Hi,

I made significant progress with my project of total replacement of GP2x's stick. I have now a prefinal version of my logic converter and successfully connected it to GP2x and controlled it from external pad.

First the circuit board:


It's using socket adaptors for chips because I would like to be able test different ones. Final (production) version will have chips soldered directly and will be shrinked by few mm.
(don't worry - it will fit inside GP2x without any problems)

Now the pad - it's Saitek P2500 hacked quickly to act like a input device for my logic converter:


Time to make some wiring into GP2x itself. There wasn't any soldering here just smart trick to connect to existing pins at the back of GP2x's mainboard:


Does it really work? Yeah and everything is powered directly from built in AA batteries in the GP2x (Saitek pad is used only for its switches - it doesn't consume any extra power):


Dreaded diagonals works of course too but behave very nicely now


But to the point - the games. Prince Of Persia running in Outcast first. Basically unplayable using stock's stick. How it handles now? As it should - all problems with accidental jumping, hitting undesired directions and other crap are gone!


Turricans... I'm very big fan of these and Atari ST versions are pretty good. Not that terribly bad with original stick but... running and jumping now is... delicious?!


Another trouble maker - the Nebulus - very hard to play with you know what. Fixed!


Gods is another my favorite of all times. Really great on the Atari ST. Awesome graphics and animation. Played it for few minutes using the P2500 pad. I don't have to tell how it was, have I?


Now the bad things...

No bad things except that I still doesn't have a pad or stick what would fit inside GP2x and would be good replacement for the stock one. Any ideas are very welcome.

Of course my logic converter works only for stick - it's not universal interface for all GP2x's buttons. That wasn't goal of my project and adding such functionality is trivial because there will not be need of any signal translation (just connecting more wires).

The good things are:

- my logic convert works and works well
- it will fit inside GP2x
- it is powered directly from batteries and it can run even at 1.5V
- it is compatible with any 4-switch based pad or joystick
- it can be used simultaneously with stock stick (for connecting external pad like in my experiment)
- it doesn't require soldering to be connected to GP2x's mainboard (because the stock stick's pins are long enough to use different method)
- prefered method of removing original stick is to just cut it off from mainboard
- fitting a replacement might not require soldering except for wires to the logic converter. But how exactly it should be done is unknow until replacement will be found

That's all for now.

What are you thinking?

If you want to experiment yourselfes I'm willing to make some units for you.

Now that looks like fun! How easy was to solder straight to the GP2x board?

Gotta say you must have had some bottle to try that.

Nice one!

Nice work Radek, I'll ask around about a stick see what i can find.

I'm gonna hold out until this is more complete but I'm looking forward to the end result! Also, have you looked at the NGage and Game Gear Dpads as suggested? If so, are they unsuitable for some reason?

Nice work. I would check into those "mini" gamepads that are available for laptops. Some of them have pretty tiny d-pads, and likely tiny contact boards.

Glad to see that you have got something working now, as I know you have been putting lots of work into this as well as other projects.

That's really awesome.

Like I suggested in the old thread, take a look at N-Gage pads.

Good, finally a proper Dpad.

All I can say is ewww Saitek, bleh... (it was cheap right?)

Also I was thinking...

DaveC has these custom joystick cap things...

we are building our own custom replacment board/adaptor/module:

Why not make the 'top' part of the dpad fit thru the small hole for the old joystick,
and use a carbon membrane pad with a mass produced pcb.

It has a matching bottom part, that it could be screwed/glued onto.
the bottom part makes contact with the carbon pads and control PCB.

http://www.olimex.com/pcb/index.html for the PCB. (they are supposedly the cheapest)

for the membrane pads... there are LOTS of manufacturers. (LOTS... looking may take awhile)

I'm just hoping we get to the point where I plug in a USB gamepad and don't need to rip open the GP2X the fix the problem.

Cool, now you should do a test of battery life. Use the same exact batteries charged for the exact same time and let a video loop or something. Test without powering the chips and test with the chips. I would be interested to know the actual difference in battery life. The difference SHOULD be not much but you never know.

First thanks for good words!

And who made me Guru so suddenly!?

Now it's time to answer some question...



It wasn't because there wan't any soldering done on GP2x's mainboard.
It isn't necessary.



