Can you tell me some info about this keyboard?

Slom · 26 Jun 2018, 13:51

green-squid wrote: ↑Hey dood! Great find! There haven't been many attempts, but someone has successfully converted a Micro switch numpad on geekhack once: https://geekhack.org/index.php?topic=89262.0

Someone has successfully converted a full keyboard on DT once

petrdolezal · 26 Jun 2018, 14:11

Slom wrote: ↑
petrdolezal wrote: ↑So these switches have two pins to power them and two output signal pins, so one output pin has to be 0V and the other is what? I mean is the output signal analog or digital? If it was digital, then the second output pin would just send the input voltage when a key is pressed, but if it is analog, than the voltage would be dependent on the way you pressed the key, it would be like a potentiometer. I do not know what to search on the internet, I found no info on this.
if you tell me whats is written on the retention tab on the right side of the switch in this picture, I might be able to tell you more about the pins.

That would be awesome, but we will have to wait, because I can not read the text from this photo, when I have the keyboard in my hands, I could give you more info.

PlacaFromHell · 26 Jun 2018, 17:36

Hey man. Amazing find, specially for your first one. If you are interested I made a thread with an idea to use similar switches.
workshop-f7/an-idea-to-convert-hall-eff ... 18457.html
As far as I know some switches uses one pulse to regist "press" and a second pulse to regist "relase". Others just work like normal switches but without using a normal matrix, they send an ouput to two pins. Because of this much hall effect keyboards have 1KRO.
If is the same as with SW switches, you need to do something like that for the first case:

(I don't remember who sends current here, sorry if column and row are swapped)
In the second case just remove the flip flop.
The problem here is the power supply. Very impractical I must say, but if I had a hall effect keyboard I would try to do it without a doubt. You will need a external supply.
Good luck! Don't let them discourage you!
PS: they have two output pins just to be more reliable, they do exactly the same.

petrdolezal · 26 Jun 2018, 18:18

PlacaFromHell wrote: ↑Hey man. Amazing find, specially for your first one. If you are interested I made a thread with an idea to use similar switches.
workshop-f7/an-idea-to-convert-hall-eff ... 18457.html
As far as I know some switches uses one pulse to regist "press" and a second pulse to regist "relase". Others just work like normal switches but without using a normal matrix, they send an ouput to two pins. Because of this much hall effect keyboards have 1KRO.
If is the same as with SW switches, you need to do something like that for the first case:
(I don't remember who sends current here, sorry if column and row are swapped)
In the second case just remove the flip flop.
The problem here is the power supply. Very impractical I must say, but if I had a hall effect keyboard I would try to do it without a doubt. You will need a external supply.
Good luck! Don't let them discourage you!
PS: they have two output pins just to be more reliable, they do exactly the same.

Oh wow thats so cool, you helped a lot, I think I could convert it to a normal style keyboard from this hall effect style quite easilly. My hobby is electronics, I am currently workning on a very speccial dual output regulated high voltage power supply, so I think I could handle this problem easilly, We will see

I would definitely want to try it at least.

PlacaFromHell · 26 Jun 2018, 19:57

I would feel so happy if this thing works, please document it if you can.

petrdolezal · 26 Jun 2018, 20:33

PlacaFromHell wrote: ↑I would feel so happy if this thing works, please document it if you can.

100% I will do that

petrdolezal · 11 Jul 2018, 23:24

So I have some update for you people, I will meet with the man I am getting that keyboard from, I am going to get some more things from him, some vacuum tubes, televisions and other electronic things and I am going to exchange all of this for some of my own stuff, I am going to give him sn oscilloscope and some vacuum tubes and so I will get that keyboard practicaly for free. So thats cool, he is a good man, I can not wait. And sorry for not making any updates for a while, I was ill. If you want I can show you some pictures of the things we are changing, it is not keyboard related, so I want post it here, only if you are interested in in and you ask for it. So yeah.

PlacaFromHell · 12 Jul 2018, 00:16

Yeah, sure. We love all kind of old stuff. Feel free to post anything of your interest, also we have an off topic section if you want to make a more extensive post.

petrdolezal · 20 Oct 2018, 10:01

So I have the keyboard, I will post more pictures

PlacaFromHell · 20 Oct 2018, 10:15

This thing looks so cool! Hope you can convert it.

Slom · 20 Oct 2018, 17:10

So the switches are 4B3S, these are so called "scan modules" , congrats. These support a "normal" matrix with n-key rollover. Depending on the pcb, you might have hit gold with this one.

The pins of the switches are VCC, OUT, IN, GND

Put IN low to enable the switch. If the switch is enabled, OUT will go low when the switch is pressed. You might need pullups on OUT.

You dont need any diodes

And the switches need no debouncing

Here are the two conversions with this switch type that I know of.
workshop-f7/man-vs-microswitch-converti ... 19688.html
workshop-f7/converting-a-ti-silent-keyb ... 18283.html

Cattus_D · 20 Oct 2018, 22:57

What a great board! I hope that you'll succeed at converting it!

alordi · 24 Oct 2018, 00:05

Oh!
This is definitely Hungarian Videoton keyboard.
It was connected to terminal (VDN-52500, VDX-52600) or VT-16 PC.

I have almost the same keyboards from VDX-52600 but with RAFI switches and Russian key caps. The case is the same, board and layout are very close.

VDN-52500 uses the same switches but has another board, layout and case.
I didn’t see real VT-16, but it was based on VDN terminal and must have PC layout.

I will be very appreciate if you can read the keyboard’s ROM and send the file to me!