Shopping Aid for the Visually Impaired

Designers: Nupur K. Modi and J. Brent Ratz
Client Coordinators: Dr. Henry A. Greene, Assoc. Prof. of Ophthalmology, UNC
Supervising Professor: Dr. Larry N. Bohs

Over 200,000 people in N.C. alone are blind or visually impaired. Many of these people can read newspaper-headline-sized print or larger. For these people, grocery shopping is not only inconvenient, but also potentially dangerous since they have trouble reading labels on food packages. Many of these people have medical conditions, which make it essential for them to be aware of nutritional facts and ingredients.

Our Shopping Aid for the Visually Impaired (SAVI) provides this information in a large, easy-to-read manner. SAVI consists of a laptop computer and barcode scanner secured to a typical shopping cart. After the user scans a product’s barcode, the laptop uses the UPC number to access a corresponding data file. The item name, its price, promotional information, the ingredients, and nutritional facts are displayed in a standard format. Large buttons on the keyboard allow the user to scroll through all of the information or to jump directly to a desired heading. Keys for variable magnification, color reversal, and audio feedback of the product name and price are also provided. An additional feature lists the items in the cart and displays the running price total, while allowing products to be added to or deleted from the list.

How this project helped
For many people, a product’s ingredients, nutritional content and price are the major influences in a purchasing decision. As a result, visually impaired individuals may be limited to purchasing only they items they already know about or they may have to have some one else do their shopping for them. In addition, knowing the amounts of certain nutrients or certain ingredients, can be crucial for someone with a medical condition or special dietary needs. In addition to the direct health implications of the device, greater independence will be achieved. As Dr. Henry A. Greene, Associate Professor of Ophthalmology at the University of North Carolina points out, “They lose their ability to drive, and hence to control their lives. Their vision loss makes it hard for them to derive the information required for them to make their own decisions, including what they eat. This device will afford them an ability to retain or regain at least some level of independence.”

The Shopping Aid for the Visually Impaired can be broken down into two major components: the computer programming and the mounting system. Computer programming includes all of the code used to enter, access, and display the product information. The programming can be separated into the Customer-interface (what the visually impaired person accessing the information uses) and the Data Entry Page (what the store employee entering the information uses). Because both facets of the programming require a great deal of user interaction and graphical display, Java is the programming language of choice, as it is well regarded in both areas.

Before an item is available to be scanned by the customer, the information for that product is entered by a store employee using the back-end user-interface. The barcode is used as the name of the file where the product information gets stored and will be written to the variable UPC. Once the customer obtains the device from customer service they are greeted with the "Welcome" page. The device then waits for the user to press a key or scan an item. If the user is not familiar with the device, brief instructions and key descriptions are available when the down arrow is pressed at the start-up screen.

The scanner works by entering the number written below the barcode (the     decoded UPC). The program recognizes when a single digit is entered and concatenates that number to the end of the UPC variable, which is a string. Because the scanner automatically concatenates the ASCII code for the “Enter”; button at the end of the UPC number, the program can read a barcode of any length. Once the program recognizes the “Enter” code, it reads the file to which the UPC variable points (the same file that was constructed using the Data Entry page).
The information in the file is written to the variables in the Customer-interface (product, price, gram, percent, ing, abbrev, etc.) that are currently unassigned.

Before making a decision, the user may view the item’s nutrition facts, ingredients, or a list of the items currently in the cart by pressing the N, I, or LIST button, respectively. The magnification feature is programmed to allow the user to choose between 75pt, 100pt, or 120pt font  sizes. The REVERSE COLORS button toggles back and forth between white-on-black and black-on-white. In addition to these features, audio output is also available for the product name and the price by pressing the HEAR PRODUCT/PRICE button (yellow speaker). At any time after the first scan this button plays a .wav file (constructed using the Windows Sound Recorder) that returns the product name and the price.

The mounting system consists of a cover, designed to replace the standard laptop keyboard with 11 large buttons, and a base plate, which is permanently mounted to the cart and serves as a platform for the laptop computer and the laser scanner. The cover is constructed from 1/16″ sheet metal. Two side brackets mounted to the cover piece lock the laptop in place. Small pad-locks keep the cover down once the laptop is in place. In addition, the cover has areas cut out to allow for the scanner plug and the buttons from a large button telephone. These buttons provide a mechanical link to selected buttons on the laptop keyboard.

The total cost of this project was approximately $400.00.

Comments are closed.