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#76 2015-09-23 03:42:47

Eudimorphodon
Member
Registered: 2014-09-02
Posts: 524

Re: ][ Joysticks and USB adapter

Guess it's a good thing we tested it on my old mongrel, hopefully that covers the spread in terms of model-specific variations in the joystick circuitry. smile

On the topic of a Rev. 2 board layout, I was looking at the thickness of the PCB of the prototype and it seems like it's awfully close to that of the WiiChuck dingus. Sort of wondering again about the idea of building the card edge directly in. (Granted, the WiiChuck bits aren't particularly expensive.) Also wondering if trimmers for the digital pot are worthwhile. One axis reads about 140-something when "centered" on my system, it hasn't been out of the acceptable range so far but I've only tested two games... ahwell, details, details. It's still muchly awesome as is. wink


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#77 2015-09-23 03:49:38

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: ][ Joysticks and USB adapter

Awesome, I'm glad it's working after those pulldowns.

I'll take a look at if, and how much, the wiichuck part would affect the price of the board when I go to do a rev2.

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#78 2015-09-23 15:29:37

Eudimorphodon
Member
Registered: 2014-09-02
Posts: 524

Re: ][ Joysticks and USB adapter

bbraun wrote:

Now that you have it working, are the x/y axis values seeming to work in games?  I'm just wondering about those capacitor values and how important a trimmer is.

I guess we updated at about the same time so I didn't see this; should probably expand on it further. Like I said, it looks like one axis is probably... borderline, in terms of centering. When I can find the time I'll dump a few disks of joystick-centric games and see if it's a problem. (Any suggestions for good test cases?) What are the current values you have on there for the static caps? I was poking through the parts catalog for my favorite local store and they didn't have any trimpots that went bigger than about 300pf; sure it's possible to get bigger but it does make me wonder how much adjustment needs to be allowed for and how to provide that with a combination of trimmers with static caps.


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#79 2015-09-23 16:11:05

bbraun
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Registered: 2014-05-29
Posts: 1,064
Website

Re: ][ Joysticks and USB adapter

The caps on there right now are 4700pF, two connected in parallel should be additive right?

From what I can gather of the USB adapter, the single trimpot on that is feeding into an analog input pin on the controller, which is then using another potentiometer on the digital potentiometer chip to feed into the final output.
The digital potentiometer I chose only has 2, so can't really do that approach without changing the chip, which isn't a huge deal, but I'd rather not if it's not required.  I'm kind of skeptical of using that approach anyway, of a single knob to change both axes, and doing it in software.
I don't really have any suggestions for which games to test, I've pretty much been testing with lode runner mainly because that's what I wanted to play.  smile

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