Question Need help creating a Wii "tablet"

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Hey guys!

I'm new here and I came for your advise and experiences with portable Wiis end electronics in general! I want to create a semi portable Wii "tablet" out of a Wii with a broken disk drive I got for cheap on eBay. So here are my plans:

I got a 15,6" 1366x768 display from a broken laptop, so I bought a driver board that lets me use the screen with a HDMI or VGA input. So now I want to create a portable Wii with this screen and speakers built in, as well as a battery. I also want to add a kickstand, so I can basically use it like a big switch in tabletop mode. Considering that the device will be pretty big, I don't think that I actually even need to trim the mainboard to make it smaller. I would only go and desolder any ports that I don't plan to use anyway (like gamecube ports). As for the controller I want to use external Wiimotes connected via bluetooth. This all leads me to a few questions.

I want to use a battery, so with a step up/step down converter I would be able to power the Wii from its generic power input. But will this be actually less efficient than using the standard external voltage regulator method, and result in considerable less battery life? Also, can I even use Portablize Mii with a non trimmed board?
The screen I want to use has a 1366x768 resolution with an HDMI and VGA input. I thought about getting one of those cheap Wii 2 HDMI adapters to connect it to the display, considering that the needed space for the adapter really doesn't matter. Would this result in a clean video output? Or would it be better, to make use of the VGA mod and use the VGA input instead? I really want to have 480p output to be able to play games lile Xenoblade Chronicles, The Last Story etc.

I'm looking forward for your support and I will make sure to post some updates if you want to see them. I recently built myself a CNC, so I will make the case of the portable out of oak, I hope it will look really neat!
 

Stitches

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You can use a 16.8v li-ion battery pack to run an untrimmed Wii. The stock Wii regs can run off 10.1-20v IIRC. You'd just have to assess if your driver board can take that voltage. If not, you can 5v mod it and run it off the Wii's 5v line. You could alternatively remove all the onboard regulator components (everything outside the OMGWTF trim lines) and connect a custom reg solution as if you'd trimmed the board. That would allow you use a simpler battery setup with USB-C charge and play if you use a PMS and USB-C PD module.

For video, I'd use the VGA patch. HDMI adapters introduce latency and consume additional power.
 
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You can use a 16.8v li-ion battery pack to run an untrimmed Wii. The stock Wii regs can run off 10.1-20v IIRC. You'd just have to assess if your driver board can take that voltage. If not, you can 5v mod it and run it off the Wii's 5v line. You could alternatively remove all the onboard regulator components (everything outside the OMGWTF trim lines) and connect a custom reg solution as if you'd trimmed the board. That would allow you use a simpler battery setup with USB-C charge and play if you use a PMS and USB-C PD module.

For video, I'd use the VGA patch. HDMI adapters introduce latency and consume additional power.
Thank you Stitches for your fast reply! Does that mean I can simply attach a 16.8v battery pack to the external DC input of the console? That would be really convenient! The display driver runs at 12 volt, I can't really tell if it's able to run safely with more voltage. The 5v mod sounds interesting, but will the internal 5v regulator of the switch be powerful enough to actually drive the display? After all the 15,6" screen consumes around 5 watts of power at 12 volt, so at 5 volt it should need 1A of current.

I would not want any additional input lag, so the VGA mod will be my choice then. I already checked out the guide, but the solder points sure are tiny! I guess the h and w sync signals can't be accessed from anywhere else, right?
 
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Stitches

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Thank you Stitches for your fast reply! Does that mean I can simply attach a 16.8v battery pack to the external DC input of the console? That would be really convenient! The display driver runs at 12 volt, I can't really tell if it's able to run safely with more voltage. The 5v mod sounds interesting, but will the internal 5v regulator of the switch be powerful enough to actually drive the display? After all the 15,6" screen consumes around 5 watts of power at 12 volt, so at 5 volt it should need 1A of current.

