Simple Tactile Drawing Pad Is Quite Impressive

Everyone needs to be able to communicate and express themselves, even people with blindness or low vision. Embossing paper with some kind of stylus is a popular, low-tech option, but there’s one big problem: pressing paper from the top leaves a dent, and so letters have to either be written backwards or else felt-read backwards. For this year’s Hackaday Prize, [Subir Bhaduri] is working on a fantastic tool that embosses positively, and from the top side of the paper.

Positive emboss marks from a clever pantograph and a pair of stylii.Here’s how it works: a pointed stylus pushes upward from the underside and meets up with a concave receiver on the top side through the paper. The two stylii move in concert thanks to the pantograph-inspired parallelogram setup, which we imagine would make it easier for someone with low vision to keep their bearings as they move around the page.

The video below shows prototype #2, which is the first one that worked. Well, it works, but [Subir] says it needs improvement, so prototype #3 is in the sketching stage now. [Subir] is planning to fix the paper in place somehow and also figure out how to keep the pantograph arms out of the user’s way.

Pantographs are used for all sorts of things, but the sweetest use we’ve seen was to carve messages into chocolate hearts.

4 thoughts on “Simple Tactile Drawing Pad Is Quite Impressive

  1. Interesting, don’t know anybody with similar problems to know if it would really be helpful to them, but it sounds like a good idea.

    I wonder if perhaps the user experience would be better if they moved and pushed against a bit of leather/foam and the arm mechanism translated that movement to working beside them on the paper – so they can feel to their left/right the paper they have marked and positions of existing marking vs tool head but when moving their ‘pen’ don’t have to deal with the shifting paper and the under the page arm in quite the same fashion – just that one linkage above the leather pad to drive the mechanism and no shifting paper as that can be firmly held without getting in the users way..

    Not sure if my idea really works as well – perhaps a bit complex getting the pressure actuation to work that way, but it would get the working part of the tool out of users way – idea somewhat inspired by a drawing scaling tool the “Sketch-A-Graph Mk2” I inherited from my grandfather – very good fun, and works quite well to trace at multiple scale factors (by changing lengths of the lever arms) – but in this case instead of making the tracing tip follow the line you want to scale you are turning that tip into the effector to emboss the paper the way you move the pen.

  2. What a marvellously ingenious device, I think it really has potential. Just sort out the paper holding (perhaps consider one of those wide clips from a clipboard, maybe two) and also try free-running shoulder and elbow bearings, say small ballraces, to reduce the positioning effort. A taller stylus would make it easier to grip.

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