Gp2x Joystick Exposed - The Internals

[Radek]

Correct! But what you should do is make connections to all 8 connectors. The X\Y are mapped directly but if a X and Y are hit together, they should short out the straight connections and use the diagonal connection.

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If you design a logic circuit that gives X=sw3, Y=sw1, Y+X=sw2.. and so on you could do it. the 16 way input would be ignored. How good are you at designing logic circuitry? I can't do it. Plus that extra power required... It would be a wire mess and alot of work. It would probably be easier to mod the old stick.

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Wonder what is it?

Tested!

 

[Thraka]

I'll pay 50$ (dollars) to the first person to do a real DPAD. It must look good. And I want a proof of concept design drawing first.

And be fair! If you use something like the logic Radek has designed, split the moola with him

 

[bazuka]

I'll pay 50$ (dollars) to the first person to do a real DPAD. It must look good. And I want a proof of concept design drawing first.

And be fair! If you use something like the logic Radek has designed, split the moola with him

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OOOHHHH... And the mod gets interesting.

 

[bazuka]

Correct! But what you should do is make connections to all 8 connectors.  The X\Y are mapped directly but if a X and Y are hit together, they should short out the straight connections and use the diagonal connection.

​

If you design a logic circuit that gives X=sw3, Y=sw1, Y+X=sw2.. and so on you could do it. the 16 way input would be ignored. How good are you at designing logic circuitry? I can't do it. Plus that extra power required... It would be a wire mess and alot of work. It would probably be easier to mod the old stick.

​

Wonder what is it?

Tested!

​

Radek: What kind of chip is that? Will it fit into the GP2X?

 

[Radek]

Correct! But what you should do is make connections to all 8 connectors. The X\Y are mapped directly but if a X and Y are hit together, they should short out the straight connections and use the diagonal connection.

​

If you design a logic circuit that gives X=sw3, Y=sw1, Y+X=sw2.. and so on you could do it. the 16 way input would be ignored. How good are you at designing logic circuitry? I can't do it. Plus that extra power required... It would be a wire mess and alot of work. It would probably be easier to mod the old stick.

​

Wonder what is it?

Tested!

​

Radek: What kind of chip is that? Will it fit into the GP2X?

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This isn't a chip but a logic schematic. How physically it will look that's depending on types of parts used. There are 8 "AND" and 4 "NOR" logic gates. I could build it using three chips (two 4xAND plus one 4xNOR). I would have to try build it first to know exact size of complete circuit.

Such chip (there must be three of them) looks like:

EDIT: This is first step but what about gp2x's front panel? How a dpad could fit inside and how drill plastic to not ruin it completely?

I will make measurements to see where this circuit could be fitted inside gp2x.

 

[Thraka]

There could always be a small "lump" on the back of the case that contains the chips and the wires and go through the back of the case...

I donno

 

[Jaw]

is there no surface mount equiv of those chips you are thinking about doing? if you used a small surface mount pcb with 4 contact pads it might fit in.

 

[bazuka]

Radek:

Do understand that I'm not trying to defeat your proposal, I'm just saying from my experimentation, there doesn't appear to be much room under there. If you can make it happen, I will happily adopt your design.

With that, the front panel of the GP2X will require a bit of modification as you suggested. I am willing (strangely) to sacrifice cosmetics for better control.

 

[Thraka]

Even if the DPAD piece is raised slightly above the rest of the console, but looks good, I'm totally for that.

The chip though is hard to put in. You could probobly get a smaller chip if you go a tiny bit more expensive... But even then, you'll have to get inventive of where to put it. You might even be able to put it else where in the console! I know it's compact but there migh tbe some room. The other thing would be to build a small compartment that is pretty thin on the back of the unit to house it and just run the wires through the console to the pad and contacts..

Donno just some ideas..

 

[bazuka]

The only place I've seen that can hold anything is between the power and battery LEDs.

 

[luteijn]

race conditions due to path length differences might make things worse..

maybe a prom would be better? 4 address lines, 8 bits of data, less chance of race conditions, only one chip needed.

No time to properly think it through though..

P.

 

[Radek]

race conditions due to path length differences might make things worse..

maybe a prom would be better? 4 address lines, 8 bits of data, less chance of race conditions, only one chip needed.

No time to properly think it through though..

P.

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A good idea!

However it will not be clear what is the best solution until some experiments...
Some dumb issues (but very hard to deal with) might emerge...

