Keyboard Emulator

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Sambuchi
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Keyboard Emulator

Post by Sambuchi » Mon Dec 18, 2006 5:24 am

Hello all...

I am in the process of building a Keyboard Emulator.

Something like this...


http://199.236.69.21/products/lp24.html


These boards go for $60.00 and UP!

Theres a possibility that I will need more than just one where going to a PCB house and making several would be considered.

I should be able to make an emulator... anyone attempt to make one of these or know of a good place for info?

As of right now I am going with an ATMEL for my processor... I'm on the ATMEL bandwagon for now. I plan on making a PS2 Keyboard Emulator that can take 27 buttons. That will require me to setup my buttons in a Matrix. I have no problem doing the proper coding for key-debounce and ghosting. I am also considering to use express pcb for the few boards that I need.

Well... any info is appreciated.

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dr_when
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Post by dr_when » Mon Dec 18, 2006 10:29 am

This is a pretty easy thing to do and there is a glut of information on the timing and key lookup values for a ttl clocked keyboard (PS/2). There are also many inexpensive hardware keyloggers run by cheap 8 pin PICS that do this. You should have no trouble throwing something together and using PCBexpress or any of those cheap board houses is the way to go. A number of years ago I built a remote control IR transmitter that I could plug a PC AT keyboard (XT is different) into and type commands. It worked quite well and the keyboards draw so little power I could use a nine volt battery and still get quite a few hours of use.

Bob
"Who is John Galt?"

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Externet
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Post by Externet » Mon Dec 18, 2006 2:04 pm

Hi.
I may be goofing here, but what is the difference between a keyboard emulator and a real functional keyboard guts?
Can't you use the guts of a real one and assign the rows and columns pins to your needs?
Miguel

Yerry
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Post by Yerry » Mon Dec 18, 2006 4:05 pm

that's what i did: I bought a used keyboard or a buck. opened it up, and kept onlt the circuit board and oroginal cable connection. I set up two sets of solder lugs taht I attached to each line from the circuit board's IC taht DIDN"T connect to resistors, V+, GND, clock, etc-- these werejust lines going directly from the chip to the keyboard connection.

I then fired up a word processor, and started shorting lug pairs together, a la the old "battleship" game, and made note of what appeared on the monitor.

I use the fake keyboard to input switch closures from my "Super Mousetrap" Rube Goldberg-type creation; it runs the sound part of my module via Visual Basic.

very low-tech-- simple programming, no I/O timing or ports stuff to worry about, debounced by logic (system is designed so I never have the same input value twice in a row).

Neat thing is, the cheap used keyboards work great, since the part with the wea, the keyboard matrix & switches themselves, don't get used.

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Sambuchi
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Post by Sambuchi » Tue Dec 19, 2006 4:45 am

dr_when wrote:This is a pretty easy thing to do and there is a glut of information on the timing and key lookup values for a ttl clocked keyboard (PS/2).
Thanks Bob... I am starting to find more information. I have the hardware mostly done... then comes the fun stuff.

I've seen a lot of projects too using an AT keyboard on the net...

Externet wrote: Can't you use the guts of a real one and assign the rows and columns pins to your needs?
YES Miguel! :D You can... and that is what I currently have in my setup. BUT I found some "issues" doing this... well a lot!

My problems occurred when three or more keys were pressed simultaneously causing "Ghosting/Key Blocking and Masking" You can pick your keys carefully and avoid the problem... but this will start eliminating some buttons.

Then there was lack of shift key support...

Wiring wasn't a problem... but more of a pain. :x

My setup for now has 30 or so buttons and it works good with a keyboard hack but I would like to have more buttons... this would call for a different design.

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MrAl
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Post by MrAl » Tue Dec 19, 2006 5:30 am

Hi,

This sounds interesting, perhaps post some links you guys have
found?

My goal i guess would be to install a uP inside a store bought keyboard
and have it read the key depressions and store them, then allow you
to assign them to a small keyboard you attach to the big keyboard.
Even if i had 10 extra keys (buttons) that would activate several
keys in a timed order that would be good enough i bet.
The small momentary pushbutton switches are pretty cheap, so
you could make a whole bunch of programmable buttons if you
wanted to.

The uP would have to be able to:
1. Read the key closures and store them
2. Make key closures itself according to what is stored
3. Read the extra small keyboard (say 10 keys)

Is there some easy way to get it to do 1 and 2 (3 is simple)?
How would it detect a key closure for example, as most keyboards
dont use real switches.
LEDs vs Bulbs, LEDs are winning.

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Sambuchi
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Post by Sambuchi » Wed Dec 20, 2006 8:31 am

Hey Al


A lot of people do this to make a arcade games... check out this site. Go to Keyboard Encoders

On this site you can find software to map out keys... schematics and much more...

http://arcadecontrols.com/arcade.htm


On that same page... you will find link to this page, buttonbox!

http://www.leien.info/buttonbox/

GREAT SITE!

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