[HN Gopher] Affordable Wheel Based Refreshable Braille Display
___________________________________________________________________
Affordable Wheel Based Refreshable Braille Display
Author : jacquesm
Score : 206 points
Date : 2024-03-16 08:52 UTC (14 hours ago)
(HTM) web link (jacquesmattheij.com)
(TXT) w3m dump (jacquesmattheij.com)
| gostsamo wrote:
| As someone blind, my two pens are that noise, power consumption,
| and fragility are things that could be compromised to a large
| degree. If I've had a braille display at school and uni, it
| would've helped with many of my math issues. If it works and it
| is cheap, it would be a big step forward for many people. Power
| is not that expensive compared to the current displays, noise
| could be mitegated or just powered through, and important stuff
| could be kept in good order. Money are harder to spend.
|
| Screen readers are perfect for plain text and gui navigation, but
| a multi dimensional object like an equation are easier to
| understand if you have your hands on it.
| nolist_policy wrote:
| I wonder if one could combine a low-fidelity braille display
| (maybe with heat or vibration (piezoelectricity)) with touch
| sensitivity and context-sensitive tts in response to
| touching/reading the display.
| magicalhippo wrote:
| I was curious about just temperature.
|
| From this pdf[1] it seems fingers have 3-5 cold sensing
| points per square cm, with cold sensing points being about
| 10x as prevalent as warm sensing points.
|
| So I was thinking about using a combination of a
| thermoelectric cooler[2] coupled to some thin metal rods,
| which have individually wound coils around them near the top.
| The rods would be mounted flush to allow touching all of them
| at once. The cooler would ensure the rods are normally cold,
| and the coils would provide induction heating.
|
| Thus by changing which coils are activated, the different
| rods would be either cold or not, and due to the active
| cooling and relatively low thermal mass should change state
| quite quickly. At least that's the idea.
|
| Though perhaps we just don't have enough sensitivity in our
| fingers to pick this up. And it wouldn't work well for a
| portable device due to power draw.
|
| edit: Found this[4] paper where they try a temporal method
| instead of spatial method to use temperature to convey
| information.
|
| [1]: https://web.as.uky.edu/Biology/faculty/cooper/bio350/Bio
| 350%...
|
| [2]: https://en.wikipedia.org/wiki/Thermoelectric_cooling
|
| [3]: https://en.wikipedia.org/wiki/Induction_heating
|
| [4]: https://www.mdpi.com/2306-5354/10/10/1156
| digdugdirk wrote:
| I love unique interface ideas, and this one definitely
| counts.
|
| What are your thoughts on how to account for the user's
| fingers heating up the interface rods? I'm imagining
| someone going back to read a previous character, and their
| fingers having essentially "reset" the character from body
| temp.
| magicalhippo wrote:
| This was just off the top of my head, but I imagined the
| thin rods having low enough thermal mass that the active
| TEC cooling would not cause fingers to significantly heat
| up the rods.
|
| That is, the TEC cooler should be able to relatively
| quickly lower the temperature after the finger is
| removed.
|
| Again, off the top of my head idea so no idea if it would
| work or not, but doing a quick viability check should be
| relatively easy and cheap.
| sitkack wrote:
| I have thought of a similar design, but little solenoids
| inject themselves into the cold path bridging the gap, the
| TEC would chill a huge thermal mass and then the individual
| rods could be chilled and heated rather rapidly.
| IshKebab wrote:
| Braille was designed for paper. Maybe there's an interface that
| is easier to actuate using motors if you don't absolutely require
| it to be Braille.
| mwcampbell wrote:
| Braille was designed by a blind person to be easily read by
| touch. Let's not throw that away. At the very least, an
| alternative tactile reading system needs to be designed by one
| or more blind people, not imposed by sighted people like the
| systems that Braille superseded.
| IshKebab wrote:
| I'm not sure what you're responding to here. Of course I
| wasn't suggesting making a system that is hard to read by
| touch. And it doesn't matter if the creator can see or not if
| it is better than the alternatives.
| eternauta3k wrote:
| I often wonder how much productivity we're leaving on the table
| by not making systems that are harder to learn but more
| efficient.
| Y_Y wrote:
| Do you use Dvorak or Colemak?
| paulftw wrote:
| why couldn't it be done on an off-the-shelf 28-byj-48 stepper?
