[HN Gopher] Show HN: I built a custom USB Trackball
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Show HN: I built a custom USB Trackball
Author : xythobuz
Score : 68 points
Date : 2023-02-17 10:42 UTC (1 days ago)
(HTM) web link (www.xythobuz.de)
(TXT) w3m dump (www.xythobuz.de)
| floren wrote:
| Well done, shame about the ergo problems! Hopefully with some
| iteration, it could be more comfortable. My recommendation: don't
| be afraid to take up more desk space :) I'd try something which
| put the button caps in an upward-facing orientation instead of
| facing out.
|
| When I built my mouse (https://jfloren.net/bellwether.html) I
| found that in the _past_ there were these neat modules which
| packaged a sensor and a microcontroller on 1 chip, and you
| basically just had to wire it up to USB -- but those don 't seem
| to exist any more! So I picked essentially the same Pixart sensor
| as you, used the same leaked datasheets, and built my own. I _do_
| wonder why the all-in-one devices disappeared, though.
| fragmede wrote:
| Is a micro with a PLC (or just a fast enough adc+CPU these
| days) connected to a photodiode fast enough to do it in
| software?
|
| Actually it seems modern devices use a CCD and then process the
| image.
| convolvatron wrote:
| i think you'd have a hard time determining the direction from
| just one sample
| metadat wrote:
| Server is currently hugged to death and timing out for me.
|
| In the meantime, enjoy the sweet nectar of an archive.org
| snapshot link (collected yesterday):
|
| https://web.archive.org/web/20230217104641/https://www.xytho...
| gyf304 wrote:
| Something about the use billiard balls immensely amuses me. I'm
| impressed.
| freitzkriesler2 wrote:
| .de
|
| Why am I not surprised? I love Germany .
| mkl wrote:
| I would like to make custom trackballs, and pool balls are a
| great idea. I would want a scroll ring like my Kensington Expert
| mice (https://duckduckgo.com/?q=kensington+expert+mouse&t=fpas&ia
| x...). Any idea how to make such a thing?
| duskwuff wrote:
| Optical quadrature encoder, much like how mechanical mice
| worked. Make the ring with a series of evenly spaced holes on
| the inside, then use a pair of optical sensors across that
| track of holes to detect when it's moving and in what
| direction.
| mkl wrote:
| Looks like you're right:
| https://softsolder.com/2013/03/18/kensington-expert-mouse-
| tr....
|
| Using another mouse movement sensor and ignoring one
| dimension might be simpler for DIY.
|
| I don't understand how to get the stepped motion of the
| Kensington scroll rings and most mouse wheels. Maybe it has
| bumps to move past.
| duskwuff wrote:
| Hah, I'd never looked inside one before but that's exactly
| how I'd imagined it would work.
|
| The optics for a quadrature encoder are very forgiving --
| it's much easier to implement than the camera-based sensor
| that's used for position, which requires a plastic lens.
|
| > I don't understand how to get the stepped motion of the
| Kensington scroll rings and most mouse wheels. Maybe it has
| bumps to move past.
|
| Most mouse wheels use a mechanical rotary encoder, and the
| detents are inherent to that part. Some of the fancier ones
| use custom mechanisms.
| ocimbote wrote:
| Overall, I'm impressed. Very much.
|
| Now, I'd love to see a picture of how a hand is supposed to sit
| above or around this trackball because I can't picture how
| fingers can comfortably reach the 4 buttons just by looking at
| their location on the device.
|
| Which leads me to the personal opinion: I think I prefer the
| design of the testbed over the final iteration. Buttons are
| missing, I know, but... Here I stand nonetheless.
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