Keyboard hack: need help selecting keys

[bufalo]

Hi all,
iīve done a kb hack and after reading a couple o three tutorials I thought that I was ready, but joining a two players game I saw dissapointed that ghosting, masking and blocking where there, so my keys choice was not good (maybe for one player gaming, maybe not, but sure for two  )
This is my matrix:
http://img256.imageshack.us/i/matrizg.jpg/ sorry about the cuality, itīs a win printed screen. Hereīs the Excel .xls filehttp://depositfiles.com/files/mq4ellp76
Green keys are for Player1: 4 directions, 6 butons
Blue keys are fo player 2 and
yellows are service keys.
Is it possible to determine 20 secure keys? The six service keys may allow ghosting, masking or blocking as Iīm not going to combine them.
Thanks in advance for any suggestion

P.S: sorry, I`ve tried to put the image on my post but i canīt  

saint's edit -- attached image

[saint]

Not specifically, but you're running into the reason I don't recommend keyboard hacks anymore. A keyboard encoder without these issues can be bought starting in the $30 range. If you want the challenge of using a keyboard hack that's one thing, if you just want it to work I would buy an encoder and be done with it.

[bufalo]

Sure, even the great and extense tutorial allocated here starts telling the same, but I thought maybe I was going to learn somethig doing it the hard way and even recycle something. In fact I bought a pair of cheap usb control pads (8 buton 4 direction, 5€ each) to make a hack with them in the case the keyboard didnīt work so I would take only one to this porject and save the other for the future.
Itīs a pitty that having done all the hard work (Iīm very novice at this and it took me hours) I have to desist by failing on the last 5% but more important part of the job: the smart one.
I will keep reading suggestions and studing other matrix samples untill next weekend, then I will have time to do any change, on the key mapping or adding one usb hacked pad.
thanks saint and please, excuse my english

[Mario]

It's been a while since I did a keyboard hack, but if IIRC, in order to prevent ghosting you will need to use only choices from a single row or column. Since a joystick cannot be both up and down, nor left and right, simultaneously, up and down can be from a separate row/column, and same for left and right.

You can put your non-gaming keys (for controlling your front-end, choosing games, etc.) on a separate row/column, since these will most likely not be pressed during gameplay. This doesn't apply to coin-up and player keys, since these are often pressed during gameplay.

If you really want to use a keyboard hack, you should look for a matrix with the most pins on a single side. e.g., a 12x12 matrix can support 144 keyboard keys, but only gives 12 non-ghosting keys. A 16x8 matrix can only support 128 keyboard keys, which is less, but can support 16 non-ghosting keys, which is more. It looks like your keyboard has a 20x8 matrix, providing 20 non-ghosting keys. I don't believe I've ever seen a matrix side with this many. What keyboard is this?

Hope this helps.

Mario

[JustMichael]

Even if you find a matrix that has no ghosting most likely the keyboard hack will have a limit of how many keys it will send at once. This means if the keyboard can only sends 6 keys at once then both players get up to a diagonal move and 1 button (without interfering with the other player).  Up and Left and 1 button = 3 keys, now x2 (for 2 players) and you get 6 keys (the example limit).  A keyboard hack can be a great thing for a 1 player cabinet but if you want more than 1 player at once, I would recommend an encoder.  I have an ipac in my cabinet and I have not had a single problem with it.

[bufalo]

Yeah, itīs decided. I will hack one of the mentioned pads for player1, leaving two butons for twe first player2 ones and will leave the hacked keyboard for the rest of player2 controls and service keys.
Another problem appears with some emu like project64. At least 2 keys that I considered safe (both on player1) are used by the gui/emu and canīt be mapped: F5 to save and / to open the gui. So many reasons at last drive me to combine both hacks, making the choice of keys in the keyboard very easy (I hope).

If you really want to use a keyboard hack, you should look for a matrix with the most pins on a single side. e.g., a 12x12 matrix can support 144 keyboard keys, but only gives 12 non-ghosting keys. A 16x8 matrix can only support 128 keyboard keys, which is less, but can support 16 non-ghosting keys, which is more. It looks like your keyboard has a 20x8 matrix, providing 20 non-ghosting keys. I don't believe I've ever seen a matrix side with this many. What keyboard is this?

Hope this helps.

Mario

Sorry, I donīt have the keyboard chasis and donīt remember itīs model. Nothing on the PCB or the sheets. I thought I was lucky when I opened it and saw that config, but finally seems like not. Maybe for any simpler configuration like JustMichael says.

thank you all very much guys
p.S:I hope next weekend (even before if I could) i have fully functional mi control panel (athlon inside xD) and show you any photo of what i call "engendro", spanish word for things like i do.
http://cdn.extracine.com/files/2008/10/goonies_sloth_1024.jpg
this is a engendro
chocolaaate