|
| The reason is probably explained somewhere in the article, I just
| can't find where
| Joel_Mckay wrote:
| The 28-byj-48 were designed to oscillate air conditioner vents,
| and as such have an internal slip-clutch mechanism to add to
| the abysmal backlash of their gear box.
|
| There is also the weight and energy consumption to consider.
|
| People may be better off gluing a small bead to one side of a
| flip dot display. =)
| Kaibeezy wrote:
| Fantastic effort, but oddly and almost shockingly archaic. This
| is seriously the way the problem is being solved? Why isn't it
| microelectronics or MEMS? If we can print 3mm OLED pixels surely
| there's a way to lift a discrete 1.6mm dot, especially with that
| huge 2.5mm spacing. Even adjacent dots ought to be no big deal.
| Maybe a haptic kludge or grid of air pressure nozzles?
|
| I have a personal theory of invention that states: "If you
| thought of it, someone else thought of it." I'll go have a
| look...
|
| OK, an hour later, what about this Dot Pad? "Dot actuator" is
| micro mechanical? Looks like almost a product. Dig the groovy
| scroll-in-place presentation, wtf.
|
| https://www.dotincorp.com/page/31
| squigz wrote:
| Only PS12k! https://www.visionaid.co.uk/dot-pad
| lrasinen wrote:
| Seems to be PS12k, so not cheap:
| https://www.visionaid.co.uk/dot-pad
|
| I was thinking if the dots need individual actuators. I'm old
| enough to remember dot-matrix printers; take the print head but
| put slightly beefier pins on it, move it left and right and use
| it to push metal spheres up in a hour-glass shaped cavity, with
| springy walls in the center section.
|
| Obvious problems: how do you reset the spheres? And wear
| issues.
|
| Edit: You could replace the hourglass throat with a plug valve
| (shared between pins). Print head comes along, turns the valve
| open, pushes the necessary balls up, closes valve, moves to
| next column. Needs more mechanics per cell, though.
| Nzen wrote:
| Your desire sounds a bit like the fluid based,
| piezoelectronically pumped haptic display presented by Shultz,
| et al, in 2023 [0]. I can't speak as to whether these could be
| packed in enough. The video indicates they can make cells of
| 2mm wide.
|
| [0] https://www.youtube.com/watch?v=j_rErbhxNFM (4 minutes
| olejorgenb wrote:
| A more usable page:
| https://www.dotincorp.com/page/32?gbn2=DotCell
|
| Doesn't look like it's MEMS? Unless each individual cell is a
| MEMS, but that seems strange. Maybe MEMS devices can't generate
| sufficient force?
|
| "MEMS actuator braille" has many research hits, but no obvious
| product.
| ta988 wrote:
| They have a bunch of patents explaining the tech
| https://www.freepatentsonline.com/20240054912.pdf
|
| The device people say cost 12k does a lot more than just
| braille so that's not a fair comparison.
| mtsr wrote:
| The article is rather long and I didn't manage to read it all.
| But why wouldn't this be done like a lock, where the shape of the
| key determines how far (or in this case which) pins are pushed?
| That way, you never have to touch the rotating wheel directly.
|
| The key then would just be an internal wheel that rotates and
| pushes out the right pins. If it works for a lock, surely it
| would work for something with much less resistance?
|
| Edit: nvm, they discussed this and dismissed it, although I don't
| fully agree with the reason.
| mdorazio wrote:
| I love how "science fair" this writeup is.
|
| Personally, I would have looked at more options before going for
| the (rather large) motorized wheel route. Two that come to mind
| are reusing the ball-type powered typewriters from the 80s/90s
| since the balls had embossed letters and high-precision
| positioning already. A second is microfluidic displays, which
| cellphone makers toyed with for on-screen keyboard tactile
| feedback back in the early 2010s. And indeed a quick search shows
| that a University of Michigan team used exactly that for a
| braille display 8 years ago [1] and it's spinning out into a
| company now. The company that was working on this for "pop-up"
| touchscreens 10 years ago was Tactus [2]. On the
| electromechanical side, it looks like there's an open source
| movement already with some interesting results so far [3].
