i.e. the measurement of proximity to obstacles, to be the most pertinent information to present to a blind user. We sought a compact sensor that would report relatively accurate distances at short to medium range (2 to 200cm) and, after some consideration, settled on an ultrasonic rangefinder. This small device transmits and receives inaudible 60kHz sound waves; by timing the round-trip travel of each sound pulse, we can use the speed of sound to calculate distance.
To convey the proximity of obstacles, we implemented two motors operating on vibrational frequency. Since the fingers are the most sensitive part of the body, one motor was placed on the fingerprint of the pinky finger; the other was placed on the base of the wrist. The motor on the wrist vibrates to let the user know that the object is farther than 100cm away; when the user crosses the 100cm boundary, the fingertip motor begins to vibrate. The fingertip motor vibrates at an increasing frequency the closer the person is to the object. The shift allows the user to distinctly feel a change and understand the distance of objects to a larger degree of accuracy. The motors allow the user to detect obstacles within 350cm.
To convey the proximity of obstacles, we implemented two motors operating on vibrational frequency. Since the fingers are the most sensitive part of the body, one motor was placed on the fingerprint of the pinky finger; the other was placed on the base of the wrist. The motor on the wrist vibrates to let the user know that the object is farther than 100cm away; when the user crosses the 100cm boundary, the fingertip motor begins to vibrate. The fingertip motor vibrates at an increasing frequency the closer the person is to the object. The shift allows the user to distinctly feel a change and understand the distance of objects to a larger degree of accuracy. The motors allow the user to detect obstacles within 350cm.
Engineering Design and Elements
We began the design process on a regular circuit board. The design proved to be bulky and didn’t have much stability on the surface of the hand. We sought a better layout for the glove, and moved to a printed-circuit board (PCB). The pcb allowed us to use both sides of the copper board, eliminating the need to use jumpers and drastically reduced the size of the board, to better fit on the surface of the hand. We also implemented a smaller battery, to reduce the weight on the board and by extension the hand.
We first designed the PCB on a program called Fritzing [1]. We then printed the layout onto photo paper, which would allow for easier transfer of the toner. The toner was transferred onto a piece of copper using heat and pressure applied via an iron. The excess paper was then removed, and any holes in the marking were filled in with Sharpie. The masked copper board was then placed in the etchant solution (HCl) for approximately 10 minutes until all the unmasked copper had been etched. The toner was then removed using steel wool. The holes on the layout were drilled using a 1/32 drill bit and we then soldered the individual components in place.
We first designed the PCB on a program called Fritzing [1]. We then printed the layout onto photo paper, which would allow for easier transfer of the toner. The toner was transferred onto a piece of copper using heat and pressure applied via an iron. The excess paper was then removed, and any holes in the marking were filled in with Sharpie. The masked copper board was then placed in the etchant solution (HCl) for approximately 10 minutes until all the unmasked copper had been etched. The toner was then removed using steel wool. The holes on the layout were drilled using a 1/32 drill bit and we then soldered the individual components in place.
Future Steps
We are also looking to incorporate a two axis accelerometer and gyroscope combination to recognize movement of the glove. For example, if the user shakes their hand from side to side the glove should switch on or off. The accelerometer measures acceleration and can be used to measure the tilt of the glove, and the gyroscope measures the speed of rotation (a.k.a the angular rate) and reads zero when absolutely still. Since both sensors tend to drift and we must use both of them to accomplish our goal of recognizing and performing actions based on movements made by the user, we intend on using the Kalman filter [2] to combine the data returned by the two relatively noisy sensors and produce clean accurate measurements.
In addition we intend on transitioning to a polyimide board [3], which with its greater flexibility will allow the board to better fit on each individual user’s hand.
In addition we intend on transitioning to a polyimide board [3], which with its greater flexibility will allow the board to better fit on each individual user’s hand.
Conclusion
This is a high school project and was developed over the course of little more than a year. The first prototype was designed by Neil and the later revisions are the fruits of collaborative effort between all three of us. We currently have a working design and have successfully tested it on our friends and family. We are in the process of adding a gyroscope and accelerometer, two functions which while not essential to measuring object proximity, definitely add to the environmental depth perception the user obtains as well as recognizing movements of the user. As the final step of our process, we are working towards directly testing the glove on those visually impaired.
Acknowledgements
We would like to thank our parents for their support and encouragement throughout this entire endeavor, and especially for driving us around and helping us get supplies.
In particular we want to thank them for taking time out of their schedules, advising us and being a fantastic support system as we cracked our heads over multiple hurdles in an effort to create a product that will effectively aid visually impaired users sense their environment through vibration.We also want to thank our friends for being our first test subjects and giving us critical feedback that only made us better and helped us think out of the box as we designed the initial stages of the product.
In particular we want to thank them for taking time out of their schedules, advising us and being a fantastic support system as we cracked our heads over multiple hurdles in an effort to create a product that will effectively aid visually impaired users sense their environment through vibration.We also want to thank our friends for being our first test subjects and giving us critical feedback that only made us better and helped us think out of the box as we designed the initial stages of the product.
References
[1] Fritzing
[2] Introduction to the Accelerometer, Gyroscope and Filters:
Colton, Shane, Mentor, FRC 97. "The Balance Filter: A Simple Solution for Integrating Accelerometer and Gyroscope Measurements for a Balancing Platform."25 June 2007. TS.
[3] Flexible Circuit
[4] SCRUM: An iterative and incremental agile software skeleton for managing software projects and application/product development, it enables the development of verbally communicative, disciplined and self-organizing teams.
[2] Introduction to the Accelerometer, Gyroscope and Filters:
Colton, Shane, Mentor, FRC 97. "The Balance Filter: A Simple Solution for Integrating Accelerometer and Gyroscope Measurements for a Balancing Platform."25 June 2007. TS.
[3] Flexible Circuit
[4] SCRUM: An iterative and incremental agile software skeleton for managing software projects and application/product development, it enables the development of verbally communicative, disciplined and self-organizing teams.
