geekhack Projects > Making Stuff Together!
Dactyl Manuform and acoustics
jamster:
I would preface this by saying that keyboard case noise is never something that has occurred to me before, I am usually oblivious to it.
Has anyone ever looked into modifying the acoustics of a Dactyl, or any of the other 3D printed cases?
In the midst of printing up cases for a build, I have noticed that the nature of the case- high internal volume, hollow plastic, doesn't lend itself to the most pleasing of acoustics. The noise from switches seems to be amplified and makes it sound hollow. I am using silenced switches, which might even be emphasising case noise.
Factors that I can think of which are contributing to this:
* Lots of empty internal volume
* Material of the case
* Use of infill in the walls
* Interaction between the bottom of the case and the desk (this one is interesting, there is a marked difference in sound with the case held tight sitting on a desk with a mouse mat, and with the case held in midair)
Some things that occur to me:
Has anyone tried high infill settings? I could try 100% infill when my current print job finishes in 20 hours time But it's worth asking here in case someone else has already tried this because each case print takes forever. I've just cancelled the current print and will try 100% infill... results in a couple of days time. Not hopeful on this, rigid plastic seems an intrinsically compromised material from a sonic perspective.
I could try mass loading a printed base with Dynamat.
I doubt that foam would do anything, but maybe it's worth jamming full of foam.
One thing I suspect that would help is to totally fill the internal cavity with a potting compound. This would result in both mass loading, and removing all of the internal volume. However this would also be totally irreversible, swapping out a single failed switch would be impossible, so it seems a high risk option.
iaji:
when i was still using dactyl manuform, i used to fill it with cotton / small cut up foam. as for switch failure, you can try to use hotswap sockets like pic attached.
jamster:
That is an astoundingly neat hand wiring job you've done there.
How do those hotswap sockets work- do they completely seal off the inside/underside of the base from the top? Or are there still visible holes for the switch pins to go through? I dug through my box of random keyboard bits and found some some much simpler ones than what you are using, looks like the switch pins would stay exposed, not to mention the entire bottom of the switch itself.
Because if I did use a potting compound (presumably a 2 part epoxy as long as it doesn't destroy PLA) and there were holes, I'd end up effectively gluing the switches in via the pins anyway.
I rather suspect that the first time around, I'll have my hands full enough just with the simplest build possible anyway, hotswap might be a future consideration :)
On the other hand, I have just Googled a bit and come across the concept of shaped sound absorbers which might be worth trying- simply merging them into the case bottoms should be doable, though I imagine that there'd be a lot of trial and error tuning involved.
https://all3dp.com/3d-printed-sound-absorbers-will-bring-relief-ears/
Leslieann:
--- Quote from: jamster on Tue, 24 August 2021, 22:18:42 ---Has anyone ever looked into modifying the acoustics of a Dactyl, or any of the other 3D printed cases?
--- End quote ---
On top of a lot of 3d printing experience I tested PLA and PETG on my 65%.
PLA highest pitch (like cheap pbt caps), ABS mid, PETG lowest pitch.
More infill will deaden the sound and lower the pitch (but only so much on PLA), on my 65% I used 30% and (I think some) 50% infill PETG and it sounded pretty good.
How you print will also matter though, the smoother the inside the more higher pitch you will get reflected back at you, same with texture, a matte plastic will sound lower pitch.
Note, almost nothing sticks well to PETG, particularly glue and it will need a bit more infill since it's softer
As for hot swaps for switch failure, honestly, how often do you have switches fail? I'd be more concerned with the hot swap failing than the switch. Hot swaps are also kind of a hassle to solder.
jamster:
--- Quote from: Leslieann on Wed, 25 August 2021, 00:05:54 ---
--- Quote from: jamster on Tue, 24 August 2021, 22:18:42 ---Has anyone ever looked into modifying the acoustics of a Dactyl, or any of the other 3D printed cases?
--- End quote ---
On top of a lot of 3d printing experience I tested PLA and PETG on my 65%.
PLA highest pitch (like cheap pbt caps), ABS mid, PETG lowest pitch.
More infill will deaden the sound and lower the pitch (but only so much on PLA), on my 65% I used 30% and (I think some) 50% infill PETG and it sounded pretty good.
How you print will also matter though, the smoother the inside the more higher pitch you will get reflected back at you, same with texture, a matte plastic will sound lower pitch.
Note, almost nothing sticks well to PETG, particularly glue and it will need a bit more infill since it's softer
As for hot swaps for switch failure, honestly, how often do you have switches fail? I'd be more concerned with the hot swap failing than the switch. Hot swaps are also kind of a hassle to solder.
--- End quote ---
Thanks for that.
I'm sticking with PLA for ventilation reasons, and will try 100% infill to compare against the 25% infill cases I have sitting around.
Potting remains an option regardless, assuming I ever get this board built then it can be filled at anytime in the future- in theory it would even improve longevity if it secured my no doubt ropey soldering and wiring attempts.
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