|
| [1] https://www.youtube.com/watch?v=0fIg4rI4cDw
|
| [2] https://www.youtube.com/watch?v=JelhR2iPuw0
|
| [3] https://www.youtube.com/watch?v=BXi1tG78AW4
| j-a-a-p wrote:
| Beautiful example of the innovation narrative that keeps CTOs of
| the largest companies awake at night. A (very) intelligent
| outsider, with pen and paper, computer, a 3D printer who lives
| where Aliexpress delivers. Meanders and bounces between theory,
| practice and sleep deprivation can come up with a disruptive PoC
| in a matter of weeks [0].
|
| I would really like this to work, and/or that it inspires others
| to make these braille readers affordable.
|
| [0]: the inspiration for this project started 48 days ago:
| https://news.ycombinator.com/item?id=39159476
| AndrewKemendo wrote:
| Not just any old guy but my good friend and our very own
| Jacques
|
| https://news.ycombinator.com/user?id=jacquesm
| donatj wrote:
| Dumb question. Could one instead go with some sort of inflatable
| system? Thin layer of plastic with some controllable channels.
| Inflate the individual dots? There was an early smartphone that
| had a system like this for tactile feedback, I don't know if it
| ever went into production.
| anfractuosity wrote:
| Very good question, just came across -
| https://www.pnas.org/doi/full/10.1073/pnas.2106553118 which
| seems designed for braille.
| mwcampbell wrote:
| Unless I'm missing something, this article seems to assume 6-dot
| Braille cells. But every Braille display I've ever worked with
| uses 8-dot cells; that standard is called computer Braille.
| HappyPanacea wrote:
| Considering the human finger is very sensitive to texture perhaps
| there is a material that change its texture in response to
| voltage?
| atoav wrote:
| Why not just use mechanically decoupled pins that vibrate with
| a smartphone vibration motor? You don't need texture if the
| thing vibrates.
| ta988 wrote:
| Cost and noise would make that extremely unpractical.
| atoav wrote:
| As opposed to the low cost texture changing material
| proposed?
|
| If I had to do this I'd probably look into PCB-based
| solenoids with compliant mechanisms. But there are already
| people working on that.
| persnickety wrote:
| Ctrl+F "dot matrix". Not found.
|
| How do printers manage to stick dots into paper? Is it similar to
| any of the ideas in the article?
| eirikbakke wrote:
| Another idea: Instead of actual tactile dots, use a voltage
| between two appropriately sized/positioned contact points, high
| enough to be felt by the fingertip, but not so high as to be
| uncomfortable. Then you just manufacture it as a regular PCB.
|
| (It would probably be required to multiplex the voltage between
| different dots, so that the finger current always flows within
| the small area of individual dots, rather than between dots.)
| ajb wrote:
| It might work, and it's an incredibly simple solution, but I'd
| want to check out if there is any chance of long term nerve
| damage. The user will be using it many hours a day nearly every
| day.
| jodrellblank wrote:
| Tiny pinpoint holes, blow air through them. Could you adjust the
| size of the holes and the flow of the air so you could feel them
| distinctly? If so, they could be backed by much larger, far away,
| valves without the mechanical parts needing to be so fine and
| precise.
|
| You only need to feel something, there doesn't need to be
| anything there - is it possible to have a voltage or capacitance
| charge or signal at a point which feels like a presence? "A
| smooth surface which feels lumpy" seems intuitively unlikely but
| stranger things have happened.
| ajb wrote:
| Yes, I was wondering if something could be done using 3d
| printed fluidic logic. If so then the entire thing could have
| no solid moving parts, and just be one big 3d print, except:
| (maybe) a single big rubber membrane in which dots are raised
| by fluid pressure. Plus of course the fluid pressure source;
| and the valves to interface the device to electronics, to input
| the display data. Otherwise it could be a big shift register in
| fluidic logic with an amplifier at each bit to output to each
| dot.
|
| The difficulty with fluidic logic is that the devices from the
| original flowering of the field don't work at the low Reynolds
| numbers found in smaller devices. Maybe something from the new
| micro fluidic field would work, but I don't know if they can
| control sufficient pressure to be felt, or to raise a rubber
| membrane.
| buu700 wrote:
| _" A smooth surface which feels lumpy" seems intuitively
| unlikely but stranger things have happened._
|
| I wonder how well it would work if you did something similar to
| Force Touch, but instead of one uniform trackpad it were
| separated into a matrix of small dots.
