Self centering hack

[onemoretime]

My first how to. This uses the controller and pots linked in Protestari s 5200 podcast. After the dremmel work, it sandwiches nicely between the upper and lower housing. The original type flex circuit worked just fine for me. I had tried using the original boot, but for me it was way yonder to stiff to use in that fashion.

[onemoretime]

Servocity joystick part number 605614. Pots are found here http://www.ebay.com/itm/2Pcs-Mini-Pots-18mm-Split-Shaft-Audio-Taper-A500K-Electric-Guitar-Potentiometer-/192029611906?hash=item2cb5db5782:g:94kAAOSwZ8ZW4fY~

[onemoretime]

Oh, and in my case I had to remove the ball temporarily from the stick to aid in my mockup. It was held in by a dab of glue.

[H454]

5200 Podcast thread on AA:

https://atariage.com/forums/topic/255618-the-atari-5200-podcast-new-podcast/page-8

Link on the thread to page of the person who did the mod/ joystick with full parts list:

http://retrogame.cyberphreak.com/2017/07/22/5200-controller/

 

So, do the Servocity joystick use pots with a more standard shaft size?

I had tried one of the adafuit ones, but the pot shafts are very small (Like 3mm D shape). And pots I could find need to be severely modified.

 

Do the 500k pots install with out modification? The 500K pots has a large enough sweep? Sometimes 750K is needed for these kind of mods because the joystick don't travel far enough in one direction or another.

Sorry for the questions, but I'm just surprised if anything "just works"when it comes to an Atari 5200.

[BigO]

I'm interested in hearing how well this actually works. I do believe that the stick can center itself and, consequently, center the pots. However, given the capacitor charging analog to digital scheme that the 5200 uses, I've always been skeptical about the effectiveness of physically auto-centering the stick. It seems likely to me that there will be inconsistency from game to game, though I don't know if it will be enough to make a difference. Maybe the dead zone is big enough in all games to compensate for discrepancies in position detection.

 

I think over time the center will drift, as far as the console is concerned. I'd expect some sort of trimmers to be required for a controller like this to be consistently functional across consoles, in lieu of having to open up the console to make the adjustments.

 

I wouldn't be surprised to find out that self-centering mechanics were left out of the CX52 for more reasons than just cost saving. I'm not betting real money on my suspicions being proven correct, though.

[onemoretime]

I ll be answering yall by the end of the weekend fellers. I ve got a bit of a bull by the horns as of late.

[H454]

I wouldn't be surprised to find out that self-centering mechanics were left out of the CX52 for more reasons than just cost saving. I'm not betting real money on my suspicions being proven correct, though.

 

No, with Atari, cost saving is always the reason.

 

 

I'm interested in hearing how well this actually works. I do believe that the stick can center itself and, consequently, center the pots. However, given the capacitor charging analog to digital scheme that the 5200 uses, I've always been skeptical about the effectiveness of physically auto-centering the stick. It seems likely to me that there will be inconsistency from game to game, though I don't know if it will be enough to make a difference. Maybe the dead zone is big enough in all games to compensate for discrepancies in position detection.

 

I think over time the center will drift, as far as the console is concerned. I'd expect some sort of trimmers to be required for a controller like this to be consistently functional across consoles, in lieu of having to open up the console to make the adjustments.

 

 

 

 

There is a "dead zone" built in to the 5200 ( like at the 250K, with about 100 to 150K window), thats why I was asking about the pots/ sweep.

Also, with these joysticks, the return springs can be removed too (no centering if desired - the rubber boot has some spring, but not much). The pots on these joystick can be rotated to calibrate the center of the sweep - like the slides on old pc joysticks.

 

If there is ANY analog joystick under $30 with a relative easy pot swap option, I'll try it.

I'd rather make my own for 1/2 of what rebuilt 5200 controller costs.

 

I've played with other cheap joysticks - I Just want one I don't have to modify the pots.

 

It would be nice if the guy that made the stick in the box from the links, had some pics of the inside, not just a parts list. Though that is help for people who haven't read EVERY homemade 5200 controller post On Atari Age( I almost have).

[Osgeld]

Audio Taper pots also make me tweak a bit, its not the same as a Linear pot

 

Linear's like used in game controllers go from nil to max at a theoretical diagonal line, so at 50% rotation its more or less 50% tween 0 and Max with tolerances of course

 

Audio Taper pots, thanks to how decibel levels work give the same min and max greatly exaggerate the middle regions of the pot, and when used in a controller situation means its pretty much digital with a very tiny zone of actual analog control

 

so if one takes a linear and rotates it 120 degrees you will get 50% of the resistance, with an audio taper its ~ 18-19%

 

[BigO]

 

No, with Atari, cost saving is always the reason.

