I love this!  It's an excellent problem to solve. That's crazy that 40% less blind people can read braille.  Nice that someone is trying to solve this problem.  Also, the idea of a mechanical output for text is very interesting to me.

I have posted many more videos of the different approaches I tried over the years... look at my channel.  It might save you time not making the same mistakes I made!

Hello,  I must commend you on the excellent work you have done! We seem to be following the same path.  These are some links to some videos where I demonstrate some Braille Display mechanisms - including a similar common latch mechanism. The actuators are different. I also have a single line version that works quite well!  The refresh is mechanical - lower cost.

Any updates or word on this?  I recently got involved with a family with a blind child and I must admit that I was taken aback by the cost of these machines.  I immediately started thinking of how I could "hack" something together, and then ran across your HAD page.  Looks like you have already done a lot of ground work, and I'd love to help where I can.  I might start something of my own, but as I tend to get half way through and then run out of time/energy/money/something else I really would rather team up with someone.

This is a really cool project. I had a couple thoughts, based on my observations working with my mother's visually impaired students.

1. A lot of blind children get *really* good at typing on normal keyboards. One kid I am working with is a faster typist than *I* am, and I've been typing for almost 20 years longer than he has. It might be worth it to forget adding a keyboard in favor of building the display (at least for the short term), while allowing for a user to plug in an external keyboard of their own (with which they will likely be much more familiar)

2. Unless I'm misunderstanding something (have read through the whole page, though mostly very quickly) it looks like you want to be able to detect touches on the display. This is a great idea, but one I feel is less important than you might think. While one would think a blind person could hit a hyperlink on their display (maybe by pressing a button on the side and then tapping lightly, or double tapping, the link text), in practice, it might be better to just have some functionality to cycle through hyperlinks in web documents (or specific sections within documents) and then select them to follow the link. Though, maybe some combination thereof would be better, I'm not sure.

I don't know how much access you have to people who are visually impaired, so I'd be happy to ask the ones I know any questions you might have. I assume, however, that you're doing this *specifically* because you know someone who is visually impaired, so maybe I can just help by providing a larger sample size.

Anyway, this got a bit long. This is a great project! If you've made any progress in the past four months, let us know!

It's impressive that blind persons can read braille, I have tried to feel the difference between the bigass braille dots that usually are on the buttons in a lift - but I can't really feel anything at all.

But are the blind equally sensitive to small heated regions? I.E could they read braille dots that are made out of warm and cold regions instead of raised dots? Is so one could build a solid-state non-moving braille display....

just saw this this morning. http://www.ibtimes.co.uk/blitab-worlds-first-tactile-tablet-ipad-blind-1508042

If you accept suggestions, I strongly recommend a different approach: just use a mechanism like the Zuse's Z1 mechanical memory. The idea would be to use a basic cell like this one:

The red dots are just cylinders that can be in one of both positions. Over each "bit" will be a "dot" that will be up when the cylinder is in one position or down when the cylinder is in the other position. This can be done easily if the dot is like a wedge.

The interesting thing about this idea is that this cell can be repeated in 2D and each one connected to its neighbors; this allows to control X*Y dots with just X+Y solenoids (or whatever you want to use). Even more: the side with more bars can be multiplexed, in order to use log2 solenoids and reducing further its count.

Also, the cells are built with just metal sheets, which are very cheap and easy to create.

Great idea! I have some ideas to throw into the mix:

Use a 2x3 array of micro solenoids on a sled (like a CD tray ejecting) moved to each character via a hobby servo. Put a light sensing diode in the middle of each character so the sled knows that char has been read and can race behind updating the next bit of data. That way refresh rate would not really matter. Stretch a piece of latex or something similar over top of everything to give it a nice smooth yet defined surface.

Hi Trevor

Thanks for the feedback, I'm actually useing the 8 dot Braille standard as it is better for science, but I get your point. Your idea is interesting, but maybe a bit to complex for me. I am using single bar of steppers (I couldn't find solenoids cheap and small enough) and setting them as an entire row, so 4 steps is an entire line of text, with each line resettable on its own. It would be much better if I could reset each character on its own, but the mechanics would be too fragile. If I can prove the concept, I can refine it in later versions.

Great idea. It is true that disabled people does not have an easy life.

As I understand, you want to use the same mechanism as the pen. It means a spring for every digit.

May I suggest to use a system like in the computer keyboard as spring. Small rubber stuff.

I hadn't considered a membrane, I will look at the feasibility for my scale.

I understand, but I think how to bring it to big and cheap... :o)

Keep on the your prototype.

I meant component size, would it fall apart because its too small? I've had so much feedback in the last day or so I'm almost having to completely redesign before I have even started :) Thanks for the support, always looking for new ideas.

will be cool to see where this goes.

Brilliant Idea!