| contingencies wrote:
| Yes, you can do that but you still need a cheap valve with a
| size ideally smaller than one dowel pin 'cell' at standard
| braille densities. AFAIK this does not exist commercially, if
| it does it would be cost prohibitive, and therefore would need
| to be designed in some unknown manner focused on low
| fabrication cost. Since most valves operate based upon
| electromagnetism (solenoid-driven) you also have an electrical
| control problem. All in all, not an attractive solution path.
| jodrellblank wrote:
| The reason for suggesting that is because it wouldn't need
| tiny expensive custom delicate valves; connect the pinhole to
| a funnel which gets wider like the horns on this siren:
| https://stall.net/victorysiren/photo-
| pages/cars2/images/5SG-...
|
| then you can use whatever large, cheap, widely spaced, easy
| to access, easy to maintain, valves you can find. The trade
| would be size, noise, and power, but the gain would be easy
| to build, mass produced parts, easy to repair, large and
| solid and relatively reliable.
| contingencies wrote:
| Most valves are actuated by solenoids which use a lot of
| power. An array of them is not only physically huge but
| will exceed USB power availability at a count of one or two
| valves and you need many per braille block. Worse, you
| generally need to actuate huge numbers of them
| simultaneously. This approach is therefore difficult to
| consider for a real world deployment.
| cyanfrog wrote:
| woudn't grid of electromagnets work for this? spring loaded pin
| that gets retracted by the magnet?
| contingencies wrote:
| Commercially available electromagnets are too bulky, require
| too much power and are designed with generally physically
| unworkable assumptions around electrical interface types with
| respect to cost-effective manufacturing. In short the principle
| is sound, but the products are unworkable. Therefore, the coils
| must be integrated on-PCB to be cost effective.
| waltwalther wrote:
| I love the write-up! Everything is there, and it is a fascinating
| read even to a layperson (to braille tech). Thanks for sharing.
| dmazzoni wrote:
| FWIW, there's already a commercially available braille display
| that uses spinning wheels:
|
| https://bristolbraille.org
|
| Very interesting approach.
| ta988 wrote:
| That exact machine is discussed in the article...
| Retr0id wrote:
| A while back I made a (prototype) braille display with a similar
| concept but using linear sliders (per column) rather than a
| rotating wheel. Unfortunately I got side-tracked from the project
| and never figured out the best way to add actuators.
|
| I was proud of the fact that my design could be laser cut from a
| single sheet and assembled with no glue or fasteners (well, minus
| whatever mechanism would be needed to actuate the sliders)
|
| Image:
| https://retr0.id/media/38116918-4023-437b-9a48-d2ffb1d02dbf/...
|
| Short demo video:
| https://twitter.com/David3141593/status/1639261097252233220 (in
| the video caption I noted high friction, it was totally fine
| after sanding)
| thinking_banana wrote:
| please consider this reference https://inhabitat.com/ted-
| moallems-braille-it-labeler-is-mad...
| murkle wrote:
| Did that come to anything?
| ar-nelson wrote:
| A thought I had while reading this: what about putting a flexible
| membrane above the wheels (or belt) with the dots? This would
| require the user to press down to feel the dots, but it would
| remove the issue of fingers or hair getting caught in the wheels.
| devindotcom wrote:
| Very cool. I love seeing things like this being made. Some others
| from the past few years:
|
| https://techcrunch.com/2017/05/05/blindpads-tablet-makes-vis...
|
| https://techcrunch.com/2018/01/18/the-becdot-is-a-toy-that-h...
|
| https://techcrunch.com/2022/03/10/dot-pad-tactile-display-ma...
|
| https://techcrunch.com/2023/03/17/the-monarch-could-be-the-n...
|
| Something I've heard is that the content, APIs, etc are equally
| important, or you end up with a great device with nothing to
| display.
| samatman wrote:
| Reading through this, it really strikes me that you're using the
| wrong printer for the job.
|
| This sort of component is a natural fit for a resin printer. The
| registration slits from #8 can be created reliably with a resin
| printer, and I'm confident you'll get better dots as well.