 

 

 

 

 

 

There is a "dead zone" built in to the 5200 ( like at the 250K, with about 100 to 150K window), thats why I was asking about the pots/ sweep.

Also, with these joysticks, the return springs can be removed too (no centering if desired - the rubber boot has some spring, but not much). The pots on these joystick can be rotated to calibrate the center of the sweep - like the slides on old pc joysticks.

 

If there is ANY analog joystick under $30 with a relative easy pot swap option, I'll try it.

I'd rather make my own for 1/2 of what rebuilt 5200 controller costs.

 

I've played with other cheap joysticks - I Just want one I don't have to modify the pots.

 

It would be nice if the guy that made the stick in the box from the links, had some pics of the inside, not just a parts list. Though that is help for people who haven't read EVERY homemade 5200 controller post On Atari Age( I almost have).

Given the way the analog to digital conversion works, I don't think the dead zone is built into the actual console. I'm no expert on the internals, but I don't recall ever seeing that the BIOS was responsible for interpreting any of the controller input and that's the only place I can think it would be done.

 

So, I imagine that it would have to be the game software that's implementing the dead zone. That's why I tend to expect some inconsistency. In a different way, I ran into some significantly different implementations when I built a custom 5200 controller (http://atariage.com/forums/topic/117809-homebrew-controllers-modernish-5200-and-vectrex-digital/). It used a technique of adding external capacitance to compensate for the pots being of smaller value (lower resistance = faster charge, larger capacitance = slower charge). I was using 150k pots which worked well for some games, but not others. I came to the conclusion that the poorly performing games sampled the pots much more frequently. So much more that the discharge circuitry couldn't dump the charge fast enough with the added capacitance in place.

 

That shouldn't be an issue at all for you, but just pointing out that all games are not created equal.

 

I like the joystick you're using. Is there an external means of rotating the pots for calibration, or do you have to get inside the controller to make those adjustments?

[7800fan]

I had looked into making replacement self centering replacement. There are many analog joystick on various markets like replacement PS and XBox controller and Avr/Arduino but they all used 10k pots and I have not been able to find a 500k pot in the correct size and shape to swap those on analog sticks.

 

It's on the back burner as I got a few other projects to work on including finishing up and testing extra Masterplay clones to sell.

[Osgeld]

I thought about a thumbstick game pad type controller many times in the past when bored, but never bothered to look much past "I bet I could make that work, but I dont have a 5200 or much motivation to make a project out of it"

 

on other analog controller systems you can just add a butt load of capacitance to make up the difference, but those are quad 555 arrangements like in the IBM pc and Apple II so that works, I have no idea if the 5200 follows that or if its got some integrated ADC in its guts that does the magic, which wouldn't work with the capacitance trick

[BigO]

I thought about a thumbstick game pad type controller many times in the past when bored, but never bothered to look much past "I bet I could make that work, but I dont have a 5200 or much motivation to make a project out of it"

 

on other analog controller systems you can just add a butt load of capacitance to make up the difference, but those are quad 555 arrangements like in the IBM pc and Apple II so that works, I have no idea if the 5200 follows that or if its got some integrated ADC in its guts that does the magic, which wouldn't work with the capacitance trick

I couldn't even come close to making 10K pots work with the 5200 by just adding capacitance. It sorta worked with 150K pot thumsticks. But, there isn't a surplus of MadCatz Dreamcast controllers floating around to scavenge for those.

I have another plan to make the 10K pots work. Someday. When I'm bored and have finished the umpteen other projects I have pending.

[Osgeld]

well depends on the circuit on the input side, I happily used 10k pots on my apple 2 with 36nf added onto the xy lines, if it is a 555 type setup like the A2 and the PC then its just math if its not then its a magic trick

 

anyone want to donate a working 5200? cause unless its practically free I am not buying another one ... the last one I sold off was like 14 years ago due to those damn controllers

Edited October 1, 2017 by Osgeld

[H454]

Speaking of thumbs sticks pots, did that setup with the psx controller adapter ever get off the ground / is it still a around?

I saw a couple of threads with a lot excitement, but no payoff.

https://atariage.com/forums/topic/169356-playstation-5200-adapter-thread/?hl=%20playstation&do=findComment&comment=2514989\

http://www.multigame.com/mastercontrol5200.html

It looked like he had quite the board made for it.

