Hackaday Prize Entry: MOLBED Braille Display

Electromechanical braille displays, where little pins pop up or drop down to represent various characters, can cost upwards of a thousand dollars. That’s where the Modular Low-cost Braille Electro Display, aka MOLBED, steps up. The project’s creator, [Madaeon] aims to create a DIY-friendly, 3D-printable,  and simple braille system. He’s working on a single character’s display, with the idea it could be expanded to cover a whole row or even offer multiple rows.

[Madeon]’s design involves using Flexinol actuator wire to control whether a pin sticks or not. He designed a “rocker” system consisting of a series of 6 pins that form the Braille display. Each pin is actuated by two Flexinol wires, one with current applied to it and one without, popping the pin up about a millimeter. Swap polarity and the pin pops down to be flush with the surface.

This project is actually [Madeon]’s second revision of the MOLBED system. The first version, an entry to the Hackaday Prize last year, used very small solenoids with two very small magnets at either end of the pole to hold the pin in place. The new system, while slightly more complex mechanically, should be easier to produce in a low-cost version, and has a much higher chance of bringing this technology to people who need it. It’s a great project, and a great entry to the Hackaday Prize.

12 thoughts on “Hackaday Prize Entry: MOLBED Braille Display

  1. It’s a shame the solenoid approach didn’t work out; I remember reading about it last year and really appreciating how small the form factor would be. I’m glad to see this project is still going though!

    1. Without dissing this particular project, I looked very deeply into building a braille system like this a couple of years ago, and consulted several vision impaired people and caseworkers about possible solutions.

      The big issue is speed of change. It’s straightforward to make something that pops up to make a braille character, it’s quite another to make that happen quickly enough to be useful to a blind user.

      Existing braille readers have a [text] line of piezo-electric embedded vibrating cylinders, and the reader passes their fingers left to right across a line of text. Their fingers touch any character very briefly – much less than 1/10 of a second.

      Shape memory alloy isn’t all that fast, and if the actuator in the project can’t change fast enough then this won’t be all that useful.

      This is a worthy project and probably could be done on the hacker level for much *much* less than commercial units, but I don’t think the chosen technology is a good match to solve the problem.

      1. On the subject of critiquing the project, I note that this is the 2nd iteration attempt.

        Even though I think the chosen technology is wrong, I also think that persistence and experience is key in making a successful project. It’s the people that keep trying different solutions over and over that eventually find the solution.

        The project has worthy goals, and I’ve always thought that braille readers could be made better and more cheaply than they are.

      2. But then , if he can build a page-sized “display” of said pins, the upper part could start updating when the person is past the middle of the page. Or, when the reading person get to the end of the page and press the “Next” button, some kind of signal ( a little beep, perhaps ) would indicate the page has been refreshed.

  2. Nice project, if it were a simple task than there would be better options around already.

    The high-end commercial piezoelectric based units are not waterproof, and can have >200 volt output drivers to the read elements under the pins.
    Its design has always annoyed engineers of all fields, but management tends to favor larger projects. We had hopped tactile display technology would become a consumer product, but it never became a popular idea:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4150388/

  3. Looks like the picture is of the old system. BTW, reversing the current to SMA wire does not reverse the motion. I believe he would need to turn the piece of wire on at one end of the rocker and the piece at the other end of the rocker off to “flip” the rocker. Overall I don’t like the approach. I think a latching electromagnetic device would be the way to go. A strong solenoid to set it and a weaker one to release it. The advantages would be it would not be temperature sensitive as SMA wire, and it would retain the last status with no power applied.

  4. I think the problem here is more that if the pins are held with stray electromagnetic force only, the blind person will not be able to read the text as he will push down the pins when reading them (think like quantium mechanics, reading it will also change it). Theres not a lot of force in those small electromagnets.

    There must be some locking system that “locks” the pin in its current position after it has been set. Best accomplished would be a small plate with 6 keyholes, and then grooves on the pins, both in their upper and lower position. After the pins have been set, the plate is actuated which will then lock the pins in its current position.

  5. Why not have a solenoid actuate a mechanism like a retractable ball point pen?
    Pulse once to extend, pulse again to retract, it’s reliable, compact, rapid and needs no power to maintain either state.
    The fact that the mechanism is inexpensive enough to use in cheap pens means it might work well for this purpose.

    Click click click click click click

  6. Madaeon should look into using voice coil actuators for the pins.

    they’re easily to make by hand, easily to control and have the added benefit of the faster they move the more force they can produce. which could come in handy for a project like this i believe.

  7. I saw a thing on diginfo ages ago where some Japanese inventor made a braille thing that was the fraction of the cost and could be mass produced. And now I’m wondering if he used the same wire.
    Tried to find it but I failed.

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