Version 4 didn't quite work out. Printing Version 5 now.

Hello there

Version 5 of the housing is printed and it fits.
It uses the USB header I included on the PCB to get around the problem of a vertical USB plug not fitting in an expansion port slot.
I think panel mount USB ports are a standard size so people should be able to source their own one's fairly easy. I'm thinking of doing two variants. One that uses the USB port on the PCB and one that uses the panel mount break out one. People could pick which one would work for them.

I thickened up the cover itself. It fits just fine in my own case but would struggle in a case with quick releases.

Not much else to say I think.
Let me know what you think.

Ooo I like that design much better

Could probably give it a port that plugs into the din all from the i/o shield to make it work with keyboards also. Maybe even use the din for the kb and mouse? Can you run both through the same plug?

Sphere478 wrote on 2022-01-12, 22:19:

Ooo I like that design much better

Could probably give it a port that plugs into the din all from the i/o shield to make it work with keyboards also. Maybe even use the din for the kb and mouse? Can you run both through the same plug?

Hello.

At least for the moment, I can't combine the mouse -> serial and a potential keyboard -> AT into one device. The hardware of the pico can do it but the software isn't there yet.
So they would have to be two separate devices.

I don't like that either. It would take a greater mind than mine to hack tinyusb into working.

Today I've been taking a stab at making a case for external use.

This is version 2. It could do with little clips at the serial port to hold it together but other then that, I think we have a winner.

Version 3

Now with clips

I think that'll do. I got the firmware pretty much done now too. Just some debugging and maybe something small I might have missed.

Yay. I'm tired now. Time to sort out some food.

Hello there

I'm hoping to get to releasing this today.
Just some final testing and documentation.

I have a bit of a favour to ask, if you have the time would you check out the readme for this on GitHub?
https://github.com/LimeProgramming/USB-serial-mouse-adapter

Just let me know what you think or if there is anything missing/worth patching.

Thanks
-Lime

​Alright, Initial release of the firmware have been pushed to the GitHub.

Time to go for a walk.

CalamityLime wrote on 2022-01-16, 12:40:

I have a bit of a favour to ask, if you have the time would you check out the readme for this on GitHub?
https://github.com/LimeProgramming/USB-serial-mouse-adapter

Looks good! One thing I'd like to know is the cost estimate of parts/building your contraption! That will help me decide whether to pursue an overpriced OG serial rodent 🐁 or think about breaking out the soldering iron sorting the PCB and parts. Cheers!

I'm selling the PCB's I have for 20€ a pop plus postage.

I'm limiting to within the EU for the moment. I'd rather save myself the headache of dealing with export customs if I can. I'm not sure how many Europeans are here but I do have an ad up on Dosreloaded.
If there are europeans here interested, just let me know and I'll post information here.

-Lime

16ShadesOfOrange wrote on 2022-01-20, 10:26:

CalamityLime wrote on 2022-01-16, 12:40:

I have a bit of a favour to ask, if you have the time would you check out the readme for this on GitHub?
https://github.com/LimeProgramming/USB-serial-mouse-adapter

Looks good! One thing I'd like to know is the cost estimate of parts/building your contraption! That will help me decide whether to pursue an overpriced OG serial rodent 🐁 or think about breaking out the soldering iron sorting the PCB and parts. Cheers!

If you're building your own, the cost would work out to something like 10-15$ a pop. It worked out to about 12€ a pop for me when I ordered but I think the value of the euro fell so it would cost a bit more than that now.
Honestly, it's not so bad.

Hello there.

It's been a while since I've posted anything but one of the last things we were talking about here was for a similar device but for actively converting USB keyboard to old school AT keyboard.

Well, here is some bit of an update on that idea.
I looked into it every now and then since, there have been some similar projects done in the past. Namely based around a 5v avr since that makes the wiring a bit easier.

So quick highlight of some stuff I found.

• PS2DEV for arduino. Lets a 5v arduino work as a PS/2 device. Source code is available so that'll help.
• PS/2 != AT Din. Sounds silly but they work a little different. It doesn't matter for going from AT din to PS/2 but it might matter for going the other way. I read that PS2dev doesn't just work out of the box with AT keyboards. Oh well.
• Every wire has a ferrite bead inside the keyboard? I took my AT keyboard apart for the first time to have a look at her innards. Noted the values of the clamping caps and pullup resistors. But i did notice that every wire had a ferrite bead. Including the power and ground. Which was really weird since shield ground didn't have a ferrite.
• The device pulls the Clock and data lines high. I'm guessing this is so that the keyboard controller knows to init with the keyboard.
• I'm not going to have fun with the code. It looks like I will have to convert the PS2DEV lib to pico C SDK. It doesn't look fun.

Today I decided to assemble the circuit that will let me interface a Pi Pico as an AP keyboard.

This is the the circuit I ended up with what I had on hand. Not very exciting. At first I did think that all I needed was an NPN just to pull the lines low to talk to the PC, I didn't know that the PC likes to talk back to the keyboard.
So after the clamp cap and pull up resistor, the signal splits off to an AND gate (which acting as a sort of buffer, I felt like adding anything to step down the logic level voltage would mess up the signal without some kind of buffer) and to an NPN which will pull the signal to ground. I think it would benefit from a resistor on the emitter side but for the moment it's fine.

While I know bidirectional logic level converters exist which would be cleaner. I don't have have one on hand to mess around with and this circuit emulates closer to my reference AT keyboard over a logic level converter.
Plus Looking at how the timing works, I feel like a simple logic level converter risks the GPIO of the pico getting damaged.
I'm open to having my mind changed on that one.

Here's my breadboard at the moment. I'm kinda proud of the little ferrites, I got them off of a y cap of a broken electric shower. Along with a pile of switches.

So that's what I have for the moment. Feel free to comment and if you can think of a nicer circuit, let us know. If it doesn't help me, it could help someone else!
I'll tinker with this project on and off, should be something substantial then I'll make it it's own thread.

Thanks for reading
-CalamityLime

Update:

Quick one. I started porting ps2dev over to pico SDK and while testing the circuit, I realized that I would have tied one of the inputs of the and gate to high.

I tested the fixed circuit on the breadboard and it seems promising.

Another Small update.

It printed something.

My 486 machine recognises the breadboarded contraption as a keyboard and the pico prints a few letters on loop to the machine.
It's not great and I think it'll need some sort of queue system to prevent it sending lots of keystrokes at once.

Still, very promising. I didn't quite expect this to work so well right off the bat.

Thanks for reading
-Lime

that's awesome. good job!

Sphere478 wrote on 2022-03-17, 06:49:

that's awesome. good job!

Thanks!

Hello, quick notice.

I was tinkering with the USB-2-232 code and it seems like I got it working on my KVM.
Initial testing showed that the switch between my 486 and Win 10 laptop is seamless.

I'll have to do proper testing when I get a better PSU for KVM. The original 9v one shorted out and currently I'm using a 7809 and a 12v supply. It works for a few minutes before the 7809 starts to burn.

I haven't pushed out the updated code to github, it's a bit messy at the moment from tinkering.

-Lime

Good work 👍 !

I'll need to make one I have one idea that I want to try out myself and submit to you via pull request if I succeed 😀

(And because that thing is gonna be very useful)

Deksor wrote on 2022-03-18, 09:50:

Good work 👍 !

I'll need to make one I have one idea that I want to try out myself and submit to you via pull request if I succeed 😀

(And because that thing is gonna be very useful)

Glad to hear it.

I'm curious, what's the idea?

-Lime

It's simple, add the capability of switching between AT and XT, and perhaps other things that could come to my mind.