 

Also, these pots are the same size as the parts listed, but linear taper:

http://www.ebay.com/itm/Musiclily-Guitar-Mini-Size-Pots-B500K-Long-Split-18mm-Shaft-Linear-Taper-Potenti-/222622682421?epid=1512232746&hash=item33d5588d35:g:W-gAAOSwAFNZnqQZ

Side note,

After going through like 20 5200 controller threads ,There has to be well over 10 different "half" analog and digital (like at least 5 different wiring diagrams for digital) homemade controllers.

It seems like a 5200 aftermarket/homemade controller is never going to be cheap or easy.

Edited October 1, 2017 by H454

[BigO]

well depends on the circuit on the input side, I happily used 10k pots on my apple 2 with 36nf added onto the xy lines, if it is a 555 type setup like the A2 and the PC then its just math if its not then its a magic trick

 

anyone want to donate a working 5200? cause unless its practically free I am not buying another one ... the last one I sold off was like 14 years ago due to those damn controllers

I don't know the Apple stuff. But, I recall PC joysticks being a voltage divider setup as opposed to the capacitor charging scheme that Atari used.

It takes .22uF to use a PC joystick with the 5200. The PC joysticks typically had 100K pots, some had 150K. We're talking an order of magnitude lower resistance than the stock sticks. It works fine on many games, but not 100%, so I abandoned the idea of producing a custom handheld controller until I find time to pursue a better solution.

 

If by "magic trick" you mean some active circuitry more complex than hanging additional capacitance on the X/Y inputs to compensate for the lower resistance then I agree.

 

Some reference material:

An implementation of an adapter to use a PC joystick: http://www.atarihq.com/5200/5200faq/06_04.html

The interface/cap discharge circuitry in the 5200: http://atariage.com/5200/archives/schematics/Schematic_5200_IO_Low.html

[onemoretime]

 

Well, having a bit of a setback as of right now. Here's the pots that where listed in the link. As shown, it s going to take lots of dremmel modification to work, and it s going to be lots tighter that anticipated. I ll continue to post as progression takes place.

[Osgeld]

it s going to take lots of dremmel modification to work, and it s going to be lots tighter that anticipated. I ll continue to post as progression takes place.

its fairly rare that something worth doing is easy

[H454]

So this joystick uses pots with the same shaft size as the other MUCH cheaper ones:

http://www.ebay.com/itm/360-2-axis-Sealing-10K-Joystick-Potentiometer-Wont-Reset-for-Lighting-Console-/252531595122?hash=item3acc0e5772:g:qYEAAOSwTA9X7LZp

Basically search analog joystick and buy the cheapest - they also about $20 on Digikey.

The shaft is a little more than three 3mm(3.2?), The real problem is that the joystick only turns the pot in a range of 90deg.

These pots use the same shaft size - cut to size and use a dremel to grind a d/half shaft.

I've done a pot swap on these to 500k, but the moment range isn't large enough.

[yell0w_lantern]

image.jpgimage.jpg

 

Well, having a bit of a setback as of right now. Here's the pots that where listed in the link. As shown, it s going to take lots of dremmel modification to work, and it s going to be lots tighter that anticipated. I ll continue to post as progression takes place.

Maybe you could disassemble the housings and mod the 500k cermet to fit the smaller housing?

 

[EDIT]

What are the dimensions on the smaller potentiometer in your picture?

Edited October 5, 2017 by yell0w_lantern

[David Alexander]

My first how to. This uses the controller and pots linked in Protestari s 5200 podcast. After the dremmel work, it sandwiches nicely between the upper and lower housing. The original type flex circuit worked just fine for me. I had tried using the original boot, but for me it was way yonder to stiff to use in that fashion. image.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpgimage.jpg

 

Wow this look great.

[Bryan]

"Self centering hack" sounds like an insult.

[7800fan]

"Self centering hack" sounds like an insult.

 

It is an insult to whoever thought non-centering version was a good idea. Whose idea was it anyway and how did that get approved?

[SoundGammon]

Atari, at one point, was designing a digital joystick for the 5200.

 

Anyone have any details/info on this?

[H454]

Which one? Are you talking about the one I linked to? Like the 14th post?

[Swami]

Probably not much help, but it looks like Atari was working on a digital 5200 joystick that a prototype exists of, but was never sold. It does not use a pot. Apparently, it worked well.

 

http://www.atarimuseum.com/videogames/consoles/5200/5200joy.html