Decision Data 8010

4_404 · 29 Jan 2021, 13:47

I just rescued what was left of a 1973 date Decision Data 8010 (serial 266). This board is in a pretty bad way, missing the case and the entire controller portion of the PCB, which has been roughly snapped off. The switches, Micro Switch dual magnet hall effect (SW series), feel fantastic though.

As I am missing the controller, my only option to run this thing is to use a new external controller. Has anyone driven SW series switches from a teensy or similar? This my first experience with Micro Switch, and I know SD switches have been converted before, but haven't seen any efforts for these switches. Thanks in advance.

John Doe · 29 Jan 2021, 14:22

Lovely, at least you have all the caps there.

4_404 · 29 Jan 2021, 14:32

All but the 'lower shift' on bottom right of the board. Unfortunately the metal cage has been bent there, and the switch and keycap are missing, leaving only the loose sensor behind.

TNT · 29 Jan 2021, 14:34

I've read from a bunch of people that they were going to handwire their own matrix (with diodes for nkro and so on). Whatever that means in detail, should be possible. Great board!

4_404 · 29 Jan 2021, 14:44

I'd love to be able to handwire or otherwise hack together some method of interfacing this with a modern computer. This would be a great board to test it on, as it's far from original condition. From looking at the work on SD switches, hall effect parts seem to be significantly more complex than anything I've dealt with before though.

John Doe · 29 Jan 2021, 15:05

here're two threads about the 4-terminal sensors working mechanism, dorkvader introduced a lot about its convertibility. I'm also in situation like what you face now, an sw board waiting to mod to usb.

viewtopic.php?p=397958
viewtopic.php?f=7&t=18163

SW series keyboards are using two of N encoding method rather than normal matrix way, that's one of the reasons why have to do some handwiring job to make it fit, like 6KRO or NKRO.

reference if you interested, sent from MMcM.
https://telcontar.net/KBK/Micro_Switch/SW#encoding

4_404 · 02 Feb 2021, 23:18

Thanks for the info. Handwiring a matrix isn't too much of an issue for me here, as the matrix is so damaged anyway due to the missing half of the PCB. This also means I have none of the original encoding hardware from the board. Unfortunately this board uses almost all pulse type sensors, which it seems no one has been able to reliably adapt yet.

I'm in the process of cleaning the board now, and I've notice that somehow part of the PCB has pulled away from the metal cage (this can be seen in the last photo in the original post). This board must have been handled extremely roughly. Sadly, this has pulled several sensors away from the PCB, either by breaking the solder joint, or snapping the leg where it meets the sensor. Hence, I've got 4 sensors (one hold type, three pulse type) which are mechanically broken, before even testing them electrically. So does anyone have any spare SW series sensors or switches from previous projects, or know where to get some? I've seen a few on ebay, but they seem to be in lots of 1, and seem to be of different types to the ones I need. See pic for reference - N56 are pulse type from 1SW17 switches, and H193 is hold type from 1SW11 switch.

4_404 · 02 Feb 2021, 23:30

I'd also like to understand how pulse type switches work properly. I've seen some info saying they give single short pulse when pressed (with no release event), and others saying that there is a pulse for press and another for release. Obviously I haven't been able to test them myself yet, but can someone who understands the switches better than I do confirm this for me?