IBM Model M BT-USB controller conversion kits

mind_prepared

21 Jul 2019, 22:32

it's been a while since I bumped this thread the last time, just letting you guys know, this project is still alive and well. Get at me if you're interested. Cheers, mp

elecsys

31 Jul 2019, 22:48

Hello Jörn!

I have a question about the Bluetooth-USB bridge.
Would it be possible to use your BT-USB bridge with an additional 'USB to PS/2' Adapter (when using the bridge as a stand-alone BT host)?

I also have a feature request, if you would consider it.
I'm looking for something in the vein of the Logitech MK850, i.e. a keyboard that allows me to switch between multiple devices (by utilizing multiple BT-USB bridges) at the push of a button.
Could you implement such a functionality?

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Redmaus
Gotta start somewhere

01 Aug 2019, 01:46

Will this work with an SSK?

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swampangel

01 Aug 2019, 02:58

Redmaus wrote:
01 Aug 2019, 01:46
Will this work with an SSK?
Yes, works great in mine :)

mind_prepared

02 Aug 2019, 22:02

elecsys wrote:
31 Jul 2019, 22:48

I have a question about the Bluetooth-USB bridge.
Would it be possible to use your BT-USB bridge with an additional 'USB to PS/2' Adapter (when using the bridge as a stand-alone BT host)?

I also have a feature request, if you would consider it.
I'm looking for something in the vein of the Logitech MK850, i.e. a keyboard that allows me to switch between multiple devices (by utilizing multiple BT-USB bridges) at the push of a button.
Could you implement such a functionality?
Hm, not sure if I fully understand what you would like to do. I've got a hunch that my choice of words, i.e. the term 'BT-USB bridge', is misleading. A real 'BT-USB bridge' would have to work both ways, but this device only works one way, solely as a BT host device. There is no client mode. You can pair a BT keyboard and mouse to the dongle and it will forward data to its USB interface, that's all it can do. I don't have access to the firmware, all I can do is tweak the user-configurable settings.

I reckon what you want to do is connect the keyboard to the USB-PS/2 converter and then use a USB male-to-female adapter to connect the dongle to the converter, right? You said 'when using the bridge as a stand-alont BT host', but I don't see yet how that would make sense since you would want to get data out of the keyboard, not into the keyboard. I also don't see where you would want to supply power to the keyboard that way. Not what you meant? Sorry, I'm lost. Can you be more specific as to what exactly you would like to do?

As far as your feature request is concerned, I assume you mean the controller, not the dongle, right? Yes, that's totally possible. But the same result can already be achieved by merely disabling the BT adapter on the host you're currently connected to and enabling the BT adapter on the next device you want the onboard BT module to connect to. The module will always connect to the first discoverable host in its proximity automatically. Unless you're frequently switching from one host to another that shouldn't be a major inconvenience. Not so? Explain.

Cheers

elecsys

03 Aug 2019, 21:31

Sorry, severe misconceptions on my part. I'll make my question more specific:

I would like to use the Model M wirelessly with an old DOS PC that offers only the PS/2 port & protocol for connecting the keyboard, and I was wondering about whether I could make this work by using the BT-USB dongle with a (passive) USB to PS/2 adapter.
Image
I guess my question should really be, if the PS/2 protocol is even supported? The port has 5V power output, and connected devices can draw 275 mA current according to wiki.



As for the feature request:
mind_prepared wrote:
02 Aug 2019, 22:02
the same result can already be achieved by merely disabling the BT adapter on the host you're currently connected to and enabling the BT adapter on the next device you want the onboard BT module to connect to.
Is there a solution that doesn't require me to fumble around in the OS though? I'm running at least two systems simulaneously, switching between them frequently, so I would require something a bit more seamless, if possible.
That's why I mentioned the Logitech MK850 - i.e. akin to just hitting a key or key combination, to switch between different systems/channels/hosts.
Image

User avatar
Polecat

03 Aug 2019, 22:04

elecsys wrote:
03 Aug 2019, 21:31
Sorry, severe misconceptions on my part. I'll make my question more specific:

I would like to use the Model M wirelessly with an old DOS PC that offers only the PS/2 port & protocol for connecting the keyboard, and I was wondering about whether I could make this work by using the BT-USB dongle with a (passive) USB to PS/2 adapter.

I guess my question should really be, if the PS/2 protocol is even supported? The port has 5V power output, and connected devices can draw 275 mA current according to wiki.



As for the feature request:
mind_prepared wrote:
02 Aug 2019, 22:02
the same result can already be achieved by merely disabling the BT adapter on the host you're currently connected to and enabling the BT adapter on the next device you want the onboard BT module to connect to.
Is there a solution that doesn't require me to fumble around in the OS though? I'm running at least two systems simulaneously, switching between them frequently, so I would require something a bit more seamless, if possible.
That's why I mentioned the Logitech MK850 - i.e. akin to just hitting a key or key combination, to switch between different systems/channels/hosts.
A passive dongle will not let you plug a USB-only keyboard or other device into a PS/2 port under any OS. Those only worked on auto-switching keyboards (and mice) that internally supported both USB and PS/2 interfaces.