For a latency I doubt my circuit will be affected much. Its just three gates in a signal path and every gate has latency of 40ns. And the electrical tolerance of chips what I'm thinking to use is big.

I like logic gates because the circuit itself is a program too. Once designed it's just matter of assembling it. But it's just me.

 

[Thraka]

In the "neat ideas" forum, there's a Dpad hack thread that's discussed a carrier board for a complete replacement of the stick, but it may apply as well here. The problem is finding someone with the balls to try it. I'm considering it.

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Where is that?

 

[Paradox]

way to butcher up your 2x to put a crappy d-pad on it

even if someone did manage to do this, do you think everyone who wants it is going to get one..?

will i be able to exchange my shitty old unit with a crap joystick in for a brand new one with a new stick? if not, i hope they dont make hardware changes.

personally, if im stuck with this stick, ill be really disgusted, the stick is the main part of the console, its faulty, its not my fault, why shouldnt i get it fixed?

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Mine is the same mate, the joystick is simply awfull but as the guy above said there is no way GPH or any of their sellers would exchange our units for new ones if they made a slight mod.

Looks like we are stuck with a joystick that basically is useless for games. Today i let my brother have a go on ghouls and ghosts on the mame emulator....he played it for like 30 secs and said " whats wrong with the joystick".....and i could see that for him to move even left or right was a joke....one minute it would work then it wouldnt.

Brilliant little handheld but the joystick is complete crap IMO.

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yep, i let my little brother have a go of my 2X, any game he tried, even an RPG with simple 4-way directions, he found hard to do, and put it down and went back to playing his GBA, its really frustrating that im stuck with this stick now, and im pretty sad that there was at least no warning from GBAX, seeing as Cragix seems to be quite a nice guy in the community and involved with GPH.

its very frustrating to say the least...

i had thought a few weeks ago this would have all been sorted out once i seen DaveC's joystick configuration image, i thought the dev's would have implimented the best controls from his image into their emu's and programs 2 is best in my opinion, or maybe 4...seriously, correct me if im wrong but if GPH put case 2 or 4 into the "core" of the 2x, so it used either of those controls overiding anything else, the whole accidentily hitting diagonal problem will be solved idefinetly, and there wont be any need for a new joystick (ok, the cap still sucks, buy daveC's or wait for an official cap replacement) but at least the crappy diagonal problem will be solved, right? seriously, whats the problem am i missing something?

 

[Thraka]

I only really see this getting fixed with a DPAD..

I guess another alternative is using an analog stick. It would be just like the DPAD but some sort of controller that just deciphers the degrees and triggers the correct wire that is wired to a direction..

like degrees -25 through 25 = up
26-60 = up\right
61-120 = down

ect.. (just threw some numbers..)


But I think an analog stick would be even more complicated than a DPAD

 

[gaterooze]

I don't see why a D-pad is necessary. The best control I ever had in games was on the C64 with a joystick.

 

[Jarska333]

The best control I ever had in games was on the NES with a D-pad.

 

[Dingo_aus]

If you want to map a new controller (dpad, 4way stick etc)into the existing slot, why not use a microcontroller to interface?

Many have their own internal oscillators, so no crystal needed, draw little power, and could have software debounce etc.

Those pic10F look small enough to snort (you think I'm joking?) and AVR tiny's are small too (smd)

 

[Frank]

The way it works is there is a "hat" that is common and tilts to make contact with contacts in the base. There are 8 contacts in the base. A spring keeps the "hat" from making contact unless force is applied. There is a center blister switch that closes when the brass shaft is pressed. There is no threading and the brass stick and metal hat are keyed so they don't rotate. It is a simple arrangement.

DaveC, how reliable do you think this simple mechanism is? I only ask as mine now, as of about 4 hours ago, has no right movement. What would be the likely cause of this given the arrangement? Great photos BTW.

It packed up suddenly, although since I had it, the diagonal top right hasn't been so good as the rest but livable with, and there's been no problem with right itself until tonight. Could it maybe be caused by something getting in and insulating the connection, or is it more likely to be a connection itself gone bye-byes? I was using it when it stopped working.

There's actually two in the house, mine has "First Edition" on it, but my lads (Santa bought it for him) doesn't, and his seems a little better in the control department.

Cheers,


Frank.

 

[Thraka]

I don't see why a D-pad is necessary. The best control I ever had in games was on the C64 with a joystick.

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I loved playing with a joystick on C64. But the points of contact are much easier\bigger to hit then a miniturized joystick (gp2x) DPAD gives you the precision when small.