Search found 8 matches

by aestechnic
09 Sep 2020, 20:56
Forum: Workshop
Topic: Micro Switch sensor replacement
Replies: 4
Views: 301

Re: Micro Switch sensor replacement

Redmaus wrote:
08 Sep 2020, 18:13
[…] I didn't even know these sensors could fail […]
Yeah, I was also a bit surprised. Although Horrowitz–Hill write (in the Art of Electronics) "…we once had an epidemic of progressive magnet anemia in a Hall-effect keyboard"!
by aestechnic
02 Sep 2020, 09:25
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Re: Honeywell Micro Switch and USB interface

Here's an update with the finished project. Teensy 2.0 spying on the 8048 controller: teensy.jpg I desoldered the LED on D6. The Teensy has enough inputs anyway, but the physical location of D6 was practical. The board is powered via USB, I think it is about 4-500 mA. Strictly speaking the Teensy do...
by aestechnic
31 Aug 2020, 14:20
Forum: Workshop
Topic: Micro Switch sensor replacement
Replies: 4
Views: 301

Micro Switch sensor replacement

Hi all, I have previously reported on a USB interface for a Honeywell Micro Switch keyboard ( https://deskthority.net/viewtopic.php?f=7&t=24122 , I should update that with the finished project) and I complained about two dead keys. I managed to replace the Hall effect sensors in those with common 3-...
by aestechnic
26 Jun 2020, 17:21
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Re: Honeywell Micro Switch and USB interface

It's DSUB , it's not clear from the picture. It's the same cable You have, only a different brand. The interesting fact is that we have the part number! Mine looks a bit home made (although well made), it uses only a single wire each for GND and 5V and it does not connect through the lines correspo...
by aestechnic
26 Jun 2020, 09:31
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Re: Honeywell Micro Switch and USB interface

Luca: Hi! Yes, same board, it seems, the "CUST. PART" number matches as well. But the exterior "ti" label is different, yours is BKBD002A-003 and mine is BKBD002B-002. Whatever that means. That 3M-connector, what is it? It isn't DSUB?
by aestechnic
24 Jun 2020, 15:32
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Re: Honeywell Micro Switch and USB interface

I like this concept of "piggybacking" the existent controller, it is clever and allows to keep the keyboard as original as possible. How do you plan to power the original controller? From the USB? Does it require any weird voltages? Thanks, I was also happy with that solution. Power: yes, USB, it's...
by aestechnic
24 Jun 2020, 08:51
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Re: Honeywell Micro Switch and USB interface

That was a nice read :) Thank you. I also might need to get one of those IC-Clips, that's a cool idea to avoid modifying PCBs. I'm rather proud of teenage me, getting hold of that clip and understanding that at some point during the next 25 years or so I would probably need it! But I will eventuall...
by aestechnic
23 Jun 2020, 18:32
Forum: Workshop
Topic: Honeywell Micro Switch and USB interface
Replies: 9
Views: 1541

Honeywell Micro Switch and USB interface

Hi all, I wanted to report on a Micro Switch SD board which I'm building a USB interface for. It is an SD-16279 pcb, and the case has the label "ti BKBD002B-002". I think these keyboards were originally used with a Honeywell VIP 7200 or 7205 terminal; here is the manual: https://archive.org/details/...

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