I was looking at them but...
There are some issues what I have and don't know how to solve them.
First is the front panel of GP2x - what to do with it? Drill or cutoff? I will
ruin my GP2x trying as I don't have skills for working with plastics.
You know - I would like to use my GP2x as usual and I can not go too
invasive. Therefore I'm asking others for solution of that problem. I will
happily made custom PCB for any idea.

Personally I would prefer an another stick but with 4 proper microswitches.
This would be most elegant solution imho. Not that good as a dpad but still
far better than stock stick.



Yes of course but it's quite decent and comfortable for my hands.



A good idea!!

However I there is problem with needed parts. I can only buy what I can find in available shop - making custom plastic parts is out of question for me.



Thanks for the link. Having more choices for manufacturing is always good thing.



I'm hoping for that too but unfortunately it will need software support (perhaps could be done via driver in the firmware?) and probably USB powered breakout box. It'd be real great for playing games when connected to a TV for sure.

I was using external pad because I didn't have any other controller but I wanted to make the final test of my circuit.

The ability to connect external controler will be just additional possibilty.

For soldering (and such things) I wasn't soldering anything inside GP2x to connect wires. There are other, easier methods.



Why I was expecting that question from you?

Let me say that power consumption is counted in µW per chip. But I just turned my GP2x on running Noiz2a with circuit being powered up.
(actually there are more factors in cmos based chips to consider like a freqency of operation - it can increase power drain significantly after 500-1000KHz... but I doubt that you can move your fingers that fast )

Damn my overactive imagination

It looks great, although I would have thought using the Dpad in one hand and the controls in the other would be rather uncomfortable.

That was for testing only if it works in actual aplications and games. Don't assume that it will be so! I just hadn't any other controler to use for that purpose. But I must say that even in such awkward position I could finish level in the Prince Of Persia - a feat what was impossible for me using stock stick.

The taste of improved control was great... but still there is some work to do with mechanical replacement of GP2x's stick. At least it is starting to be real possibility.

sounds great..
hope we find a good replacement pad/stick soon..
cant wait to mod my gp2x

To answer DaveC's question about power drain of the converter circuit:

My GP2x worked over 3.5 hours using fully charged GP2100 batteries running noiz2sa game with it.

I will try later to run it without it but I doubt that difference is measurable.

hmm what about the dpad of the original cube controller its quite small...
i have a broken one lying arround here (the anologstick is broken)

Wow! that's some serious modding. Congratulations Radek! I can't wait to see how this pans out..

Radek, how much do you think your gadget will sell for (£), with/without a D-pad? I presume you are intending to sell them eventually?

Looking good, damn good.

I got a couple of the PCB joystick units earlier in the week, but this weekend has been kind of a write-off, so hopefully I'll have time next week to try mods on those to try and improve the feel.

One of my intentions is try a restriction mod to turn it into a 4-switch unit, and make use of your circuit, Radek, so that the external appearance is unmodified.

My other thought was to use a hole cutter or stepper bit to cut out the original collar, and replace it with some kind of custom clip-in or screw-in job.

However, that's my problem: Too much thinking and not enough doing!

I'm hoping to have my own GP2X units within the next week or so, and then I can take them apart and do some of my own hacking, as well as see how much space there is inside the casing. Perhaps it might even be easy enough to cast new ones, if there's not too many fiddly internal supports.

The only drawback to people like myself buying these additional sticks is now perhaps the designers in ALPS are sitting back thinking, "Hey, we must be geniuses. Those joysticks are selling like hot cakes - We must have done something right!".



Looking forward to seeing more of your work...

Turning the current stick into a 4-switch would be difficult, you will see when you look at it. The best way if you are going to use the current stick and not replace with a pad would be to rotate the stick 45° to eliminate the diagonal bias, then shim the "hat" closer to the contacts to reduce dead zone. A metal spacer could be placed between the hat and the top metal cover.

Looks to me like the easiest way to do this is to have four switches in a plastic molding that covers the original hole.
It would be very cheap and work very well, The only drawback really is it will be a little higher than the stock stick.

Look at the pic in Daves Sig, We dont need to just cover the hole we also have a big square surrounding the hole of the stock stick.
It would be very easy to make a mock up on a piece of wood, Cut the wood to match the entire left hand side of the GP then drill 4 holes for the switches.
Now just trim away as much of the extra wood as you can.