|
| Furthermore, the speed of printing is by Z axis for a resin
| printer, not volume of the part. So you can print as many wheels
| as the bed will fit in the same time as one, which should only be
| about ten minutes on a resin printer. Resin also has a lot more
| flexibility in its properties than fiber printing can, the
| toughest printing resins are tougher than any fiber for this
| application, so the parts would last longer.
|
| Once you have the process dialed in, you can probably print these
| in layers, which can be clipped apart and UV treated in batches,
| or maybe just use a magnetic fixture if you don't mind attending
| the machine more closely, they'll just pop off of one of those.
|
| It reads like #8 sent you off on a substantial mission because of
| printer fidelity in the registration spokes, a resin printer
| would let you explore that design more thoroughly.
| sitkack wrote:
| I think PCB based designs will have a better Design for Mass
| Manufacturability.
|
| See the work of Carl Bugeja.
|
| https://www.youtube.com/watch?v=oa6sP-joAr8
|
| Either motors, or solenoids, electromechanical brakes, compliant
| mechanisms.
| contingencies wrote:
| This is the approach I used for my prototype (thanks to Carl!)
| and it does function.
|
| However, since the area is quite "edge case" (rarely developed
| in public), there remain challenges in balancing the electrical
| and control requirements with physical requirements,
| electromagnetic density, part selection, manufacturing process
| and cost.
| kkylin wrote:
| A portable and affordable braille reader would be great. I had a
| couple of blind students in my calculus course a couple years
| ago, and screen readers are just not a good substitute (too slow
| and hard to understand when there are a mix of words and
| equations). This is especially the case in timed assessments like
| exams and quizzes, but even for homework it is a serious obstacle
| for the students.
|
| Now, if there were only a FOSS tool to compile tex into Nemeth...
| traverseda wrote:
| https://hackaday.com/2021/06/27/mechanical-7-segment-display...
|
| This is the approach I would take to this problem. It could be
| miniaturized a great deal.
|
| Notched cams seem like an obvious win here.
| contingencies wrote:
| I took a look at creating an open source solution in this area
| last year and in fact someone sent me this page last week. The
| biggest challenge is _spatial_. The braille standard places pins
| very close together.
|
| In modern commercial braille terminals, generally a large
| assembly is offset from the braille block in order to support it.
| However, this is not feasible if you want to have a dense array
| of braille blocks. The primary reason for the bulky designs is
| that they rely upon piezo-electric crystals which move only a
| small amount and thus require long levers to actuate the required
| length. Such a mechanical configuration limits you to two lines
| of text close together at a maximum.
|
| Another category of solution explored is wheel based solutions, a
| well established category which fail predominantly on density.
| Specifically, _if you cannot place two lines of text very close
| together vertically then you are going to have problems providing
| a significant amount of information at once_ , because you are
| either going to have 1-2 very long lines or lines will be so far
| apart as to create an enormous matrix with reach issues. They are
| also sub-par on mechanical complexity, aggregate weight, refresh
| speed, and assembly cost due to part count.
|
| Two alternatives are pneumatic actuation and electromagnetic
| actuation. The problem with both is that there is no standard
| solution suitable for small size / high spatial density required,
| but perhaps one may be developed.
| https://youtu.be/k1inMrAZ_Eo?t=45 is an example of an actuator
| created within a relatively small size which would be potentially
| inexpensive to deploy. Ultimately, data comes electronically so
| pneumatics may be seen as an expensive and complicated middle-
| ground offering lower weight as its primary benefit but probably
| sub-ideal as a primary focus of research due to additional cost
| and complexity.
|
| My analysis therefore concluded that the future of braille
| displays lies in on-PCB coils for micro-actuation to reduce cost,
| weight, and part count while increasing density. This approach
| was inspired by Carl Bugeja's videos. Since August 2023 I have a
| working prototype of sorts using commercially available dowel
| pins and multiple PCBs stacked in a vertical structure. The
| initial prototypes of this onboard electromagnetic coil based
| actuation system showed great promise but remain to be validated.
| Chief concerns are torque and a locking solution, the latter
| being important for reducing power consumption, though fallback
| strategies exist (eg. hand tracking or 'presence detection'). I
| am currently focused on other areas but would like to return to
| this in due course. I would be happy to open source my work (BOM,
| KiCAD, OpenSCAD, notes) if others are interested to take it
| forward.
|
| The current prototype is as follows.