USB was never supported in DOS at all. Win95B would support some early USB ports (card or onboard) with special device drivers, but it wasn't until Win98 that USB became "plug and play" with OS-provided drivers. So even if you used an active dongle (if you could find one) or a USB card it won't be supported by DOS.

elecsys

04 Aug 2019, 00:21

I figured as much, but thanks for clarifying. I'm aware about DOS & USB, which is why I asked this question in the first place, naively assuming that PS/2 support is still a thing with keyboards (since a lot of contemporary motherboards still have the port).

@Jörn
Would a version of your controller that supports both the USB & PS/2 protocol be feasible, and would you consider it for a premium?

mind_prepared

04 Aug 2019, 17:40

elecsys wrote:
04 Aug 2019, 00:21
Would a version of your controller that supports both the USB & PS/2 protocol be feasible, and would you consider it for a premium?
Well, I suppose I could do that, but I usually don't take feature requests as long as I cannot find at least 10 people that will find it useful. Spending a lot of time on implementing a feature that is only really useful to one person is out of the question (unless I'm the one person considering it useful, heh). Adding PS/2 support to the firmware would be feasible. Protocol switching would have to be done by pressing a fixed combination of keys or something like that. I do not have any unusued GPIO pins left, as a matter of fact, I've already got some pins that serve several different functions (at different times), I doubt I can add any kind of sensing feature to auto-select the proper protocol (I also have no idea how older keyboards used to do that).

I will look into toggling between known BT hosts though, shouldn't be too hard to do.

Note: I somehow started this paragraph under the assumption that you already had a BT-USB-Hybrid controller. Well, you don't, but if you had one, you could use my HIDproxy dongle as a stand-alone BT adapter. You would only need to get an active USB-to-PS/2 converter, if you can find one. I don't know how these converters are configured, i.e. what the USB interface is configured to be, but I cannot image it to be configured as anything else but a host device. It would be worth a try at least.
If you cannot find a USB to PS/2 converter (or if the price is too ridiculous to pay), you could make one out of a Teensy running somebody else's firmware that handles all the bit-banging type protocol conversion. I reckon that doesn't sound too helpful, eh?

elecsys

05 Aug 2019, 00:49

mind_prepared wrote:
04 Aug 2019, 17:40

Well, I suppose I could do that, but I usually don't take feature requests as long as I cannot find at least 10 people that will find it useful. Spending a lot of time on implementing a feature that is only really useful to one person is out of the question (unless I'm the one person considering it useful, heh). Adding PS/2 support to the firmware would be feasible. Protocol switching would have to be done by pressing a fixed combination of keys or something like that.
That would be entirely sufficient, in case you should actually commit to it.
How about a Groupbuy thread for a board with PS/2 support? Or I could ask around in a few DOS/retro forums and try to create some demand, if you're ok with that?

mind_prepared wrote:
04 Aug 2019, 17:40
If you cannot find a USB to PS/2 converter (or if the price is too ridiculous to pay), you could make one out of a Teensy running somebody else's firmware that handles all the bit-banging type protocol conversion. I reckon that doesn't sound too helpful, eh?
So far I haven't been able to find any active USB to PS/2 converters, let alone firmware for one. Only the other way around. Even if I do find one, I wonder how much input lag it would add.

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Polecat

05 Aug 2019, 01:36

elecsys wrote:
05 Aug 2019, 00:49

So far I haven't been able to find any active USB to PS/2 converters, let alone firmware for one. Only the other way around. Even if I do find one, I wonder how much input lag it would add.
You probably won't find such a converter. Besides the issue of writing a device driver that would allow USB devices to work in DOS (and one for your controller to talk to that) there would also be a serious bandwidth issue with the PS/2 port. Trying to shove the cat through the keyhole, as the old saying goes.

Back in the day before onboard USB you could buy USB cards that plugged into a PCI slot. I tried for months to get one to work on Win95b, but I finally gave up. I must have tried twenty different USB cards, which I still have here someplace. 95b's drivers wouldn't recognize any of the cards I tried, and the drivers that came with the cards only worked on Win98. So the trick would be to write a device driver for DOS that would wake up the card and another to let it talk to your controller. Not a trivial thing. But at least it wouldn't have the bandwidth issue.

mind_prepared

05 Aug 2019, 20:59

Polecat wrote:
05 Aug 2019, 01:36
You probably won't find such a converter. Besides the issue of writing a device driver that would allow USB devices to work in DOS (and one for your controller to talk to that) there would also be a serious bandwidth issue with the PS/2 port. Trying to shove the cat through the keyhole, as the old saying goes.
Well, I did find some, but I can't tell if they are still being sold today.

