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PC Keyboard rewiring

I am having the following problem shown in this diagram, and have a solution that I think might work - but I am not sure. Here is the diagram:

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My problem is that I am trying to build a music controller - essentially a bunch of sample triggers - and this is most cheaply done via keymappings, which the software (Ableton Live 5) supports. But, to get the keys I need, I will use almost every key and its shifted complement.

This has led to two issues:

One, I can make EITHER the shifted keys work OR the non-shifted keys, simply by activating the keyboard matrix's shift key and then wiring spst switches to the other mappings. Alternately, I can of course leave the shift key off, and wire stuff that way.

Two: The other issue is if I attach the shift leads to two switches, each switch will turn on ALL keys hooked to the switch - enabled wires

- I guess the current flows through the whole circuit, so I was thinking diodes might be the answer.

I even though about using TWO usb keyboards, and wiring one for the shifted and one for the non-shifted keys. Either way, though, I cannot permanently wire the shift key in the ON position, and so I still must solve problem #2 in any case.

I'm very new to electronics, though so this might be off base. I know there HAS to be a solution - because obviously, the keyboard has the ability to do this prior to dissassembly!

If anyone can suggest another solution - like a way to send the keys from a custom-built controller that sends the ASCII codes, or the scan codes - I'd be interested in other options as well. One other potentioal snag with my plan is that if I press a button to a shifted character and another to a non-shifted char, BOTH chars will be shifted, unless I can somehow figure a way to send the signals alternately.

If you want to see the controller concept I am building, you can see it here:

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Reply to
dengel72
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There are a number of projects that use PC keyboards, and the protocol to the computer is well documented. Do some web searches, see what you come up with.

If it were me, even though I'm pretty good with this kind of stuff, I'd be tempted to find a project that replaces a keyboard and start with that.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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Reply to
Tim Wescott

I wouldn't say "well documented." Just prolifically. I haven't seen anything on the web either as accurate or as detailed as my copy of IBM's Technical Reference series on the subject of the traditional keyboard. Even taking multiple sites together. Which is too bad because that information is important for robust use and not easily inferred through examination.

Jon

Reply to
Jonathan Kirwan

The problem is that I am new enough to electronics that I might not understand what's been written! This is totally new territory for me, and what I have learned so far has been through experimentation only.

I've certainly been searching for the info, but either I don't know what to search for or the info isn't documented. The closest I have found were people referring to "key ghosting", which gave me the diode idea.

Reply to
dengel72

People have been doing this for decades - in fact, there are boxes on the market that accept a whole bunch of contact closures and send keycodes to the PS-2 keyboard port. I don't konw if they have them in USB yet. Here's a place to start:

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Have Fun! Rich

Reply to
Rich Grise

Here's another:

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Cheers! Rich

Reply to
Rich Grise

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