| [?] [?] [?] [?] ==[?]==[?]==[?]==[?]==[?]==[?]== PCB
| 1 ==||==||==[?]==||==||==[?]== || || || || || ||
| || M || M || || || M || M || M ||
| ~ || ~ || M ==||==C==||==C==||==C== PCB 2
| ==||==C==||==C==||==C== || || || M
| || M M M M ~ M ~
| ==C=====C=====C===== PCB 3 ==C=====C=====C=====
| Position at rest. Ejected position.
|
| PCB 1 functions as a cheap precision guide for the pins.
|
| PCBs 2+3 function as coil bases for the pin actuation. Two are
| required because the required coil density cannot be achieved
| with only one PCB. (This necessarily means half the pins are
| longer and half the pins are shorter.)
|
| M is a small circular magnet, glued to the base of the pin.
|
| C is an on-pcb coil at close to maximum density. When C is
| energised, M ejects with great force, but because M's diameter is
| greater than that of the pin's PCB hole, the pin-magnet
| subassembly stops its vertical travel at the predetermined
| position.
|
| ~ is an active coil field.
|
| Benefits of the design: cheap, uses commercially available
| components, low weight, achieves required density.
|
| Challenges remaining: Energy consumption, simple cheap control
| plane to maintain density, locking mechanism (non-energised
| mechanism for maintaining raised state), manufacturing process
| development (automation required for cost-effective output due to
| large number of pins).
|
| References: http://libgen.rs/scimag/?q=braille+display
|
| Other open source attempted solutions:
|
| (1) Electrotactile display.
| https://github.com/tanjeffreyz/electrotactile-braille-displa...
| https://patch.com/california/dublin/dublin-high-student-crea...
| (Upsides: No moving parts. / Downsides: Apparent calibration
| issues. / Status: Apparently abandoned.)
|
| (2) MOLBED https://hackaday.io/project/27126-molbed-2-modular-
| low-cost-... (Upsides: Functional. / Downsides: Extremely tedious
| assembly. / Status: Apparently abandoned.)
|
| (3) Slider https://www.youtube.com/watch?v=rTzhWKBfiuk (Upsides:
| Viable alternative to piezo-electric crystals. / Downsides: Takes
| too much space on the other axis, so unsuitable for multi-line
| (page-style) braille terminals. Still substantial mechanical
| complexity. / Status: Apparently abandoned.)
|
| (4) Ultrabraille https://ultrabraille.blogspot.com/ (Upsides:
| Multiplexed multi-user concept, like Unix timesharing. /
| Downsides: Old, relies upon manually wound pin solenoids,
| apparently does not match braille standard spacing, seemingly
| never completed as a product after 5 years of research. / Status:
| Apparently abandoned.)
|
| (5) Flat pneumatic actuators
| https://www.youtube.com/watch?v=LlxUZABcah0 - shows how to make
| small collapsible pneumatic actuators from silicone and mould
| release agent using 3D printed moulds.
| mzs wrote:
| It seems something like the media produced from am embossed
| labeler or stylus could work. Dot matrix printer head could be a
| good starting point. If the medium was vinyl like it possibly
| could be reused by feeding it through warm rollers to the print
| head.
| itronitron wrote:
| I think an alternative approach would be to have some sort of
| woven fabric loop that can have raised braille dots stitched into
| it from the right side and then the loop is pulled to the left.
| So it would read like one of those scrolling LED banners except
| it would be a fabric belt with raised dots.
|
| Maybe the simplest approach mechanically would be to have Nitinol
| wires running vertically, parallel to the 'weft' thread. To print
| a single letter in Braille would require stamping two Nitinol
| wires to render the raised dots in the correct positions, and
| then feeding the fabric belt to the left. On the return side,
| hidden underneath the display, the Nitinol wires could be
| returned to their original state.
|
| Alternatively, any technique that could raise a knot in the
| fabric which could then be easily released would be worth
| pursuing. That could be as simple as something that pushes a loop
| up (for a braille dot) through the fabric belt and then pulls it
| back out on the return trip.
| mNovak wrote:
| I wonder if the tiny unipolar motor in a quartz watch would have
| enough torque to spin a small half-character wheel. Those things
| are dirt cheap, and thin, so you could realistically drive each
| cell independently.
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(page generated 2024-03-16 23:00 UTC)