Help with Replacing Adaptive Switches
July 19, 2022 3:28 PM Subscribe
I'm a person with a severe physical disability who relies on a very specific type of adaptive switch to access my PC and other devices. Unfortunately, the company that provided these switches no longer makes them and I'm down to my last couple replacement switches. I'm a little worried about what to do if they break, so I'm looking for help to build replacements.
The switches are called P-switches (for piezoelectric) and they are activated with very small muscle movements (basically a twitch of my thumb). The switch itself looks like this. The switch plugs into a control box (top view and front view). The control box works fine; I just need replacement switches. I can send one of my broken switches to anyone who wants to examine it.
I'm happy to pay someone for their time to help with this project. Thanks for any help that you can offer!
The switches are called P-switches (for piezoelectric) and they are activated with very small muscle movements (basically a twitch of my thumb). The switch itself looks like this. The switch plugs into a control box (top view and front view). The control box works fine; I just need replacement switches. I can send one of my broken switches to anyone who wants to examine it.
I'm happy to pay someone for their time to help with this project. Thanks for any help that you can offer!
If you don't have any luck with the green, or if you need an emergency repair, try this ?local? hackerspace: Twin Cities Maker
posted by sebastienbailard at 3:45 PM on July 19, 2022 [1 favorite]
posted by sebastienbailard at 3:45 PM on July 19, 2022 [1 favorite]
What breaks on the switches? Do you have a bunch of the broken ones?
posted by Slinga at 3:49 PM on July 19, 2022 [1 favorite]
posted by Slinga at 3:49 PM on July 19, 2022 [1 favorite]
From the photo, the sensor appears to just be a piezo disc connected to a 3.5mm mono jack plug. The discs themselves are cheap (£0.29 from my local electronics supplier) but also very robust, so it's possible that the cable has failed rather than the disc.
Going by the style of the cable and plug, I wonder if the supplier made them by modifying crystal earpieces like this one (the kind of thing you'd use if you were making a crystal radio). The earpiece has a piezo disc inside it, so if you removed the plastic shell then you'd be left with a piezo disc on the end of a cable - which is what you've got.
posted by offog at 3:50 PM on July 19, 2022 [1 favorite]
Going by the style of the cable and plug, I wonder if the supplier made them by modifying crystal earpieces like this one (the kind of thing you'd use if you were making a crystal radio). The earpiece has a piezo disc inside it, so if you removed the plastic shell then you'd be left with a piezo disc on the end of a cable - which is what you've got.
posted by offog at 3:50 PM on July 19, 2022 [1 favorite]
On failure to fully answer, here's a $9 set of a bunch of piezo discs with pre-soldered leads. Anyone at a maker space could probably attach the 3.5mm mono jack plug to these things to at least test with. I'd be happy to try and make up some prototypes, but I'm in California and the shipping time would make iteration and testing very slow.
posted by Alterscape at 3:51 PM on July 19, 2022 [2 favorites]
posted by Alterscape at 3:51 PM on July 19, 2022 [2 favorites]
I wonder if the supplier made them by modifying crystal earpieces like this one (the kind of thing you'd use if you were making a crystal radio)
I had the same thought.
For the plug, you can get a mono 1/8" cable with leads from Digikey (you seem to be in the Twin Cities, so Digikey is great -- choose the cheapest shipping and it'll show up within a couple days anyways).
It would be pretty simple to solder that (or one of your broken switches, the wire is probably fine) to a new switch, but you'd have to find a replacement switch. It's hard to tell what the business end of the switch is. It might just be a piezo disc. (I checked piezo switches on Digikey and had no luck.)
TC Maker would be good to check out.
Oh and strain relief is something to look into if you DIY. It's probably why your switches keep failing.
posted by neckro23 at 5:45 PM on July 19, 2022 [2 favorites]
I had the same thought.
For the plug, you can get a mono 1/8" cable with leads from Digikey (you seem to be in the Twin Cities, so Digikey is great -- choose the cheapest shipping and it'll show up within a couple days anyways).
It would be pretty simple to solder that (or one of your broken switches, the wire is probably fine) to a new switch, but you'd have to find a replacement switch. It's hard to tell what the business end of the switch is. It might just be a piezo disc. (I checked piezo switches on Digikey and had no luck.)
