The Braille writing system, created and named after Frenchman Louis Braille, was first published in 1829 and quickly became the most commonly used tactile writing system among blind people. It is a very practical system when written on paper, but it hasn’t been easy to adapt to refreshable “displays” in our digital world. Many devices have been built over the years to produce refreshable Braille writing, but they usually rely on many small physical actuators that are expensive and prone to failure. That’s why a team of researchers from Germany’s Bayreuth University have developed a device called HaptiRead that can produce Braille using ultrasound waves.
Ultrasound is any sound save with a frequency too high for humans to hear — over 20 kHz for most people. Other than that, ultrasound waves behave exactly like any other sound wave. That means that ultrasound waves can be felt as they move the air but not heard. If you put your finger near an active ultrasound transducer, you should be able to feel a light touch similar to a gentle breeze. That can only be felt in the direction that the transducer is pointing, which means it can be focused. The HaptiRead device relies on that fact in order to create Braille-like patterns that can be felt when you move your hand in front of the transducers.
The HaptiRead device contains a total of 256 ultrasound transducers that are arranged in a 16 x 16 grid on its front face. A Leap Motion Controller gesture sensor is used to detect when a user moves their hand in front of the device. The ultrasound transducers are then activated in the correct patterns and sequences to produce the writing. The HaptiRead device could be substantially more reliable than typical electromechanical refreshable Braille displays. An additional benefit is that it doesn’t require physical contact, which is an important consideration in our post-COVID-19 world if the display is going to be used in public. HaptiRead would give blind people the ability to read any digital text, including from websites and even eBooks.