Refreshable Braille Displayfor Teaching Geometry toVisually Challenged

Mar 29, 2019

by Michael Abrams

Prabal Goyal Department of Mechanical Engineering Indian Institute of Technology, Delhi

The IT revolution in the last two decades has made information available in a quick and cheap way. All students may find themselves challenged in today's fast moving and globally competitive environment, but students who are blind or visually challenged have additional difficulties. Every blind student needs to possess the same levels of information processing and manipulation skills as their classmates and keep developing them with the changing needs. For this they need advanced technologies, both hardware and software, to become literate in the modern world. This access is made available to them through a wide range of special devices and software, referred to as assistive technology [1]. These innovative technological tools allow them to access information effectively.

But, some other issues keep these products away from the intended users. Most of them suffer from very high cost such that they are not even close to being affordable to the blind people. Also, user-friendliness is another area where these tools need to be improved to make them successful in the market. Some of the products presently available are very complex to learn and use for the visually challenged.

According to WHO [2], "… There are 45 million blind people in the world and 90 % of them live in the developing and less developed countries…". The income in these countries is so low that they cannot even afford a white cane. Also, the literacy rate of blind children in most of the developing countries is less than 10% [3]. These facts make it clear that there is an urgent need to develop simple, low-cost and user-friendly devices to serve the vast population of visually challenged people living around the world.

A Refreshable Braille Display is a tactile device consisting of a row of 'soft' cells. A soft cell has 6 or 8 pins made of metal or nylon. The pins are controlled electronically to move up and down to display characters as they appear on the display of the source system - usually a computer or Braille note taker. Various Braille Displays have been developed over the past few decades. One of the first developments was the Braille Slate and Stylus system (Figure 1(a)), which is still used by blind people to read and write Braille text. But, over the years with the changing requirements of the users there has been a shift towards Refreshable Braille Displays. The first form of Refreshable Braille Display used mechanical actuation of array of pins to provide character realization. Thereafter, electro-mechanical displays (Figure 1(b)) were developed where various actuation mechanisms were used to provide the refreshable property to the Braille cells. Further attempts were made with Electro-active polymers, Shape Memory Alloys, Motor based actuators but none of the products was commercially used.

Figure 1: (a) Braille Slate & Stylus (b) Refreshable Braille Display (Source:

Refreshable Braille Displays have been well studied for several years, but there is tremendous scope for product improvement. The product being developed is a step towards it as it would have most of the improvements required in the presently available products in the market. Some of the improvements have been listed below:

  • Better Functionality: Multiple Line Display
  • Cheaper Technology: Low Cost Actuation Mechanism
  • Good Refreshing Rate: Fast Response
  • Flexible Design: Extendable to Larger Matrix of Braille pins.

In the project, a prototype has been developed using 5X5 array of electro-magnetic actuators. This prototype was integrated with the computer to take up input image, process it and produce tactile output. The concept can be extended to larger grid sizes which can be used for full page displays. In the prototype, low-cost electromagnetic actuators have been used which makes the concept simple and easy to develop further.

The product will enable visually challenged people to realize patterns other than simple characters. Therefore, they will be able to process complete information i.e. simple text as well as images from digital documents.

Figure 2: Pattern Realization with the developed Braille Display



1. Assistive technology for students who are Blind or Visually impaired: A Guide to Assessment, Ike Presley and Frances Mary D'Andrea, AFB Press, 2008

2. Vision 2020: The Right to Sight. 2010. Blindness and Visual Impairment: Global Facts.