Playstation PCB confusion and nuances relating to the PSP

[Xtra_Zero]

I've modded my share of empty boxes + ps2 controller pcbs into joysticks and haven't made very many mistakes.  However, recently the super mega 3rd party (read: china imitation) controllers gave me a less than durable batch, and I fried my share of contact pads on the PCB.  Attempting to fix this, I scratched off some of the insulation a bit higher up on the trace and made another solder joint, but when tested, the button went crazy.  After a few months (I'm a slow learner lol) of trial and error and some research, I found that the reason seemed to be because the black semi-conductive material covering the button contact acted as a sort of resistor, only allowing a slight charge through.  I have a few questions pertaining to this subject:

1) Is there a specific resistance that can be used to replace the resistance provided by the semi-conductive material? (with resistors, obviously lol)  Or does it vary by device, considering the different controller models and the ambiguous amount of conductive material applied?  (I tested with a multimeter, but got inconsistent results, probably due to differences in the pressure and angle I applied the leads at (also there may have been another short somewhere >_>;)

2) Does this same principle apply to the PSP Slim?

3) Does the PSP Slim use the same controller protocol as the PS2?  That would be very convenient and possibly save me lots of trouble if it does.

4) Are there 7-pin (minimum, 12 pins if protocol is different :[ ) connectors small enough to be mounted flush or nearly flush on the frame of the PSP?  The only things that I can think of are D-sub connectors and those are way too big :[  I was thinking I might be able to use the extra space in the UMD compartment for some kind of ribbon-cable connector, but I don't know anything about the types of connectors/cables available, so I need a little advice.

5) Would utilizing the USB port be simpler?  Writing PSP driverhacks just for this seems a little daunting.

Thanks for reading, your suggestions are greatly appreciated. :]

[viletim]

You're not making youself very clear... "button went crazy" is meaningless....

Modern control pads all use a microcontroller to read the status of the various buttons, stricks, triggers, accelerometers, etc and transmit the data to a rest of the system via a serial link. This is done so you can have lots of data sent over few wires (or even wireless). Inside the console there's a chip that accepts the serial data and makes it readable by the CPU. Devices which have the controls built in, the PSP in this case, have no need to convert the controls data into serial data and back again, what would be the point?

Some control pads are wired up with one button to one micro input and others are wired in a matrix configuration (pads with heaps of buttons). Neither of these setups involve any kind of resistors in the path of the buttons, it's purely digital. I think what you are looking at inside you chinese controller is just a cheap method of constructing a multi layer PCB. Copper tracks are etched on one side as usual, then a second layer of carbon tracks are printed over the solder masked copper tracks. The carbon tracks have some resistance (you can measure it with a multimeter) but not enough to intefere with the circuit operation. Lots of IR remotes are made this way (matrix config).

[NeWmAn]

Some control pads are wired up with one button to one micro input and others are wired in a matrix configuration (pads with heaps of buttons). Neither of these setups involve any kind of resistors in the path of the buttons, it's purely digital.

What about PS2 (Dualshock 2) analog buttons then?
They are built with 2 sheets of plastic, one has the traces and the conductive material, while the other has only the conductive spots.
Pressing the 2 layers together changes the resistance measured on the contact point.

[Xtra_Zero]

You're not making youself very clear... "button went crazy" is meaningless....

"button went crazy" means just about what it says.  The signal corresponding to the button on the pad randomly went on and off.  There were no loose connections either.  It simply went nuts.

What about PS2 (Dualshock 2) analog buttons then?
They are built with 2 sheets of plastic, one has the traces and the conductive material, while the other has only the conductive spots.
Pressing the 2 layers together changes the resistance measured on the contact point.

This guy gets exactly what I'm talking about.  Now read http://www.gamesx.com/misctech/controltech.htm in its entirety (particularly the last part) and add that to what Niyuuman said, and you may arrive at my position.  Thanks for the info about the encoding and decoding of the controller data.  I didn't think about it that way.  Picture is a diagram of how I think the buttons work in the controller I'm using.  When the signal to the IC goes low, the button is depressed.  Just how low it goes determines how far the button is pushed down.  The variable potentiometer in the image is the button contact mechanism.  It connects the two semicircles, which are contacts covered by a layer of the semi-conductive material.

[NeWmAn]

4) Are there 7-pin (minimum, 12 pins if protocol is different :[ ) connectors small enough to be mounted flush or nearly flush on the frame of the PSP?  The only things that I can think of are D-sub connectors and those are way too big :[  I was thinking I might be able to use the extra space in the UMD compartment for some kind of ribbon-cable connector, but I don't know anything about the types of connectors/cables available, so I need a little advice.

I don't know why you would ruin a PSP , but for small connectors you can hack an old PCMCIA network or modem card, like this for example:


That connector is 15 x 2 mm and has 15 contacts.

You can also hack one of those cheap x in 1 memory card readers (or a MSduo to MS adapter), desolder the SD or the MS socket and use it together with a dummy memory card.

A crazy solution would be to mount a memory stick internally to the psp (I don't know if there's enough space) and use the original MS socket as a connector.

[viletim]

Xtra_Zero,
I completely forgot about the analog buttons (again!). Perhaps you could try measureing the minimum/maximum voltage the IC pin sees. Then you could calculate the value of resistor to switch in and set your prefered 'pressure'.

[phreak97]

unless you really want the stick to work with games that dont allow original psx controllers, use psx controllers to hack up, they have all digital buttons, and thid party ones probably wont have the annoying carbon, alot even have seperate copper pads to solder to so you can still close the controller casing without obstructing the buttons.