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Nintendo DSL Breakout Board Issue
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Nintendo DSL Breakout Board Issue

by dpancoe on Thu Sep 06, 2012 10:42 am

My Nintendo DSL touch screen and breakout board just arrived with a problem.

Using the breakout board, I measured about 340 ohms between y+ and y- but found an open circuit between x+ and x-. Very carefully measuring directly at the touch screen ribbon connector, I again saw 340 ohms between y+ and y-, but I also saw about 460 ohms between x+ and x-.

I would guess this to be a problem with the breakout board, but looking at the ribbon connector of the touch screen, it looks like the traces are offset. Meaning: the four traces are closer to the right edge of the ribbon (looking at the faces of the contacts) than to the left. I suspect this may prevent the contacts from lining up with the pins of the connector.

Thoughts?

Thanks,
Don P.

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Re: Nintendo DSL Breakout Board Issue

by adafruit_support_rick on Thu Sep 06, 2012 10:54 am

Can you post a detailed picture, so we can have a look?

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Re: Nintendo DSL Breakout Board Issue

by dpancoe on Thu Sep 06, 2012 11:28 am

Here is a pic...

Thanks,
Don P.

Image

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Re: Nintendo DSL Breakout Board Issue

by adafruit_support_bill on Thu Sep 06, 2012 11:44 am

Very carefully measuring directly at the touch screen ribbon connector...

Were you measuring the ribbon side or the pins on the back of the connector? If you are getting good measurements on the back of the connector, then the problem must be between that and the 4-pin header.

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Re: Nintendo DSL Breakout Board Issue

by dpancoe on Thu Sep 06, 2012 12:25 pm

I originally only tested on the ribbon itself and on the soldered-in header pins. Testing the pins on the back of the connector, I get the same results as on the ribbon itself - implying that the contact between the ribbon and connector are OK. I'm still getting the x+/x- open circuit on the header pins, however.

The weird thing is: when I test continuity between the connector pins and their corresponding header pins, both with the display connected and not, they all appear OK (although the x- pin may be a bit inconsistent, subjectively).

I included the whole breakout board in my earlier photo in case you saw anything wrong with my solder joints. They look fine to me. Should I try de-soldering and re-soldering the header pins?

Thanks,
Don P.

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Re: Nintendo DSL Breakout Board Issue

by adafruit_support_bill on Thu Sep 06, 2012 12:32 pm

The photo is a little dark, but from what I can see, the header pin joints look OK. You might want to take a closer look at the soldering on the socket pins. A bad joint on one of those would be consistent with the symptoms (It would probably become conductive when you poked it with a meter probe).

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Re: Nintendo DSL Breakout Board Issue

by dpancoe on Thu Sep 06, 2012 12:42 pm

Thanks. I only have a low-power magnifier and thru-hole soldering iron here at home, so this might have to wait until I can get to NextFab, hopefully later today.

Don P.

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Re: Nintendo DSL Breakout Board Issue

by dpancoe on Thu Sep 06, 2012 1:41 pm

I was able to fix the breakout board with just a little bit of solder on the x- connector pin.

Now I have it hooked to an Arduino Uno running the touchscreendemo sketch (I eventually want to run it on a Leonardo). By commenting out the threshold IF statement, I can see that the x and y values are changing appropriately, but I'm only getting 0 for the pressure reading. Any idea on what is causing that? I am using a stylus.

Also, exactly which side is the front of the touch screen? The side with the black cover over the adhesive or the other one? Does it matter?

Thanks again,
Don P.

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Re: Nintendo DSL Breakout Board Issue

by adafruit_support_bill on Thu Sep 06, 2012 3:22 pm

Great that you were able to fix that. The adhesive side is intended to attach to the screen. But it should function either way (with transposed coordinates).

By default, the library takes a number of consecutive readings, and if they do not agree exactly, it sets the 'z' value to zero for an invalid reading. Personally, I've had better results using NUMSAMPLES = 1, but the default is 2.

From "TouchScreen.cpp":
Code: Select all | TOGGLE FULL SIZE
// increase or decrease the touchscreen oversampling. This is a little different than you make think:
// 1 is no oversampling, whatever data we get is immediately returned
// 2 is double-sampling and we only return valid data if both points are the same
// 3+ uses insert sort to get the median value.
// We found 2 is precise yet not too slow so we suggest sticking with it!

#define NUMSAMPLES 2

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