Author Topic: Re-Create the DataHand - Thumb cluster under development. Project 75% done.  (Read 248223 times)

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Offline JesusFreke

  • Posts: 55
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #800 on: Mon, 02 December 2019, 21:44:58 »
A separate thread SGTM (feel free to post a link to it in this one. otherwise I probably won't see it :).

Also, if you want to document/edit/add anything in the wiki, let me know :)

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #801 on: Tue, 03 December 2019, 03:04:52 »

Offline JesusFreke

  • Posts: 55
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #802 on: Tue, 03 December 2019, 03:23:07 »
The current design primarily uses 1/16" cube magnets. You can try to use the ones you linked, but you'll have to tweak the design to accept that size of magnet. And since they're a bit smaller, they'll be a bit weaker. In the case of the magnets for the central key, that may be a good thing, since I had to bake the 1/16" magnets to reduce their strength. In the case of the side keys, you may need to adjust the vertical alignment of the magnets between the base and the key post. In the current design, there is a slight offset between them in order to slightly reduce the key force. With the slightly weaker magnets, you may need to remove that offset to increase the key force.

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #803 on: Tue, 03 December 2019, 23:56:44 »
For larboard,

100x 1/16" N42 cube magnets - kjmagnetics
88x 1/8" x 1/8" x 1/16" N48 magnets

How did you choose the size and strength? Was it based on availability or something else?
Is it recommended to choose one small, and one larger?

I found some rounded N35 magnets, ranging from D 1mm-5mm, with thickness 1mm-5mm
I might try to get some D=2mm with 2mm thickness and D=3mm with 2mm thickness ? Do you have other recommendations?

Offline JesusFreke

  • Posts: 55
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #804 on: Wed, 04 December 2019, 00:12:09 »
A bit of both. The 1/16" ones were the smallest ones I could find that were readily available in the US, and they turned out to be about the right strength.

The larger ones are only used on the bottoms of the standoffs and the handrests, to hold them down onto the base plate, so the exact size/strength doesn't really matter. You should be able to use anything as long as you can adapt the parts to accept it and it's strong enough to keep everything stuck down onto the base plate.

Offline JesusFreke

  • Posts: 55
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #805 on: Wed, 04 December 2019, 00:24:26 »
Another thing to consider when choosing the smaller magnets is the thickness of the walls that they'll be placed in. For example, I think I chose the thickness of the key stem based on the thickness of the magnet, plus maybe 1 or 2 layer-heights worth of plastic. If you choose a thicker magnet, you may need to increase the thickness of the key stems (and also the corresponding receiving void in the base), and possibly some of the thin walls in the base too.

I tried to keep the design reasonably parametric, but there were a few things in the design that were too much of a pain to try and calculate, so I just measured or used trial and error to come up with a magic number.

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #806 on: Wed, 04 December 2019, 01:32:30 »
Thank you JesusFreke!
So, I'll need 100 magnets for the key switches, which makes more sense now.
I'll first experiment with D=2mm Thickness=2mm then.

Online ironfox

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Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #807 on: Wed, 11 December 2019, 01:30:38 »
Hey everyone,

I yet live. And have not stopped working on this, but I ran into unusual problems with some yet undiscovered solutions. After spending _quite_ some time re-modelling the main finger cluster to be a) more adjustable and b) easier to (dis)assemble, at least that part appears to be somewhat acceptable now.
Here are some modifications I believe to be improvements:
1) I eventually ditched the vertical, sliding magnet layout for the central key; it seemed to be prone for getting stuck and sometimes unrecoverably so (even via filing) and have now implemented a solution I thought impossible at first:
231642-0
By moving the magnet into a top cover plate and shaping the key itself somewhat like a hook, the magnets now pull up rather than to the side. The cover can be printed with different horizontal magnet displacements, thus greatly affecting upwards strength of this key. I have experimented with displacements up to 0.7 mm, which produces an almost ethereal key - still without getting stuck. Down to <=0.2 mm displacement the keys get rather harsh to press on the long run.
The top cover plate is held down by 2x4 1/16" magnets. All magnets are recoverable unless glued.
2) The central key is now located in a removable tube, which experiences the most frictional wear (apart from the key itself) and can be filed/replaced individually.
3) To assure cleaner sides I split the key itself into first two, later three parts, printing the central shaft horizontally to use the print sheet's perfectly flat surface. The cap part is designed around similar ideas. Since the shaft has to be pressed into the cap, that part needs to have a bottom opening, which creates an overhang if not split, which causes a ton of problems. Hence, this part is split as well. The two cap parts are actually designed to clip, which works pretty well at least when printing with a 0.25mm nozzle. Although I had the same idea to combine the cap and shaft, the best I could achieve was a sticking. Of the 8 keys I made 7 stuck just fine, one had to be glued eventually.
4) Since I introduced the top plate to handle the central key mechanic, this also increased cluster height, unfortunately. That, in turn meant the keys had to be longer, without leaning that much further than their smaller counterparts. This, in turn, meant they had to increase thickness with height, however not all to the way to the top, thus making the old way of printing very bad. I eventually split the keys into two parts each. The version I still mostly use (and which can be seen in the above schematic) requires glue. I have since developed a key part setup which should clip, but at least with a 0.4mm nozzle it's more like a sticking, requiring some initial pressure to hold. I have not used them in practice; I do not know if they hold for longer periods of time.
5) Growing tired of fiddling magnets into the holes, I eventually got the idea of making the magnet holes removable in the form of a ring-like shape. It is printed separately and can be removed and reused again in a different cluster, if necessary. The shape makes installing magnets heck of a lot easier. And, if nothing else, the magnets can be recovered easily. Since it is held by the top plate, it need not be glued or magnetized to the cluster.
6) The whole cluster is designed to fit to a PCB board, taking care of the local logic. After some mishaps and redesigns on that front, it seems to be working reliably now. There are openings for the connector and resistor network. I replaced the original 8 pin resistor network with a 6 pin one, which fits well into the width of the cluster. Out of the latest 8 clusters none have shown problems or had to be re-soldered.
Much of the above modifications are designed around reducing the risk of re-soldering anything. Once soldered, all force adjustments and replacements can be made with reprinting just one or two parts. The soldered parts remain unchanged.
7) Everything is designed in Fusion 360 now, and adjustments can be made using parameters. It's quite nifty but I think Fusion is at its limits now. I managed to produce a few freezes and crashes. Still, this is worlds apart from the software I used before.