I would do a mock up but i hardly play with the GP cause of the stick so i lent it to my business partner to go to Thailand with (19 hour flight)

A small aside, Can you believe you have inspired me to get the iron out and carry on with my synth
cheers Radek

PS I will do a mock up when i get the bugger back
PPS I'll go through the new Digikey catalogue, I seem to remember it coming a week or so ago, I'll get back to you on that though

So are you going to leave it like that, external, or are you going to somehow get that saitek controller inside the GP2X? Because that would be quite inconvenient to have to use an external controller.

@Anhaedra: If you had read the rest of this post you would have noticed that the external-ness of the controller is only for testing his custom switch setup. Radek is looking for replacement stick to use and hopefully one day we can custom mount them ourselves.

Good progress on this Radek, the stick is definately one of the major setbacks for me with my 2X. It would be lovely if it was anywhere as good as the GBA D-Pad, but from the sounds of it, it seems to be a totaly different setup inside the actual unit.

Good luck anyways. Do keep us updated.

First to DaveC:

The GP2x running noiz2sa just passed exactly after 3.5 hours without the circuit being connected. Unless we want to count single seconds then the effects of power drain of my converter are insignificant.



Yes I'm going to offer them.

And I'm hoping to be able to make two version: dpad/stick/converter combo and just a converter.

For the price... it will depend on the demand and the deals what I will be able to make with one of specialized PCB manufacturers. Making everything in house takes too much time except for prototyping.

I'd like to tell you exact price figures but I can not yet. Sorry.
(because I simply don't know how what my costs will be at this point)

Then again I don't know what demand will be and how units I could sell.
This will be most important factor of the final price.

At worst if the demand will be low I will just make few converters for ones what want to make theirs own mods.
But I see more people are interested in the complete combo solution.
(and for making such one there is still lots of work to do)

Anyway in the days I should have better idea of the costs.



Your good words are very motivating. Thanks for them.

Radek - most excellent progress.

Count me as 1 customer - i want this for my GP2X.

As an aside, how much more expensive would it be to add an external port to connect an external pad to ?? Would be good for using when connect to a TV.

I don't know the technical details ( i'll take one apart later ) but could a 'stick' from an N64 controller be used ??

Just a thought.

Anyhoo, keep it up.

since we use linux you could just connect a usb pad.. ok software has to support it but thats not that hard...
ou would have to wire on every button on the gp2x, you can easily kill the thing by doing something wrong.
i dont think its worth it.

EDIT:
btw, i think i almost finished my replacement dpad, hope it fits in the gp2x in the end. like i said before i used a gamecueb controller (i had one with broken analog stick), a bit expensive to buy a new one just for ripping it apart... when i have all contacts working again i will post pictures...
cant wait to get this device

EDIT2:
ok here first pictures..


there is a small stick for holding the mainboard, this one has to be removed.


after that the dpad should fit in..


in the end it should look like something like that, but i will paint it black.

the dpad is working... now i need your device Radek and see if everything will work like i thought

Great job, Radek.

I’ll say it again… I’m looking forward to portable retro-gaming and having a comfortable 4-way d-pad is a must. Hurry up though or I might be tempted to spend my cash on one of those DS Lites when they hit North America. No pressure, Radek… no pressure. ;-)

He is not working for GPH btw.

Sonic-NKT - Using a Nintendo D-pad is logical (are you using the SNES, NES, Gameboy (mono/colour), N64 or other D-pad (they are all slightly different sizes).

How about the centre button switch? No issues with 4-way instead of 8-way (8-way is hard to control, I find), but you need a centre button!!

Using a Nintendo D-pad requires careful and exacting positioning as it is purely a PCB unit - how would the contacts be soldered?

Other issue is this is not a commercial unit, in the respect that the Nintendo D-pad can't be sold by people (Nintendo wouldn't like it I am sure) and you can't make a D-pad too similarly to theirs : United States Patent: 4,687,200 : patent
There are ways around this of course, which means a hand-made unit which works differently ... I am in experimentation at the moment for making such a unit - will expand more in due course ...

Do we really need a D-Pad? I'm cool with whatever you guys cook up, but wouldn't it be easier to just make a nicer stick, something like the NGPC's?

That patent has to be expired or at least damn near. It was filed in 1985 for Christ's sake.

Right, the Neo Geo Pocket Stick (with microswitches) was really great. I'm dreaming about this stick on the GP2X...

