Some questions about Micro Switch SW series (or Honeywell dual magnet)

Hi guys. I'm really curious about the SW series and I really want to get a board with them (by my own, I can't pay a USA shipping right now). Looks like the switches come in some IBM 3277 keyboards and something called Decision Data 8010. My questions are these:
Is there any other suply of this specific series beside this two boards?
Is the huge metal plate removable without damaging it?
Looks like the hall effect sensors have a built in analog to digital converter, making this much more easy. My idea is take off the switch holder (if is possible) and sensors and then make a whole new pcb with a simple controller.
No protocol and no analog sensing = no big troubles
My beamer will feel so lonely on my desk if my xwhatsit arrives and I don't find a friend for him :lol:

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PlacaFromHell
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Unread post07 Mar 2018, 08:23

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PlacaFromHell wrote:Hi guys. I'm really curious about the SW series and I really want to get a board with them (by my own, I can't pay a USA shipping right now). Looks like the switches come in some IBM 3277 keyboards and something called Decision Data 8010. My questions are these:

Is there any other suply of this specific series beside this two boards?

Sometimes you can find just the keyboard assembly on ebay. I know of an Intel MDS keyboard and some Texas instruments silent. Also some Burroughs Terminals. Probably more that I cant remember right now.
PlacaFromHell wrote:Is the huge metal plate removable without damaging it?

What metal plate? There should be only the PCB and the cage for the switches.

Stay away from those with a rubber layer between switch and key caps, the keycaps can not be mounted on the switches without the rubber layer (see this album by haata)
Image
PlacaFromHell wrote:Looks like the hall effect sensors have a built in analog to digital converter, making this much more easy. My idea is take off the switch holder (if is possible) and sensors and then make a whole new pcb with a simple controller.

There is no real documentation on how these switches behave when they are powered on and off timing wise, at least none that I know of.
PlacaFromHell wrote:No protocol and no analog sensing = no big troubles
My beamer will feel so lonely on my desk if my xwhatsit arrives and I don't find a friend for him :lol:

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The "typing on a converted Hall Effect keyboard" club is pretty empty right now. I would be very happy to welcome you here :mrgreen:
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Unread post07 Mar 2018, 18:03

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Sometimes you can find just the keyboard assembly on ebay. I know of an Intel MDS keyboard and some Texas instruments silent. Also some Burroughs Terminals. Probably more that I cant remember right now.

I think you are confused the TI Silent should use SD series.

What metal plate? There should be only the PCB and the cage for the switches.

This one Image

There is no real documentation on how these switches behave when they are powered on and off timing wise, at least none that I know of.

I asked some time ago about that and a guy told me that they have a built in analog to digital converter. Anyway nothing that a bunch of diodes can't fix. Is just get a 0 - 1 variable with a reasonable delay, is much more easy than work with capacitive switches which have a constant AC no matter if the key is pressed or not.

The "typing on a converted Hall Effect keyboard" club is pretty empty right now. I would be very happy to welcome you here :mrgreen:

I would love yo join :D
Last edited by PlacaFromHell on 07 Mar 2018, 18:50, edited 1 time in total.
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Unread post07 Mar 2018, 18:22

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PlacaFromHell wrote:
Sometimes you can find just the keyboard assembly on ebay. I know of an Intel MDS keyboard and some Texas instruments silent. Also some Burroughs Terminals. Probably more that I cant remember right now.

I think you are confused the TI Silent should use SD series.

They were produced over a range of years. Some of the the oldest used SW. Later they switched to SD. Some even use HiTek modular switches.
PlacaFromHell wrote:
What metal plate? There should be only the PCB and the cage for the switches.

This one Image


Image does not load. If you are talking about this: ...

Image

... that is what I called the cage above. I just checked two of my board and, like in the picture above, there are small rivets that hold the PCB and the cage construction together:

Micro_Switch_SW_rivets.JPG
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Unread post07 Mar 2018, 18:41

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Thanks man! This helps a loot.
Maybe the rivets can be replaced with very small bolts (I have some switch modules that are screwed to the pcb with the most thin bolts I've ever seen)
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(M122 LED overlay)
Are the hall effect sensors directly soldered on the PCB? This starts to be promising
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Unread post07 Mar 2018, 19:08

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PlacaFromHell wrote:Are the hall effect sensors directly soldered on the PCB? This starts to be promising

They are soldered to the PCB. You will have to remove the sensor and the rivets to separate PCB and cage construction.
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Unread post07 Mar 2018, 19:37

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