New Line build log - Honeywell 101SW1-based Hall Effect keyboard

[jd29]

The 101SW1 was used in Honeywell's TDC control systems, and possibly other machines.

Pictured: "The Honeywell TDC 2000 was introduced to the North American market in 1975. The first system to use microprocessors to perform direct digital control of processes as an integrated part of the system. This distributed architecture was revolutionary in 1975 and became the new standard for process control. Digital communication between distributed controllers, workstations and other computing elements (peer to peer) was another major innovation and advantage of the DCS. Computer based process control systems before the TDC 2000 were mainly data collection and alarm systems with controlled dopneumatic loop controllers and standalone electronic controllers." (src)

Not as historically significant as the space cadet, but process control is of some interest to me so I was excited to find all this out 



I don't have a $_0,000 TDC lying around, so the board is useless in its current form. I want to take the switches and the mounting rails and make a new keyboard. My intentions:
* carry over the matrix layout, for better or worse
* reflect the nature of the original board in a simple, practical design
* don't spend too much money

Quick sketch and tentative layout:



Oh, and here's my board. 25 Hall Effect with LEDs and relegendables, 76 Hall Effect with PBT doubleshots. I was surprised that the ones on the left weren't cheap substitutes, but then again this keyboard retailed for about $2,000. Made by Micro Switch in Freeport, IL.



I already have the PCB blanks, so I'm hoping to have that finished soon (still figuring out PCB design). I'll put an ATMEGA32U2 under one of the black stabilizer switches.

[jd29]

Guess I'll reserve the first post.

[piemancoder]

This is very cool! What do the switches feel like?

[jd29]

This is very cool! What do the switches feel like?

Thanks! They're linear and very smooth. I think the actuation force is about 65g. It's hard to get a real sense of the typing feel because the key groups aren't big enough to put two hands on, so I won't really know until I have the PCB put together.

There's a thock on bottom and top out, but these switches are very quiet overall. They sound nothing like the few Hall Effect typing videos on Youtube - those old boards have huge cases for the sound to resonate in.

They're the most solid switches I've ever felt. I think the ultra-thick caps help with that. There's no conventional plate, but the switches are mounted on steel rails on top of a hard, rigid insulating layer, and then the PCB, so they feel plate-mounted.

[dorkvader]

I have always- wanted to get one of these and convert it to a useful layout. Let me know if you want any help with sensing, NKRO, etc. I have been "sorta" working on this for the last few years and really need an excuse to finish up

note: these sensors turn on ond off really fast. some kbs like the symbolics strobe the power lines to turn on one column at a time, and then sense what is pressed in the column for NKRO, as configured, these useally have 2KRO. they operate with a Schmitt trigger on the analog output of the hall sensor to make a digital output with a little hysterises that does not need debouncing. you can scan the matrix at several hundred KHZ and they operate a few orders of magnitude better than other switches from cherry alps or IBM.

[piemancoder]

This is very cool! What do the switches feel like?

Thanks! They're linear and very smooth. I think the actuation force is about 65g. It's hard to get a real sense of the typing feel because the key groups aren't big enough to put two hands on, so I won't really know until I have the PCB put together.

There's a thock on bottom and top out, but these switches are very quiet overall. They sound nothing like the few Hall Effect typing videos on Youtube - those old boards have huge cases for the sound to resonate in.

They're the most solid switches I've ever felt. I think the ultra-thick caps help with that. There's no conventional plate, but the switches are mounted on steel rails on top of a hard, rigid insulating layer, and then the PCB, so they feel plate-mounted.

Sounds like the perfect linear switch to me! Those caps look very nice and super high quality. Do you need the rails to actually put the switches on the PCB? And how hard are they to find?

[jd29]

I have always- wanted to get one of these and convert it to a useful layout. Let me know if you want any help with sensing, NKRO, etc. I have been "sorta" working on this for the last few years and really need an excuse to finish up

note: these sensors turn on ond off really fast. some kbs like the symbolics strobe the power lines to turn on one column at a time, and then sense what is pressed in the column for NKRO, as configured, these useally have 2KRO. they operate with a Schmitt trigger on the analog output of the hall sensor to make a digital output with a little hysterises that does not need debouncing. you can scan the matrix at several hundred KHZ and they operate a few orders of magnitude better than other switches from cherry alps or IBM.

Thank you, dorkvader! I'll desolder a few switches tomorrow to try and test out a small matrix. I'll also work on documenting those "lamp" switches.

Sounds like the perfect linear switch to me! Those caps look very nice and super high quality. Do you need the rails to actually put the switches on the PCB? And how hard are they to find?

Yep, they're said to be the smoothest linears because there's no contact mechanism. You need the rails, or some sort of accommodation to replace them.



The Hall effect IC is soldered to the PCB, but the rest of the switch assembly is totally separate, held to the board by those rails. Without the clips, they'd simply fall off. And the domes in the middle hold the springs steady. They're probably impossible to find, but I think you could easily find a place to fabricate them for you, if you somehow obtained switches with no rails.

Let me know if you need measurements, or I could send you a cut of mine for a shop to replicate. And here's another shot of those caps - they're a little more substantial than those German things everybody loves so much The texture is very nice. From what I've seen, caps like these are more or less standard for Honeywell Hall effect boards.

[dorkvader]

And here's another shot of those caps - they're a little more substantial than those German things everybody loves so much The texture is very nice. From what I've seen, caps like these are more or less standard for Honeywell Hall effect boards.

Here is a compendium I made of all the different hall effect caps I know of
https://www.flickr.com/photos/dork_vader/albums/72157662083935704

The only different ones (not pictured) are the sculpted profile (almost identical to signature plastics' SA profile) but meant for angled keystems

[pr0ximity]

And here's another shot of those caps - they're a little more substantial than those German things everybody loves so much The texture is very nice. From what I've seen, caps like these are more or less standard for Honeywell Hall effect boards.

Here is a compendium I made of all the different hall effect caps I know of
https://www.flickr.com/photos/dork_vader/albums/72157662083935704

The only different ones (not pictured) are the sculpted profile (almost identical to signature plastics' SA profile) but meant for angled keystems

Wow, those triple-shot caps are awesome!

I should have a Hall Effect board of my own coming to be shortly, will be following this thread with lots of interest. It sounds like between this project and the work going on over at DT this is a nice time to grab one of these boards!

[CPTBadAss]

I should have a Hall Effect board of my own coming to be shortly, will be following this thread with lots of interest. It sounds like between this project and the work going on over at DT this is a nice time to grab one of these boards!

What are you referring to on DT? I'm really hoping this thread or some other information will lead to having Hall Effect boards being usable over USB. I wanna usable Hall Effect board so bad

[pr0ximity]

I should have a Hall Effect board of my own coming to be shortly, will be following this thread with lots of interest. It sounds like between this project and the work going on over at DT this is a nice time to grab one of these boards!

What are you referring to on DT? I'm really hoping this thread or some other information will lead to having Hall Effect boards being usable over USB. I wanna usable Hall Effect board so bad

https://deskthority.net/workshop-f7/converting-my-wang-t12379.html

From what I understand they've been converted once or twice before. But it comes down to how easy of an interface the board has. Some are more archaic than others, being early terminal boards.

[jd29]

Sorry for the silence. I have too much other stuff to deal with, it'll be some months before this project goes anywhere.