I would not want any additional input lag, so the VGA mod will be my choice then. I already checked out the guide, but the solder points sure are tiny! I guess the h and w sync signals can't be accessed from anywhere else, right?
Yeah you just hook up the 16.8v pack straight to the 12v power connector pins. There's a reg between those pins and the other regs to stablize the line, so you have to desolder the connector and run the wires there. I don't know how much current the 5V reg can output, but afaik all the stock regs are identical, just the output voltages differ. The 1.15v line chews nearly 2A of current, so it's probable that the 5v reg has enough juice to run the screen. All it normally powers is the USB ports and controller rumble, and that's fuckall really.

For VGA, yeah unfortunately the two pins on the AVE are the only locations to get the sync lines. Nintendo didn't intend for production models to use VGA, so they were left NC. With some magnet wire, flux, and a bit of patience I'm sure you can do it.
 

Kadano

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Those cheap Wii to HDMI adapters are actually lagless. I measured Wii Y signal vs G output (of Wii HDMI → HDMI to VGA adapter) and found a delay of about 3 µs, which is 0.003 ms and completely irrelevant. See below, first picture is a few single frames of white horizontal lines that flash up for five times (with pure black before and after). Second picture is the same but zoomed in enough that you can actually see the delay.
Wii Y vs Ali WiiHDMI plus Vention HDMI VGA RGBHV G output.png
Wii Y vs Ali WiiHDMI plus Vention HDMI VGA RGBHV G output 10us_cr.png

You can still do the VGA mod for internal wiring, which is what I did on my semi-portablized Wiis. But if the saved space for the external Wii2HDMI adapter is not important to you, there's no problem with skipping that part.
 
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Those cheap Wii to HDMI adapters are actually lagless. I measured Wii Y signal vs G output (of Wii HDMI → HDMI to VGA adapter) and found a delay of about 3 µs, which is 0.003 ms and completely irrelevant. See below, first picture is a few single frames of white horizontal lines that flash up for five times (with pure black before and after). Second picture is the same but zoomed in enough that you can actually see the delay.

You can still do the VGA mod for internal wiring, which is what I did on my semi-portablized Wiis. But if the saved space for the external Wii2HDMI adapter is not important to you, there's no problem with skipping that part.
Very interesting, thanks for the input! I wonder how the picture quality of the wii is with the VGA mod on my 768p screen in comparison to HDMI. I'll give the VGA mod a try first, considering I don't have to buy something.
 

Stitches

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Those cheap Wii to HDMI adapters are actually lagless. I measured Wii Y signal vs G output (of Wii HDMI → HDMI to VGA adapter) and found a delay of about 3 µs, which is 0.003 ms and completely irrelevant. See below, first picture is a few single frames of white horizontal lines that flash up for five times (with pure black before and after). Second picture is the same but zoomed in enough that you can actually see the delay.
View attachment 11752
View attachment 11753

You can still do the VGA mod for internal wiring, which is what I did on my semi-portablized Wiis. But if the saved space for the external Wii2HDMI adapter is not important to you, there's no problem with skipping that part.
I want to know what magical adapter you tested. All the ones I've used added an extra 2 frames of latency. And as if you've got two adapters in series with that latency.
 
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Hey guys, I was wondering if it is possible to increase the hole diameter of the four holes around the CPU, were the original cooler gets attached. Would it be possible to drill them out with a 3mm bit, or are there traces that can be damaged?
 

Wesk

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Hey guys, I was wondering if it is possible to increase the hole diameter of the four holes around the CPU, were the original cooler gets attached. Would it be possible to drill them out with a 3mm bit, or are there traces that can be damaged?
You can drill them out to basically where the gold area finishes without issue.
 

Stitches

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Just remember to tape over the CPU and GPU as if you were trimming the board. Don't want metal shards getting underneath and shorting the pins.
 