TC Maker would be good to check out.
Oh and strain relief is something to look into if you DIY. It's probably why your switches keep failing.
posted by neckro23 at 5:45 PM on July 19, 2022 [2 favorites]
As mentioned above, this looks like a piezo transducer soldered to a mono-jack. Those piezo disks are really robust, so it probably is a broken wire or solder point that could be fixed by re-soldering or replacing the wire.
Adding to what Alterscape said, if you are planning to replace the switches completely, you will probably want to do some prototyping. Not all piezo disks will output the same amount of voltage given the same input force. So making new switches will work best if you get someone to order a bunch of different disks and have you test them out. That way you can be sure they are creating the signal that your control box is looking for.
Like Alterscape, I would be happy to help you out but I live in Montreal (although closer geographically - more complex postally). If you cannot find a local solution you are welcome to memail me and we can take it from there.
posted by keeo at 6:15 PM on July 19, 2022 [2 favorites]
Adding to what Alterscape said, if you are planning to replace the switches completely, you will probably want to do some prototyping. Not all piezo disks will output the same amount of voltage given the same input force. So making new switches will work best if you get someone to order a bunch of different disks and have you test them out. That way you can be sure they are creating the signal that your control box is looking for.
Like Alterscape, I would be happy to help you out but I live in Montreal (although closer geographically - more complex postally). If you cannot find a local solution you are welcome to memail me and we can take it from there.
posted by keeo at 6:15 PM on July 19, 2022 [2 favorites]
Also came here to say that gosh, that looks like it could be a disassembled/modified crystal earpiece--the unlikely pink color (though they were more often a "bandaid flesh" tone), the twist of the cable, and the jack are practically indistinguishable. I took apart a bunch when I was a kid.
posted by pullayup at 7:19 PM on July 19, 2022 [2 favorites]
posted by pullayup at 7:19 PM on July 19, 2022 [2 favorites]
Maybe call the engineering department at the U and see if they've got a grad student who wants to make $200.
I work at a small college, and one of our enginerds happily did some soldering for me for free once, out of pity. :7)
posted by wenestvedt at 7:49 PM on July 19, 2022 [2 favorites]
I work at a small college, and one of our enginerds happily did some soldering for me for free once, out of pity. :7)
posted by wenestvedt at 7:49 PM on July 19, 2022 [2 favorites]
I run a prototyping shop in Los Angeles and have the capability to make these for you.
Please contact me and I'll be happy to do so. I can also repair your broken switches. Edit: I sent mefi mail
posted by fake at 9:20 PM on July 19, 2022 [18 favorites]
Please contact me and I'll be happy to do so. I can also repair your broken switches. Edit: I sent mefi mail
posted by fake at 9:20 PM on July 19, 2022 [18 favorites]
If you are in the US, it may be worth your time to make an appointment with your state department of assistive technology-they follow how adaptive tech morphs and changes, and may have next-generation devices that you can try out.
They tend to know what local non-profits maintain an inventory of donated items that are available for re-use.
Our other hack is to watch eBay and Craigslist or similar sites for the item, or an item available for parts.
posted by childofTethys at 2:36 PM on July 20, 2022 [1 favorite]
They tend to know what local non-profits maintain an inventory of donated items that are available for re-use.
Our other hack is to watch eBay and Craigslist or similar sites for the item, or an item available for parts.
posted by childofTethys at 2:36 PM on July 20, 2022 [1 favorite]
Contact your local MakerSpace. I bet there are people there who would love figuring it out and 3d printing etc something for you.
posted by Jacqueline at 8:56 PM on July 21, 2022
posted by Jacqueline at 8:56 PM on July 21, 2022
This thread is closed to new comments.
I suspect that you may be able to have someone fix a broken switch by re-soldering the leads to the piezo element. Do you have a makerspace locally? Seems like the sort of thing where someone with a basic soldering iron could try and fix one of the broken ones for you. If that works, they might just be repair-able in perpetuity!
posted by Alterscape at 3:44 PM on July 19, 2022 [3 favorites]