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Converting real TI keyboard for less wires or being wireless


Tornadoboy

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  • 3 weeks later...

Thanks guys!

 

What I'm looking for is a way to connect an original TI keyboard remotely to an actual TI 99/4a, not a Raspberry Pi or PC. I've got a motherboard I built into a case so I could give it an AT power supply and build in some other mods and add on's, I made a half-ass 16 conductor cable but it's awkward and stiff, if I could reduce it down to like 4 wires or even wireless it would be a big improvement. Sure I could (and probably will) build Jedi's USB keyboard adapter and use a PC keyboard but I'd like to be able to use the original. 

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Thanks guys!
 
What I'm looking for is a way to connect an original TI keyboard remotely to an actual TI 99/4a, not a Raspberry Pi or PC. I've got a motherboard I built into a case so I could give it an AT power supply and build in some other mods and add on's, I made a half-ass 16 conductor cable but it's awkward and stiff, if I could reduce it down to like 4 wires or even wireless it would be a big improvement. Sure I could (and probably will) build Jedi's USB keyboard adapter and use a PC keyboard but I'd like to be able to use the original. 
I bounced back and forth for a while ... I landed on keeping the original innards. I actually really like the keyboard as well. So here's a thought. Use Jedimatt's USB external and Matt Epler's USB. Create a nice wooden case for the keyboard. Paint silver metallic on top. Black on bottom. Bam!

Sent from my SM-G955U using Tapatalk

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1 hour ago, Mehridian Sanders said:

I bounced back and forth for a while ... I landed on keeping the original innards. I actually really like the keyboard as well. So here's a thought. Use Jedimatt's USB external and Matt Epler's USB. Create a nice wooden case for the keyboard. Paint silver metallic on top. Black on bottom. Bam!

Sent from my SM-G955U using Tapatalk
 

I like your thinking! :D

Will that really work though? Won't the mapping be messed up as Jedi's board is expecting to convert a regular PC keyboard's output? Even if that's the case it's probably not much that would need to be tweaked in the code. 

Edited by Tornadoboy
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4 hours ago, Tornadoboy said:

I like your thinking! :D

Will that really work though? Won't the mapping be messed up as Jedi's board is expecting to convert a regular PC keyboard's output? Even if that's the case it's probably not much that would need to be tweaked in the code. 

Well, I was making the Teensy 2.0 conversion but decided that restoring the glory would be much better.  I can say that I got almost all of the keys working. A through Z, 1 through 0, Enter and Space all worked. I can send you my code IF you intend on using the Teensy 2.0, or you can get the majority of it from M. Eplers conversion (he used the Teensy 2.0++). Code will depend on the controller you use, and what wires go where. The output on the Teensy works like a USB port connected anything. As with all things, it's in the code. As the Teensy will be outputting USB Keyboard commands, the JediMatt conversion for an External keyboard "should" work. I have not researched that kind of Double Conversion. I do believe the theory to be sound, though. Heck, please prove me wrong. Either way, seems like a bit of work. 

 

My primary job is debugging and testing "It should work" components.

(Ironically JediMatt42, Matt Epler, and lil' ole me. 3 MATT'S!!!)

Edited by Mehridian Sanders
clarity
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I'm halfway there, since I now have the Bluetooth keyboard to a PC working.  Now, I need to get the Bluetooth "PC" to a Bluetooth KB working.  THen, it'll jsut be fixing up mappings.

 

My goal is exactly this, to create a remote classic KB that connects to a classic system (and optionally allows the continued use of the attached KB).  I'm using esp32 units for both sides, as the esp32 has a port of the BlueKitchen BTStack with host and dev code (sample code even).

 

And, I did the same thing with PS/2 back in the day (C64 KB to PS/2 to PS/2 to C64 KB port.  It worked fine.  So, I don't see this being an issue.

 

Just need to take a bit of time to get the BT Host code sample working.

 

TI and TANDY and 64 will be trivial (that's just matrix mappings.)

 

Jim

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On 10/16/2019 at 7:46 PM, Tornadoboy said:

I know adapters have been made to use PC USB keyboards, but has anyone come up with anything so one can use a real TI 99/4a keyboard remotely with less wires (maybe a phone cord) or just being outright wireless? 

 

You asked for a phone cord. Here's an idea for how to make such a thing:

 

Keyboard multiplexer

== 99/4A 14-pin keyboard header
8 bit input register, 8 bit output register
'165 par-in ser-out   '595 ser-in, par-out
LD,CK,Q               LD,CK,D
|||                   |||
RJ12 modular 6-conductor
|||                   |||
6 pins to:
== Arduino Pro Mini (14 ios)
6 pins to:
'595 ser-in, par-out  '165 par-in ser-out   
14 pin header
== 4A keyboard

One-way trip is 11 cycles, where cycle > 40 ns

time to do requested keyboard row on 16MHz avr: 22 cycles or 

End-to-end Update frequency is in 10 kHz or above, so it ought to be fast enough.

The signals are buffered on both ends, so they ought to travel. But check.

 

Another idea that would be a lot simpler.  Make an adaptor to 16-conductor ribbon cable with a powered buffer on each end. (add VCC and GND to power it.)

 

Put heat shrink around the ribbon cable (is this a bad idea?)

 

 

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Sometime during my high school years I removed the TI motherboard, power supply, and a speech board out of their respective cases.  I used picture hangers to hang the three parts and the flex cable on the back side of my desk.  Back then I used XB and Funnelweb for everything - those tools together were so versatile - so I never had to change cartridges.  The only part left in the console was the keyboard which I connected to the motherboard with a 4-5 foot (maybe 6'?) piece of ribbon cable (probably from one of my spare TI printer cables).  No buffer chips - maybe I was lucky?   Regardless, it was nice being able to lean back in my chair with the keyboard on my lap or move it out of the way while doing my homework.  I operated this way for a few years until I bought my first Geneve.

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23 hours ago, InsaneMultitasker said:

the keyboard which I connected to the motherboard with a 4-5 foot (maybe 6'?) piece of ribbon cable (probably from one of my spare TI printer cables).  No buffer chips - maybe I was lucky?   Regardless, it was nice being able to lean back in my chair with the keyboard on my lap or move it out of the way while doing my homework.  I operated this way for a few years until I bought my first Geneve.

I had a six foot or so cable on my keyboard too, so I could sit across the room on my couch and chat on my BBS ;) Also worked fine!

 

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