Doping Psx Analog Signals?

Started by shadowjin, March 15, 2005, 10:50:56 AM

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shadowjin

This is more like a general request to see if anyone has tackled this issue yet as I'm certainly capable of some trial and error jerry-rigged electronics...anyway...

I've built a joystick using an old psx SCPH 1200 dual shock pad.  In the construction phase, I removed the analog sticks/potent housings completely leaving nothing connected to their 9 pins (3 for l/r, 3 for up/down/ 3 for L/R3)

Well, seems without the potents on there, it defaults to hitting low right on both sticks and sends any sort of analog signal fleeing to the corner of my screen (or input.)

So my question is this - is there a way to dope the signals without having to hook the potents back up.  By doping, I mean by them stay stationary in the middle like they are untouched at all times.  I'm supposing I could test the ohms on the potents and try and dope them accordingly, but I may be missing something that someone else has discovered.

I always come to these boards for my needs but this one I couldn't find an answer on, so here I am creating an account. ;)

Thanks in advance to anyone who can help or anyone who has any clue as to what I'm doing :)

-Jin

NFG

The analogue pots on a PSX pad range from zero to <whatever the max is>, with center position being halfway.  Be removing it you've told the system the pots are at max value all the time, since they're no longer dropping the value to neutral position.

Take the pots and use a multimeter to measure the min and max resistance.  Measure them all to ensure you've got a good reading.  Use a resistor for the middle value, between the pots' min and max, and solder it to the points the pots used to connect to.

That should cure ya.

FYI, this wouldn't have happened with the N64 'cause it uses an optical encoder.  When the system is turned on it assumes wherever the sticks are is neutral position.

shadowjin

That's what I was thinking...

I knew about the N64 sensor and forgot about the ps1/ps2 analog sticks not using that when I removed em.

Thanks tho :)

-Jin