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AT to XT Keyboard Converter

I'm game for a bare chip, Chuck; I'll be in touch off-list - hope it works better than the last time ;-)

BTW, just had a closer look at those special keyboards; turns out they have an XT/AT internal jumper so that's one less need for the XT > AT version.
 
Andrew Lynch, the great hardware guy that he is, has whipped up a schematic and PCB prototype for this project. What this means is that we could very likely kick off a PCB of these little guys and get some made up.

He's asked me to check it for accuracy, so I thought I'd come here and ask chuck(G) and others the following:

can you take a peek at:
http://www.waste.org/~winkles/AT2XTKBD-sch.pdf
and
http://www.waste.org/~winkles/AT2XTKBD-brd.pdf

and see if they look right to you?

And then the next question is, if we were to build said PCB, how many people would be interested in getting one or more? I'd rather not clutter up this thread with a bunch of "me too!"'s so please PM me. I think they'd be pretty cheap to build, being so small; I'm thinking about $10 for the PCB and parts.

I'm going to be ordering another batch of XTIDE cards in the next week or so, so I want to include this design in it too and save some costs.
 
The schematic looks fine, so I suspect that the PCB is okay as well. I'll turn the code over to SourceForge next week after I've had a chance to do another once-over for it.

But the sound of crickets chirping will probably tell you how many people are really interested in this. And how elated I am at the response... :(
 
thanks chuck!

I'll give the green light to andrew, if he hasn't seen this already.

By the PMs that I've been getting, I've already pre-sold 5 of these things, not including the 3 or 4 I might end up using myself, and we're only at 24 hours since I asked for input.

I think getting a dozen or two is certainly within reason, especially if the price ends up being less than a ten spot.

I wonder if I could even convert my PCjr keyboard with one of these, and an RJ11 adapter instead of a DIN connector?
 
Chuck(G) said:
The schematic looks fine, so I suspect that the PCB is okay as well. I'll turn the code over to SourceForge next week after I've had a chance to do another once-over for it.

But the sound of crickets chirping will probably tell you how many people are really interested in this. And how elated I am at the response... :(
Click to expand...
Umm, in addition to my post here I sent ya an email off-list as well, but didn't get a reply...

@ Hargle &c: is the ~$10.00 just for the PCB, or the whole kit & kaboodle?
 
Mike, your email never saw the light of day on my machine, sorry. PM's from VCF do make it through, though.

Maybe you're getting caught in my spam filters. Do you also sell Viagra or help people claim their Nigerian funds? :)
 
MikeS said:
@ Hargle &c: is the ~$10.00 just for the PCB, or the whole kit & kaboodle?
Click to expand...

I'm thinking the whole thing, but I've been known to underestimate things, so take that with a grain o' salt. If you make me solder the device together, it may be a bit more.

I think the device is ~3 bucks worth of components, I can't imagine a 3/4"x3/4" PCB can cost more than $7 each. Obviously bulk helps, which is why I'm trying to get a rough idea of how many people want. If we can piggyback onto another project, the cost should get even lower.
 
hargle said:
thanks chuck!

I'll give the green light to andrew, if he hasn't seen this already.

By the PMs that I've been getting, I've already pre-sold 5 of these things, not including the 3 or 4 I might end up using myself, and we're only at 24 hours since I asked for input.

I think getting a dozen or two is certainly within reason, especially if the price ends up being less than a ten spot.

I wonder if I could even convert my PCjr keyboard with one of these, and an RJ11 adapter instead of a DIN connector?
Click to expand...

Hi! Thanks! I can run the PCB through the design checks, etc. That's no problem. The issue is that this tiny PCB has lots of little connectors and my concern is flipping the connector pin outs. The pin out diagrams are easy to flip and it only takes one to screw it up. If you flip a connector you can check it out all day and still have it entirely wrong!

Also I made the DIN_5 part model from scratch from the datasheet so if anyone would please do a physical inspection of the PCB to ensure the right pins are connected to the right pins (manually follow the traces to double check my work). Check the datasheet drawing to ensure the holes line up and are the right diameter, etc. The DIN_5 connector is only available from Digikey with a specific part number. I can send you the datasheet or just search for DIN 5 at Digikey.

I know all this double and triple check is a PITA but I have lots of experience fscking up these things. Anything done past 2100 is inherently suspect work.

Thanks and have a nice day!

Andrew Lynch
 
Hi Andrew,

Leave them NC. The reset line is actually connected on some PCs, although the keyboard doesn't usually use it. You could also run them to some solder pads in case someone wanted to fool with them. But don't ground them!

On the other hand, some female DIN connectors have a shell contact that should be grounded. If you're not clear on that, I can take a photo and show you what I mean.
 
Hi! ARGH! I awoke from a dream last night and went to check the PCB layout. Sure enough, I had the DIN_5 connectors reversed so that the outside of the connectors were facing each other on the inside of the board not facing outward!

