Main > Main Forum
Keyboard Emulator
slinger:
Don't know if radio shack has that stuff or not, I stay away from that place! Waaaaay too expensive, find an electronics store in your area or go to www.mgchemicals.com
Hi-z mean high impedence meaning not an input nor an output, almost like floating with a high resistance.
all you need to do is send the hex byte "0xFF"(255) through the serial port and the chip will send the menu back
Tiger-Heli:
--- Quote ---quote author=OSCAR link=board=1;threadid=5689;start=0#38631 date=1047787785]
I remember one time someone made a handful of ButtonBox's and offered them for sale on the Buy/Sell board, but it seems they only received negative feedback for their effort. Not that this has to do anything with your post, I'm just throwing it out there, FWIW....
--- End quote ---
Not hi-jacking the thread here (I hope), but . . .
The only Buy/Sell/Trade post I could find was this one http://www.arcadecontrols.org/yabbse/index.php?board=2;action=display;threadid=1891;start=0
The "negative feedback" came b/c the guy was selling a buttonbox with Jamma connector for 100 Euro's without the designer's permission (for about $30 in electronic components.)
Not that I'm a huge buttonbox fan, but I wanted to point out that the bad press concerned the seller and his methods, and not the operation and function of the buttonbox itself.
Grasshopper:
Slinger,
The following link gives a detailed explanation of why ghosting occurs with a scanning matrix.
http://www.dribin.org/dave/keyboard/
I'm 90% certain that your board will suffer from ghosting unless diodes are used. However presumably blocking would not be a problem as that feature is deliberatly built into the software of most keyboard encoders. Fortunately ghosting is the easier of the two problems to solve.
Personally I could live with a scanning matrix if the components are cheap (I'm going to check out the PIC prices in a minute). However circuits that don't use a matrix are generally better for the following reasons:
1. Because all the switches share a common ground there is less wiring to do.
2. Non-matrix circuits can be used with optical controls.
My suggestions for desirable features are as follows:
1. Design a stripboard layout.
2. Use direct mode instead of a matrix (better still offer a choice as with the ButtonBox).
3. Use the cheapest, most easily available components possible. This is the main flaw of the Buttonbox.
4. Incorporate a keyboard pass-through. If you don't want to use up any PIC inputs then perhaps you could incorporate Stephan Hans circuit into your own.
Keep up the good work! I wish I had the knowledge to design a circuit.
Tiger-Heli:
This time, I probably will hijack the thread . . .
--- Quote from: Grasshopper on March 20, 2003, 02:41:45 pm ---Slinger,
The following link gives a detailed explanation of why ghosting occurs with a scanning matrix.
http://www.dribin.org/dave/keyboard/
I'm 90% certain that your board will suffer from ghosting unless diodes are used. However presumably blocking would not be a problem as that feature is deliberatly built into the software of most keyboard encoders. Fortunately ghosting is the easier of the two problems to solve.
--- End quote ---
I would have to agree, although I'm not sure how the hi-z stuff factors into it.
--- Quote ---Personally I could live with a scanning matrix if the components are cheap (I'm going to check out the PIC prices in a minute).
--- End quote ---
I was just on microchip's website and it looks like they provide free sample chips (up to five different kinds and up to three of each kind per month). Of course this might not last if everyone from this board orders a microcontroller sample ;)
--- Quote ---3. Use the cheapest, most easily available components possible. This is the main flaw of the Buttonbox.
--- End quote ---
I checked digi-key yesterday and they had all the Buttonbox components for about 75% of the prices shown on the buttonbox site.
--- Quote ---4. Incorporate a keyboard pass-through. If you don't want to use up any PIC inputs then perhaps you could incorporate Stephan Hans circuit into your own.
--- End quote ---
Errrm, he does - didn't you see the Key IN and Key OUT connections on the circuit board.
Now my questions for all the electronics gurus on the board (I e-mailed the ButtonBox designer, but he hasn't gotten back to me):
The Button Box with the Atmel chip provides 32 inputs, but only 27 are supported in direct mode as shown on his site. Does anyone know how to make the other five inputs work? Does anyone know if it would be possible to design an encoder like the button box, but using two Atmel chips for 64 inputs?
Ideally (really pushing my luck here) anyone know how to make a circuit using two of the PIC processors mentioned on Slinger's site for as many direct-mode inputs as possible???
Grasshopper:
--- Quote from: Tiger-Heli on March 20, 2003, 03:46:01 pm ---Errrm, he does - didn't you see the Key IN and Key OUT connections on the circuit board.
--- End quote ---
You're right! I hadn't bothered clicking on the thumbnail of the circuit board picture because Slinger's site is so slow.
With regards to the Atmel chips, they can be bought fairly cheaply here.
http://www.futurlec.com/
However I'd rather buy locally if at all possible.
Has anyone on this board had a dealings with Futurlec?
Also Tiger-Heli, can you give me digi-key's web address please.