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Thanks, that's convenient! I reconsidered my ideas and now I actually do want to integrate a controller into the design, to be able to play wii titles like xenoblade chronicles. These games can be played with the classic controller, but the problem is that I can't hook it directly to the wii up. Do the built in controllers from all these portables here only work with gamecube titles? Or is it possible, to use them with native wii games?
 

GingerOfOz

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Check out this hack: https://bitbuilt.net/forums/index.php?threads/gc2wiimote-beta.2945/

I've played a bit of Xenoblade with it and it seems to work fine. You'll need to set up a nunchuk configuration, the classic controller hasn't been implemented yet, though it will be supported in the future.
Oh wow, this community really got everything, thanks for the link! I got an aftermarket Gamecube controller here that I can hack up for this. Really neat I don't have to buy anything extra :D
 

Kadano

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I want to know what magical adapter you tested. All the ones I've used added an extra 2 frames of latency. And as if you've got two adapters in series with that latency.
It was this one:
Wii HDMI.jpg


I did measure it exactly like shown, both adapters in series. I have a Wii that I've been using for lag measurements since ~2016, for which I've soldered wires for Y and ground to the respective multi AV pins so I can easily connect the Wii side of the video signal chain to my oscilloscope.

In this case I simply inserted male to male jumper wires into the VGA adapter's G and ground pins and hooked these to a separate probe of the oscilloscope, which is how I got the measurements I posted before.

I don't see any potential for error in this testing method. Total latency is 0.003 ms, so this Wii2HDMI adapter can't have more lag than that.

These are the very cheap adapters with "FullHD 1080P" printed text that only have the multi AV plug on one end and HDMI + 3.5mm stereo on the other end. No switch or anything, and contrary to their print, they only output 480p, never more than that.

On the 2-3 units I've used so far, colors are fine. The picture is a bit more fuzzy than other 480p options but it's quite negligible if you ask me.

See below for a comparison of that Wii HDMI adapter vs GC VGA (using a modified original Gamecube D-Terminal cable). I took them with a StarTech PEXHDCAP capture card set to the "shrink" color depth option (which gives the strongest effective contrast with that card).

Wii HDMI is a little bit darker, and in the details it's slightly less sharp, but the differences are honestly so minimal even when zooming in on the screenshots that I don't think the Wii HDMI adapters can be called "bad".
2021-06-21_154620.jpg


I've read people complain about their colors and sharpness, so I guess it's possible that the quality control is not great and a percentage of the units don't perform as well as the ones I've been using.
Regardless, at their low price (currently around 3 USD), buying 3-4 of them and hoping at least one is okay is still not that much of an investment.
 
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Shank

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I can vouch for what @Kadano has said. I've tested converters like this using a time sleuth and there are converters that are indeed (for all intents and purposes) lag free.

Analog to digital and digital to analog conversion can be lag free, and it normally is lag free in most situations. Latency can only really be added if the conversion device has a framebuffer. Framebuffers increase the cost of the converter, so they are often omitted on inexpensive converters. Old Wii2HDMIs from the early 2010s were completely different circuits than the ones sold today; I believe they even had scaling to 720p/1080p, which was likely the culprit. The newer ones have much cheaper, simpler circuits that do not scale.

The idea that ALL video ADC and DAC conversions cause latency is a myth, and it's a myth I personally have been guilty of perpetuating in the past.
 

Stitches

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I can vouch for what @Kadano has said. I've tested converters like this using a time sleuth and there are converters that are indeed (for all intents and purposes) lag free.

Analog to digital and digital to analog conversion can be lag free, and it normally is lag free in most situations. Latency can only really be added if the conversion device has a framebuffer. Framebuffers increase the cost of the converter, so they are often omitted on inexpensive converters. Old Wii2HDMIs from the early 2010s were completely different circuits than the ones sold today; I believe they even had scaling to 720p/1080p, which was likely the culprit. The newer ones have much cheaper, simpler circuits that do not scale.

The idea that ALL video ADC and DAC conversions cause latency is a myth, and it's a myth I personally have been guilty of perpetuating in the past.
I am learned today
 
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