The consequence of all the (assumed) improvements means a cluster now has heck of a lot more parts:
231644-1
And assembled:
231646-2
(I added shoes to increase traction of the metal feet).
Still fits to the original shafts and screws though. Nothing has been changed on that front (yet).

So, with that part covered, my attention moved back to the hand rest which needed some serious work. After many, many modifications and re-prints, I am currently at a four-part layout:
231648-3
Basically, the bottom part (bottom-left most, white), allows altering the inclination (along both axes) and base height of the rest without reprinting everything else. I have managed to make it adjustable via user parameters without having to fix the whole history afterwards.
The part is held by magnets, and to get to those with pliers I had to remove the central filling, which reduced traction and had to be added again with a removable inlay part (next to the right, black). When installed, it is pressed against the metal ground, ideally using a rubber surface in-between.
The center part is mostly still the same, although I keep modifying it anyways, mostly to get more space for the key clusters next to it. The top part is also continuously being adjusted to fit my hand. The main reason for all of this is that my hands are not steady, and need to be at perfect rest. Otherwise they shake and I press keys I do not want to press.
While the solution, as is, should work for most people (although with some adjustments I guess), I am currently working on some really crazy stuff to keep the fingers afloat without impairing their movement. I can adjust key strength to keep my fingers at rest but then the keys are too strong on the long run. If I make them weaker, eventually my fingers can no longer rest on them. But this, I think, is more of a personal problem most people don't have.

231650-4
I dubbed this thing 'Po's Paws'. The visual similarity wasn't actually planned :D
I think I'll just upload this stuff as is. I'm just not looking forward to documenting it properly. I'll keep you posted.
« Last Edit: Fri, 13 December 2019, 11:21:52 by ironfox »

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #808 on: Wed, 11 December 2019, 02:31:34 »
very cool! Did you use silicone wires or PVC?

Online ironfox

  • Posts: 16
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #809 on: Fri, 13 December 2019, 11:24:23 »
very cool! Did you use silicone wires or PVC?
The BOM tells me it's PVC. So, yeah, I had to wrangle them a bit. Now they stay the way I need them :)


Right, I also managed to upload the cluster STLs and some instructions how to use this.
It'll eventually, hopefully, make it into the original repo, but until that happens, here's the direct link to my fork:
https://github.com/IronFox/lalboard/tree/master/stls/ironfox%20cluster2
« Last Edit: Fri, 13 December 2019, 11:29:39 by ironfox »

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #810 on: Sat, 14 December 2019, 03:07:02 »
IronFox, which TOP (1-8) did you use? and approximately how heavy is it?

Offline ju6ju8Oo

  • Posts: 124
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #811 on: Sat, 14 December 2019, 04:02:14 »
There's a slight offset in the magnet sketch. What's the usage?

Online ironfox

  • Posts: 16
Re: Re-Create the DataHand - Thumb cluster under development. Project 75% done.
« Reply #812 on: Sat, 14 December 2019, 12:27:22 »
IronFox, which TOP (1-8) did you use? and approximately how heavy is it?

I started off using top 2, which turned out a little harsh on the long run. Some of my keys are currently 5, some 7. I will get back to evaluating how much is enough or too weak once I figured out how to keep my fingers from auto-pressing overly weak keys.
I would suggest you print one of 2, 5, and 7, and see which of those suits you best. Then maybe some in-between and eventually the whole bunch. You'll need 8 of those anyways so printing a few to test what force you need shouldn't be an issue.


There's a slight offset in the magnet sketch. What's the usage?

It's to weaken the force of the side keys. It's much larger in the original STLs, causing the keys to be much weaker. I was testing to increase their force since their length has increased. The fact it isn't exactly zero is mostly a remnant from a different layout. There is a user variable (SideMagnetDisplacement) that controls it. If you need weaker side keys, you can increase that variable, but they will not get much stronger than they are now with the current layout.
Changing the variable affects the keys only. Not the cluster.
« Last Edit: Sat, 14 December 2019, 12:30:47 by ironfox »