I will send new PCB layout tonight. I rechecked the schematic and renamed some nets so now its easier to see the connections in KiCAD. They appear to be connected properly.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-2350-ND

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-2250-ND

I will hook the shell connector pins to ground but leave the rest unconnected.

Thanks and have a nice day!

Andrew Lynch
 
lynchaj said:
Hi! ARGH! I awoke from a dream last night and went to check the PCB layout.
Click to expand...

Perhaps you should start selling Viagra via SPAM to raise some money for a vacation?

Good catch though, having them all face the right way will definatly help with functionality and overall ease of use.
 
It's nothing a little "Ye Olde Fortran" wouldn't fix.

:)

Thanks! Have a nice day!

Andrew Lynch
 
Hi! Last night I sent new files for the AT2XTKBD project to Hargle. The design checks out as best I can tell. However, I had another idea last night you may want to consider.

Do you want mounting holes? Right now its just a PCB hanging in free space. I suppose you could just wrap it in electrical tape or just leave it bare.

Its OK with me either way but some holes may make mounting this device in a little box a bit easier. Of course it would increase PCB area and drive cost somewhat. On a small PCB like this it could be a significant percentage of cost.

Also, Chuck's prototype had a LED. I don't see a lot of use for that personally but is it desired? I recall it was used for testing and is latent now.



On a tangential note, are there any other doo-dad projects like this floating about? If so there may be an opportunity in the near future. I think we may be seeing this project and even XT-IDE wrapping before too long. You may want to bring out any other ideas although that would be better discussed in a different thread.

These projects cost time and money so not every great idea will come to pass. There has to be a project lead and skilled, interested, and motivated parties (Hargle, Chuck, Per, etc) plus certain minimum amount of demand has to exist to make them viable. Not every project has those characteristics such as the N8VEM S-100 boards which barely covered themselves and are probably going nowhere.

Sorry for the topic drift. This topic should move to a different thread for more discussion if interested.

Thanks and have a nice day!

Andrew Lynch
 
lynchaj said:
Do you want mounting holes? Right now its just a PCB hanging in free space. I suppose you could just wrap it in electrical tape or just leave it bare.

Its OK with me either way but some holes may make mounting this device in a little box a bit easier. Of course it would increase PCB area and drive cost somewhat. On a small PCB like this it could be a significant percentage of cost.

Also, Chuck's prototype had a LED. I don't see a lot of use for that personally but is it desired? I recall it was used for testing and is latent now.

On a tangential note, are there any other doo-dad projects like this floating about? If so there may be an opportunity in the near future. I think we may be seeing this project and even XT-IDE wrapping before too long. You may want to bring out any other ideas although that would be better discussed in a different thread.

These projects cost time and money so not every great idea will come to pass. There has to be a project lead and skilled, interested, and motivated parties (Hargle, Chuck, Per, etc) plus certain minimum amount of demand has to exist to make them viable. Not every project has those characteristics such as the N8VEM S-100 boards which barely covered themselves and are probably going nowhere.

Sorry for the topic drift. This topic should move to a different thread for more discussion if interested.

Thanks and have a nice day!

Andrew Lynch
Click to expand...

I think mounting holes would be nice, although the PCB is small, it would be nice to put it in a box instead of having the bare PCB exposed to the elements or wrapped up in yucky tape. The LED does not seem to be needed, you should be able to determine very quickly whether the keyboard works or not.

I actually have two other projects I would like to propose that would fill very important needs.
 
I agree, a mounting hole (2, centered at each end of the board should probably do the trick) would be nice if we're going to put these in a box or something. Dumping the LED is probably a good idea; we don't need it, and it's just more parts to buy. I don't think the PC/schematic should change, I think it should just be a DNP which people could populate if they wanted to.

There's enough interest via PMs that I will order some of these when we do the next XTIDE batch, certainly before the end of the month. cool!
 
Hi! Thanks!

OK I will add the mounting holes and rev the design. I'll send you those tonight.

As for the LED, I agree but thought I'd bring it up anyway to see if there were any strong opinions either way. Some folks just can't get enough blinky lights. :)

So that's OK. Most likely anyone who would use the LED either already has a PIC 12F629 prototype board with a LED (I have one in my pile o' shtuff from an earlier project with Chuck) or can just solder one on the PCB dead bug style. All it takes is a resistor and LED soldered to one of the PIC's pins and that is not rocket science. There is no point in cluttering the PCB with useless parts for nearly the entire customer base.

Hey Chuck... do you think we could find someone interested in sponsoring a batch of those hard sector floppy pulse maker/true /READY things (whatever they are called)? I could spin out a PCB pretty easily. Basically its just another PIC circuit with a 34 header in and out, MOLEX drive power in and out. Pretty straight forward stuff.

Sorry, more tangential topic drift. Back on topic...

If anyone has other ideas for AT2XTKBD features please let me know so I can incorporate them in the next version.

Thanks and have a nice day!

Andrew Lynch
 
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