I believe what you say, but - as far as I can tell - this isn't what elecsys wants to do, the way I understand him. He wants to use the HIDProxy dongle as a stand-alone BT host adapter to plug into some kind of USB-to-PS/2 converter. The dongle would receive BT HID data from the keyboard controller and transmit it to the host on its USB interface. The converter board would have two interfaces, USB and PS/2, with the USB interface configured as a host device and the PS/2 interface configured as a client device (if these categories apply to PS/2, I don't know). Incoming key report data would then be converted into PS/2 format and transmitted to the host on the PS/2 interface. Obviously this doesn't necessitate any USB support on the part of the PS/2 host device. To the host, the converter will appear like a regular PS/2 keyboard.

Another thing I don't understand (well, for lack of knowledge, perhaps) is why there should be a bandwidth issue. If it works one way (as in in the case of PS/2-to-USB converters) then it will surely work the other way around as well.

mind_prepared

05 Aug 2019, 21:20

elecsys wrote:
05 Aug 2019, 00:49
That would be entirely sufficient, in case you should actually commit to it.
How about a Groupbuy thread for a board with PS/2 support? Or I could ask around in a few DOS/retro forums and try to create some demand, if you're ok with that?
Sure, why not, give it a shot. But be aware that, initially, you're probably going to need to find more like 20 or 30 people that would be interested because a bunch of them will never actually place an order and just forget about it. So by the time I've come up with something, 7 out of 10 people will have changed their mind two months ago, heh. =p
elecsys wrote:
05 Aug 2019, 00:49
So far I haven't been able to find any active USB to PS/2 converters, let alone firmware for one. Only the other way around. Even if I do find one, I wonder how much input lag it would add.
Well, most of all, BT is prone to introduce (noticeable) input lag. Some people seem content with it why other people are not. If you need super low input latency, leave BT alone. While the theoretical minimum latency of a BT connection is only 7.5ms (for Apple host adapters it's 11.25ms!), the actual latency will be much higher. What's especially annoying about BT is that the connection parameters are controlled by the host. As a developer, you can tweak connection settings all you want, a poorly configured host adapter will just override them with its own. X(

elecsys

07 Aug 2019, 21:24

Ok then, I will give it a try, and get back to you in case I find enough people.
I'd do a groupbuy thread as well, but I still lack permission for now, and I'm not entirely sure if it qualifies as one.

mind_prepared wrote:
05 Aug 2019, 21:20
While the theoretical minimum latency of a BT connection is only 7.5ms (for Apple host adapters it's 11.25ms!), the actual latency will be much higher. What's especially annoying about BT is that the connection parameters are controlled by the host. As a developer, you can tweak connection settings all you want, a poorly configured host adapter will just override them with its own. X(
Could that problem not be remedied, when the dongle enters function as a "stand-alone BT host that supplies its own BT stack", or am I misinterpreting that again?

mind_prepared

08 Aug 2019, 12:18

elecsys wrote:
07 Aug 2019, 21:24
Ok then, I will give it a try, and get back to you in case I find enough people.
I'd do a groupbuy thread as well, but I still lack permission for now, and I'm not entirely sure if it qualifies as one.
I don't think such a thread would qualify as a 'group buy' thread because there is nothing to buy yet. =p I suggest to start an 'interest thread' including a poll to probe for demand.

Make sure to explain exactly what you want the device to be able to do so that people get the basic idea. Try to avoid prompting people to think of new possible features to add, it will just confuse everybody as to what the final device is going to be able to do and what it isn't going to be able to do. =p
elecsys wrote:
07 Aug 2019, 21:24
Could that problem not be remedied, when the dongle enters function as a "stand-alone BT host that supplies its own BT stack", or am I misinterpreting that again?
Yes, since I have access to the connection parameters of the dongle, I've modified them so as to match the connection parameters of the controller's BT module. There is still some noticeable input lag though and I have yet to find out what it is caused by. The actual performance of a BT link depends on other factors as well, s.a. the type and number of other wireless radios in its proximity. I'm by no means a wifi expert, which makes it hard to figure out what to do to further decrease input latency. It's on my to-do list though.

EEE3

13 Aug 2019, 05:16

I received my conversion kit today and am thrilled with it! :D The quality is amazing, it was easy to install, and it works perfectly.

I was previously using a Hasu converter with QMK firmware and that worked fine but this kit is a whole new level of polish. It looks completely stock and of course adds Bluetooth.

It was also a pleasure working with Jörn. He really went out of his way to make sure I got exactly what I needed and would be happy with it.

mind_prepared

18 Aug 2019, 17:08

Update: Since I stopped making the PCBs myself a good while ago I suppose it's high time I uploaded some pictures of the PCBs I got from the fab house. Goodbye electroless tin plated PCBs! (pictures on first page)

mind_prepared

23 Sep 2019, 22:26

I've overhauled the firmware, communication with host app is now completely driverless. Additionally, I (finally!) made a USB HID bootloader, so performing a firmware update will be easy from now on (although the added utility may seem somewhat marginal, it's still good to have!). I've also tweaked the code a little here and there, while I was at it.

mind_prepared

01 Dec 2019, 13:01

bump, not dead (yet)

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