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Which keyboard encoder?
Bgnome:
unfortunately the I-PAC4 is gonna cost at least $77 after shipping. that is a considerable amount above $40. you really have to bend your budget around this one. you have to realize that the CP is probably one of the more important aspects of the project and it is the encoder that makes the CP.
I am also planning on building a 4 player CP and have given this A LOT of thought. There are several possibilities.
as mentioned, this is the nicest solution available but it will cost about twice what you want to pay.
my original plan was to use 4 digital psx pads and a lpt1 interface i had made. it allows for 1 joystick and 10 buttons a piece which totals to 56 inputs, (same as I-PAC4). unfortunately, although being fairly cheap for me (~$20 or so total), when i tested it, it was too much of a load on my old cpu. i can barely run the games i want on my pII but this thing slowed it down too much. i can sell this setup if someone is interested..
my next attempt was to look at a keyboard hack. the one i got ended up blocking after 8 simultaneous inputs. i believe that a keyboard hack is still the absolute cheapest way to go. period.
now most people will say it is completely unworth your time and effort to attempt a keyboard hack now that very nice encoders are available for ~$30. these options basically are the keywiz, with 32 simultaneous inputs, the IPAC-VE, also with 32 simultaneous inputs, or the mini-pac, with 28 simultaneous inputs at the moment. obviously, none of these actually meets your requirement of 44, but there are ways to work with that. For example, if you do not require all 44 to have simlultaneous inputs, you can use the Shazaam function on the keywiz. you can also use the shift function on the IPAC-VE and the mini-pac. there is a way to wire it so that the shifted function only requires one button press, but remember that any of these buttons are pressed, all other buttons will be shifted also.
if the shift/shazam thing doesnt work for you, consider adding a keyboard hack along with an encoder. the mini-pac has an active passthrough for a PS/2 keyboard which you can hack for the necessary inputs. this is the path i have settled on at the moment..
i have recently found another possible option for 40+ inputs for <$40. if this ends up working, i will definitely post it..
Trimoor:
$80 is way too much for me. :(
$40 for a matrix KB encoder, but it doesn't even prevent ghosting!
Looks like its gonna be a $0.50 keyboard hack for me. :-\
I better stock up on diodes...
Bgnome:
what keyboards do you get for 50 cents and do the diodes actually improve function?
and which matrix kb encoder?
Trimoor:
I get keyboards at garage sales, good will, church sales etc...
The diodes work great. I haven't noticed a single problem on my 2 joystick + 19 button cabinet.
I was referring to the KE-18. At $40, it's the only one I considered, but it doesn't have remappable keys and doesn't avoid ghosting.
Bgnome:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=6112252696
$40.50 shipped for a custom made kb encoder with 64 simultaneous inputs! not programmable and actually comes with an AT connector instead of a ps/2 connector, but for 64 inputs, i'm not complaining..
i will post a review once i get it and wire it in..
here is the email i got from him after asking him some pertinent questions about the item:
--- Quote ---Dear
Unlike other encoders on the market, this board was designed deliberately to
be used in high end Vegas type gambling devices where there is no room for
error. This encoder does not "ghost" or miss any key stroke. I wrote the code
on the PIC processor myself and had to include a TON of special routines to
insure that things like this did not occur in order to meet Nevada Gaming
regulations. This board does NOT use a "keyboard chip" like other encoders do,
instead it has custom software written specifically for use in the gaming
environment.
Once you press a key, the encoder will send the make code (scan code) to the
PC only once. If you hold the key down, it will NOT repeat the key scan code
(typematic mode, like on a regular PC keyboard). The break code (0xF0 + the
scan code) is sent once the key is released.
Every key can be pressed at the same time without overrunning the keyboard
buffer in the PC. This is because each input sends the make code once as
opposed to regular keyboard encoders which send the data for each key over and
over
until it overflows the keyboard buffer. The order for which the key data is
sent is dependent upon which key is pressed first, and is prioritized
accordingly (this was one of the major requirements of the Nevada Gaming
Commission).
The priority encoder section of the software will always select keys on CN1
first since in the original application this was designated as the
COIN/BILL/CREDIT/HOPPER input connector.
All other switch inputs have equal scan timing and are encoded in the order
in which they are closed.
On regular PC keyboards, if you press a key and hold it down, then press
another key, the PC will automatically switch from the first key pressed to the
next key pressed. This is a "typewriter effect" and was intended to improve
typing skills on the keyboard. This encoder does not do this and will allow as
many key entries one after the other as needed. For example, if you move the
joystick to the right then press the FIRE button, the encoder will not "cancel"
the right move and only go with the FIRE button (you can try this on a
regular PC keyboard to see this effect).
Some of the encoders on the market are made using the "wedge" technique.
This technique "wedges" key codes into the keyboard communications lines without
actually interpreting the data on the data and clock lines. This technique
requires the use of a regular keyboard along with the encoder since the encoder
does not have a command interpreter. The 64-key encoder is NOT a wedge device
and does contain all the keyboard command interpreters. This will allow you
to boot your PC with only the encoder connected without getting "hung up" at
"keyboard not found" errors. The encoder will also respond to all of the PC's
"wait" commands, which are transparent to the user, but are necessary to
prevent untimely data to be sent to the PC from the keyboard and prevent
misinterpreted keystrokes or buffer overflow.
This encoder is not a matrix-driven device. It has 64 individual inputs
(single line to GROUND). No special "matrix" wiring required. Since it does
not
use a commercial keyboard encoder chip, issues such as blocking and ghosting
have been seriously addressed (as mentioned earlier) due to the absolute
professional original application for the board.
I have 74 of these boards in my stock. There were about 40,000 of these sold
to various manufacturers OEM in the gaming industry. This board was
designed, built and sold long before MAME, and now it's a rare find to get hold
of one
of these. I still design such devices, but only for OEM manufacturers (not
for MAME users).
Spike Tsasmali,
Lupine Systems
http://www.lupinesystems.com
WolfmanSpike on Ebay
It's a WOLF Thing!
Return-Path: <******************>
Date: Sun, 1 Aug 2004 20:29:02 -0700
From: ******************
Reply-To: ********************
To: ******************
Subject: Question for item #6111001313 - 64-KEY KEYBOARD ENCODER FOR MAME
PROJECTS
X-eBay-MailTracker: 10023.347.0.1
Dear wolfmanspike,
I noticed that you mentioned that one could use this encoder for MAME. Sine
I am unfamiliar with it and cannot fond much info about it, I have a couple
questions.
I understand some encoders still have ghosting/blocking issues like normal
keyboards. Does this encoder operate by scanning a matrix and would it exhibit
such problems? When you say the buffer can handle all the keys simultaneously
but the keystroke is only sent once, does the computer still register each
and all individual keystrokes at the same time? Basically I would like to know
if one could press and hold all 64 keys at the same time and still have them
all register with the computer.
Also, you said no extra keyboard is required. I only have a simple
understanding of how these things work so is it safe to assume that this will be
recognized as a normal keyboard in any computer that is ps/2 compatible, (with
the
AT>PS/2 adapter I presume)?
Thank you for your time and understanding.
--- End quote ---