I tried to find the references but I neverfound it, maybe this part was designed/manufactured by SNK.

like i said my solution is not a method for everyone, it to expensive and not worth it...
the gamecube has the smallest dpad (perhaps the gba micro has a smaller one but ripping that apart woul just be totally stupid)
about the contacts, yes it was quite hard but i found a quite good way..
hmm kind of hard to discribe my english isnt that good, atleast for technical things.
i will show you some pictures later.

Time for small update...

Just found some pads very similar to the nes/snes ones (they are looking like clones) and probably aren't of high quality. But were dirt cheap so at least I will not have to constantly rewire my Saitek Pad for testing.

I have info from one pcb manufacturer who I was asking for. It would make my units but I would have to buy over 50 of them. Not realistic for first run...
(but I was asking other companies and I hope to have more info soon)

For N-Gage QD pad I also have source but these units are actually with keyboards included and very expensive. I will not buy one just for testing purposes but will search for better offerts again.

What else?

Not much really (yet).

I will query more companies for parts thought. Will have to buy some more cmos chips anyway.

yeah 50 are a bit much.. this is not a easy mod and many wont do this to their gp2x... atleast not on their own.
anyway i hope you find a way to produce sone a first run 10 or something like that.
i really want to try it.
cant wait to kill my gp2x

As many cunning people have suggested; drill out the area where the dpad will hit the plastic; then
carefully sand it down.

Its labour intensive, slow, and prone to leaving jagged edges. Unless someone makes a custom moulding:

(ahem ....DaveC... )

Take the Dpad '+' design and flatten the underside so its curve matches the 'top' of the GP2X joystick depression.

Drill 4 small holes into the top panel of the GP2X where the 'center' of the pad triangles would be (on a Gamecube/SNES/NES type pad).

The custom Dpad will have 4 small 'pins' that poke thru those holes and allow a microswitch to engage.

The center on the dpad is supported with a rubber column or spring. (or something)

The only thing I don't know how to figure out is what the Dpad PCB rests on. (if not annother platform held up by metal pins from the old joystick connectors.)

Microswitches are being used in this case because I think they will give a more positive feedback to the user AND work better (mushy carbon pads dont work well with sharp plastic columns poking into them). Oh, and a single external switch added to the outside of the case. (drill a hole for one of those small momentary push buttons, near the top right perhaps)

I think it could really work, now. Keep thinking and working guys / gals. We are getting closer...

Well I've discovered something that could really help with the custom plastic Dpads:

http://www.shapelock.com/index.html

A plastic that can be easily worked with only hot water.

Check it out!

I wonder, if the microswitches inside a mouse might be good for this? I have few old ones...

I will able to make few units anyway so don't worry. Just was looking around as I'd strongly prefer to make PCBs with solder mask (it's more reliable, looks nicer and is easier to solder) as I can not make such ones at home.



Another solution would be complete change of GP2x's case...
It'd be very doable as the GP2x's mainboard is very simple (and it's good thing) design. Should not be hard to make but unfortunately this is beyond my abilities. But perhaps there would be some market for different "skins" for GP2x?



That's actually quite easy part - after removing the stock stick (it can be just cutted off the mainboard and should to preserve its pins at back side) there will be plenty space to mount your own small PCB board to support mechanically new controller.



I'd prefer microswitches too but membrane ones can work good also.



Just found some other parts needed... not ideal but not expensive either. They will be very helpfull...



Has been anyone using it? How really is it good?
It looks very atractive and could be very handy.



You might experiment but plain microswitches are easy to buy.

EDIT:

Just found an N-Gage keypad for not that bad price. Are these serviceable parts with actual switches or not (they can works by themselves or there is need to make a PCB with contact pads?)

Hi,

For PCBs you might want to check this crowd out. I haven't tried them myself yet, but I put them into my bookmarks last year after seeing some favourable mentions.

http://www.pcb-pool.de/

Also, it looks like the shapelock plastic is just a rebranded "Polymorph" that Maplins (in the UK and Ireland) sell. It's good stuff.

It's quite strong when you have a decent-sized lump of it, but when it's thin ( < 0.5mm) then it does get quite flexible which can be a bit of a drawback. On the plus side of that, it can be stretched and flattened while soft if you need to make cable quides etc.

