The 2023 entry film
Hackaday Prize 2023
Three and a half minutes on how the cell works, made for the entry that won. About 140,000 views.
A Braille cell built from printed parts.
Refreshable Braille displays cost thousands of dollars, so most Braille readers never own one. This cell replaces the costly piezoelectric actuator with a printed cam and a magnet.
Grand Prize, 2023 Hackaday Prize
The refreshable Braille module
About 10% of blind people read Braille, and the price of the hardware is a large part of why.
In a commercial refreshable Braille display, each cell costs $100 to $150, because every dot is driven by a piezoelectric bimorph. The cells alone for a forty-cell display come to $4,000 to $6,000.
This module replaces the actuator with an eccentric cam carrying a 1mm by 0.5mm rare-earth micromagnet. A small coil flips polarity, the cam rotates between two positions, and the pin rises or drops. Once it is up, the geometry holds it there: the weight of a reading finger cannot push it back, so a static page draws no power at all.
The housings are SLA printed. The coils are 50 micron enamelled copper wound on ferrite cores with a winding tool that is itself 3D printed. Peak draw is 1W while a single pin actuates, and adding ferrite cores took the refresh from 200ms per pin down to 50ms.
The raw materials come to about one dollar a cell. The module won the Grand Prize in November 2023. A team of eight built it, and the project is published in full: build logs, CAD, circuit-board files and the bill of materials. It has been viewed more than 103,000 times.
Watch it explained.
The Hackaday Prize entry film: how the cell works, in three and a half minutes.
Scale
Three cells, one hand
The boards that carry the coils. Each one is a single Braille cell.
Assembled
One module
Housing, coils and board together.
Printed
Straight off the build plate
Resin housings on supports, before cleaning.
Mechanism
The parts that move
Cams, followers and cell bodies, mid-revision.
How it works.
Four parts per dot. The cam carries the magnet, the electromagnet turns the cam, and the geometry holds the pin where it was put.
The module running.
Ten years on one problem
The module that won in 2023 is my third attempt at the problem.
The first version was published in 2016, with Paul D'souza. It used vibration motors from mobile phones, with the eccentric weights replaced by shaped cams, to push the pins of a printed cell up and down. Hackaday covered it that April, and the design reached the semifinals of the 2016 Hackaday Prize.
It worked, but it was too expensive and too slow. We scrapped the mechanism and redesigned it around micromagnets, and that version won in 2023.
It started earlier still. As a student I demonstrated an early Braille display prototype to Dr A.P.J. Abdul Kalam at Srujana in Hyderabad. The Hindu later ran the photograph.
2016
The first cell
Printed, pinned, and small enough to hold between two fingers.
Scale
Next to a two rupee coin
A whole cell, barely longer than the coin is wide.
2023
The module that won
The same size as the first cell, with a new mechanism and no piezoelectric parts.
Driver
Eight cells on one board
The evaluation board, for testing cells together.
In the press.
Unlike commercial units, which use expensive piezo-electric actuated pins, his design utilizes an array of tiny electromagnets to rotate even tinier cams.
Only about 10% of blind people around the world can read Braille. One primary reason is the high cost of Braille displays.
If you work on Braille, I want to hear from you.
