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Datahand Keyboard Resurrection

Discussion in 'Sensors and Actuators' started by mikeincousa, Apr 4, 2019.

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  1. JesusFreke

    JesusFreke

    10
    1
    Nov 28, 2020
    Are you using a ps/2 to USB adapter? Or plugging directly into PS/2 on the computer? I seem to recall that PS/2 isn't particularly hot-plug friendly. e.g. if the computer doesn't boot up with a PS/2 connected, it may not detect one plugged in after the fact. It's been a while since I did anything with ps/2 though, so I may be misremembering :). And it may be windows/linux specific. or even BIOS specific.

    Yeah, my guess is that it's most likely an issue with the cable to the left thumb.


    I had fully reversed engineered the circuit at one point, but I can't find my notes/schematics from that, sorry :)
     
  2. mikeincousa

    mikeincousa

    19
    0
    Sep 5, 2016
    Thanks for your quick reply.
    Yes. I am plugging into the PS/2 sockets directly. No noticeable problem with booting.
    If the pin assignments turn up please let me know.
    I will start the continuity checks on the left thumb next.
    Did you purchase the crimping tool for making a new cable that you mentioned earlier? How well did it work? Could one kluge a new connecting cable using bulk wire and crimped terminators?
    Did you have any thoughts about the toggle that came about when switching to the flat keyboard?
     
  3. JesusFreke

    JesusFreke

    10
    1
    Nov 28, 2020
    There's no kludge involved. That's just how the cable is made. I don't think I've made a cable for the datahand specifically, but I've made a lot of them for my lalboard project, which use the same "style" of connector, just in a smaller size (so even more difficult). There's a bit of a learning curve to using the crimper, but it's not too hard :). I would recommend finding a good youtube video.

    No clue about the thing with the normal keyboard. I can't think of any way that doing anything with a normal keyboard would affect how the datahand works.
     
  4. mikeincousa

    mikeincousa

    19
    0
    Sep 5, 2016
    So if just one wire in the assembly is broken I will need to replace the whole cable? No splicing in a jumper over the break?

    A bit later....Looks like I should be able to purchase a replacement cable? That could be an easier and less expensive solution. Glanced at Mouser but went not further for now.
     
    Last edited: Feb 13, 2021
  5. JesusFreke

    JesusFreke

    10
    1
    Nov 28, 2020
    Iirc, that thumb cable is a split cable, with 1 connector on the mainboard that goes out to 2 separate connectors (the thumb and LEDs). You won't be able to find a pre-made cable for that.

    I would recommend just replacing the entire cable. The crimped terminals snap into place in the connector, and aren't really meant to be removed. You can remove them, but it generally involves slightly deforming the plastic bit that holds them in place, and I find that the replacement terminal doesn't hold in place as well after that.

    If it's literally a break in the middle of a wire, yeah, you could try just splicing that wire. But I would be a bit surprised if there was a break in the middle of the wire. Anything like that would most likely be at or very near the connectors, where the most stress is.
     
  6. mikeincousa

    mikeincousa

    19
    0
    Sep 5, 2016
    I was thinking that both ends were the same. I now am recalling your earlier comment about a split cable. I need next to get it out ot the case to see what is going on. Maybe later today or tomorrow?
     
  7. mikeincousa

    mikeincousa

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    0
    Sep 5, 2016
    I have removed the blue and white cables. The caliper puller worked very nicely.
    I was not thinking about the size of wire I would need to insert for a continuity test.
    First I thought I could use sewing needles. I could not find one that would readily do the job. I have some 6-needles that may work but it would take lot of digging to find them. The closest that I could come for a fit is the end of dental pick. I have some fine pins in the sewing mix but would have to dig for them too. Likely they too would be too large in diameter

    Do you have any ideas for me? Do you know of something like a gender changer for the end? Something else I could put in female holes and get test clip on for a stable measurement?

    Maybe you have a listing of the connectors? One that would include critical dimensions?
     
    Last edited: Feb 14, 2021
  8. mikeincousa

    mikeincousa

    19
    0
    Sep 5, 2016
    I have been wracking my brains for a way to gauge a small hole in the connector. Using the blunt end of mini-twist drill seem the most feasible. It would also provide a solid connection for the continuity test.

    From Amazon:
    Precision Pin Vise Hand Drill with 25pcs Micro Twist Drill Bits Set (0.5-3.0mm) Mini Hand Drill Rotary Tool for PCB,Metal,Wood,Jewelry,Plastic,Resin Manual Making DIY Assembling Drilling
    Brand: AUTOTOOLHOME
     
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