It's great for prototyping parts or making custom mounts. You can use it to copy parts as well: If you make a warm lump of it and press it onto the part you want to copy (i.e. a d-pad) until it cools, then you can use that as a mould for casting a copy, either from resin (you might need to use silicone spray) or more plastic. This is within shape limitations of course, but there are all sorts of methods to get a full mould.

It cuts quite nicely with something like a Stanley knife, if you need to do further shaping on it.

I originally bought it with the intention of prototyping a project, and I've ended up using it for all sorts of other things.

Hi,



I had a look at the internals of one of them today and I have a few ideas, but I'll have to try them out and see what works best. One of the things I'm going to try doing is to put a thin layer of solder on the circular edge of the contactor and file it back down to more of an octagonal shape to match the outside, just to see how that behaves. This should also reduce the throw length by a noticeable margin because of the extra metal, and I would guess with ROHS-compliant solder, it should wear pretty well (if it works!)

From looking at the way the contacts are arranged, and from looking at a (pretty shaky) picture of the GP2X circuit board I found on one of the forums, it looks like it might not be possible to just rotate the unit. :-(

Also, correct me if I'm wrong, but from the picture it looks like they (GPH) have actually mounted it on the PCB at a slight angle?

This is what I love about these boards - the mountain of knowledge, and people wanting to help!

The link to Maplin's PolyMorph is:
http://www.maplin.co.uk/Search.aspx?criter...=15m3&source=15

Excellent!

I also found source of least expensive N-GAGE (classic and QD) pads finally! What are you thinking about first N-Gage pad? They are very cheap now but do look decent.

Could someone provide me with pictures of backsides of these pads?
(and other info like exact sizes)

Soon I should have more parts to play with. I will able to think about drilling gp2x's case then.

I was originally thinking of soldering some very thin pieces of sheet metal to the ordinal contacts. That would solve two problems. It would increase ordinal bias, plus the thickness of the metal would reduce the dead zone as well.

Hi,



I know where you're coming from all right. I was trying to figure out the exact mechanical operation of the joystick, and it's more complicated than I first thought, as it basically involves the stick driving a lever, with the lever having two sliding fulcrums. The bottom fulcrum drives the contactor down onto the appropriate contact at the base. The spring around the outside of the contactor acts as the opposing force to ensure that only part of the contactor touches down. (You know all this already, I'm sure, but hopefully this will benefit anyone else reading who might be wondering...)

I drew myself a diagram to try and clarify it (this is just something knocked up in DPaint, so it's somewhat impressionistic.)

I'm looking at it from the point of it being a single-axis switch, with a 360 degree range of rotation about the y-axis. (For simplicity's sake, I'm also ignoring the switch in the centre of the base, which also acts as a restraint to stop the stick pushing the contactor all the way down.)



From looking at it pretty closely, I have a feeling there is going to be very little room in there for shims etc., which is why I've given up the idea of a slotted film to overlay on the contacts, as any (non-specialist) film thin enough to allow smooth transitions between directions is not going to last long enough to be realistic in implementation.

I realised that if we go too far in reducing the diagonal bias, we may end up with a lot of dead areas between each of the 8 directions, which could be just as frustrating. I have some ideas involving 8 sprung ball bearings mounted horizontally through the sides, but this is just fantasy at the moment, and probably completely unworkable.

I'm hoping that using solder to build up the contact points and shape them will allow me to fine tune it and find the best shape. Logically, an octagonal shape would be best, but we know how these things usually work out, so...


I'd forgotten that over here, we have Friday off this week. Perhaps I'll have some time to experiment after all!

Another small update:

I just shipped for these pads:


Got them dirt cheap and they are serviceable parts for classic Nokia N-Gage. Not best perhaps but at their price it was hard to resist. Get 5 of them and paid the same amount of money just for postal service.

Here I have something better:


This dpad is from N-Gage QD and people were raving about it here so I will try to get it (it's actually on auction and I'm hoping to get it at reasonable price).

I was also evaulating different chips for my logic adaptor but... funnily these old cmos 4000 series chips what I'm using are really the best from almost every standpoint.
(work asynchronous, have very little power drain counted at µW and are small enough even in DIP version).

And thanks about the polymorph info - it might be very handy.

I have to say... I'm starting to be more confident about this project.

I was going to mention Maplin's PolyMorph, but was beaten to it .
I did stumle across this stuff the other day though if it helps.. PlastiDip
Not sure if it will hold up well enough for coating the actual pads, but it might come in handy for something else.

Nice work so far by the way