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geekhack Projects => Making Stuff Together! => Topic started by: njbair on Sun, 09 August 2015, 14:46:35

Title: Attaching wires to a Model M membrane?
Post by: njbair on Sun, 09 August 2015, 14:46:35: I'm working on a project which may require me to add wires to a Model M membrane. Has anyone ever tried this? Any pointers?

I'm leaning towards using something like wire glue (http://www.amazon.com/Sciplus-Electrically-Conductive-Soldering-Wire/dp/B000Z9H7ZW), and maybe using some scotch tape or hot glue to reinforce those connections.
Title: Re: Attaching wires to a Model M membrane?
Post by: Oobly on Mon, 10 August 2015, 05:06:34: I used copper tape with the end folded under. Can be soldered onto. Worked for my 60% Model M conversion, but I laid out my columns / rows badly. Will rewire it when I find the time. It also still doesn't have a case... But the membrane is connected nicely to the teensy using copper tape and magnet wire.
Title: Re: Attaching wires to a Model M membrane?
Post by: njbair on Mon, 10 August 2015, 08:42:09: Quote from: Oobly on Mon, 10 August 2015, 05:06:34
I used copper tape with the end folded under. Can be soldered onto. Worked for my 60% Model M conversion, but I laid out my columns / rows badly. Will rewire it when I find the time. It also still doesn't have a case... But the membrane is connected nicely to the teensy using copper tape and magnet wire.

This really intrigues me. Do you have a bulid log or any photos? My project is similar but I'm able to use the majority of the existing membrane so I'm not worried about rows/columns.

I'm not really sure what you mean when you say copper tape with the end folded under. Pics?
Title: Re: Attaching wires to a Model M membrane?
Post by: Oobly on Tue, 11 August 2015, 04:41:30: Doh! I just remembered that I replaced that (since I was worried about it not make good contact all the time) with this stuff: http://www.adafruit.com/product/1128

It has conductive adhesive so you don't need to fold the end under. Just cut to the right size, stick it on the trace on the membrane and solder your wire on.

No build log, but I think I have a photo or two somewhere. It's still an incomplete project (which may never get finished) so I didn't post anything about it.

P.S. actually found a pic on my phone, but will have to post it when I get home later.
Title: Re: Attaching wires to a Model M membrane?
Post by: njbair on Tue, 11 August 2015, 08:56:29: Quote from: Oobly on Tue, 11 August 2015, 04:41:30
Doh! I just remembered that I replaced that (since I was worried about it not make good contact all the time) with this stuff: http://www.adafruit.com/product/1128

It has conductive adhesive so you don't need to fold the end under. Just cut to the right size, stick it on the trace on the membrane and solder your wire on.

No build log, but I think I have a photo or two somewhere. It's still an incomplete project (which may never get finished) so I didn't post anything about it.

P.S. actually found a pic on my phone, but will have to post it when I get home later.

That looks perfect. Thanks!
Title: Re: Attaching wires to a Model M membrane?
Post by: lkong on Tue, 11 August 2015, 13:02:37: I just finished my model M restoration.
Had some problem with the membrane.
I fixed that with copper tape and conductive paint.
http://imgur.com/a/tbUD4
(http://i.imgur.com/nQFq1pW.jpg)
Title: Re: Attaching wires to a Model M membrane?
Post by: njbair on Tue, 11 August 2015, 13:16:41: Quote from: lkong on Tue, 11 August 2015, 13:02:37
I just finished my model M restoration.
Had some problem with the membrane.
I fixed that with copper tape and conductive paint.
http://imgur.com/a/tbUD4
Show Image
(http://i.imgur.com/nQFq1pW.jpg)

That looks great! I bought some adhesive copper tape and a spool of magnet wire. Going to try adding solder pads with the tape, and soldering the magnet wire to those.
Title: Re: Attaching wires to a Model M membrane?
Post by: hasu on Tue, 11 August 2015, 13:33:35: Quote from: Oobly on Tue, 11 August 2015, 04:41:30
Doh! I just remembered that I replaced that (since I was worried about it not make good contact all the time) with this stuff: http://www.adafruit.com/product/1128

I also used similar copper tape with conductive adhisive but it didn't work for me without "needling". I had to stab with knife to get it connected electrically.

I remember 3M embossed copper tape worked well without the "needling".
http://www.digikey.com/catalog/en/partgroup/1245/12570

This pic shows "needled" tapes.
(http://i.imgur.com/VIifth.jpg)
https://geekhack.org/index.php?topic=29483.0
Title: Re: Attaching wires to a Model M membrane?
Post by: njbair on Tue, 11 August 2015, 13:54:36: Quote from: hasu on Tue, 11 August 2015, 13:33:35
Quote from: Oobly on Tue, 11 August 2015, 04:41:30
Doh! I just remembered that I replaced that (since I was worried about it not make good contact all the time) with this stuff: http://www.adafruit.com/product/1128

I also used similar copper tape with conductive adhisive but it didn't work for me without "needling". I had to stab with knife to get it connected electrically.

I remember 3M embossed copper tape worked well without the "needling".
http://www.digikey.com/catalog/en/partgroup/1245/12570

This pic shows "needled" tapes.
Show Image
(http://i.imgur.com/VIifth.jpg)

https://geekhack.org/index.php?topic=29483.0

I'm wondering if the conductive adhesive is conductive enough for such a low-voltage application. I do have some electric paint (http://www.bareconductive.com/shop/electric-paint-10ml/) that I can use to cover the ends of the tape, just to be sure.
Title: Re: Attaching wires to a Model M membrane?
Post by: Oobly on Fri, 14 August 2015, 05:22:37: I used the tape from Adafruit and it worked fine with a Teensy, but it may depend on what controller you're using (signal strength and sampling method).

I made sure to press it down firmly on the membrane, so it was really firmly attached and then soldered the wires on carefully.

[attach=1]
Title: Re: Attaching wires to a Model M membrane?
Post by: njbair on Fri, 14 August 2015, 13:14:49: Quote from: Oobly on Fri, 14 August 2015, 05:22:37
I used the tape from Adafruit and it worked fine with a Teensy, but it may depend on what controller you're using (signal strength and sampling method).

I made sure to press it down firmly on the membrane, so it was really firmly attached and then soldered the wires on carefully.

(Attachment Link)

I'd have to think if the 5V Teensy works, then the stock Model M controller will work as well. But I'll do some testing to be sure.

If the stock controller won't work I'm not really sure what I'll do, since the membrane has 29 pins which is way too much for the Teensy...