Pi in a Gameboy Advance Build - WIP

moosepr

@obsidianspider the adafruit i2s board is tiny, and only needs 3 gpio pins https://learn.adafruit.com/adafruit-max98357-i2s-class-d-mono-amp/raspberry-pi-usage

The only problem might be that it will need to use pin 18, which is normally used by TFT screens for backlight (as it can do the pwm that is handy for the sound part)

obsidianspider

@moosepr It looks like the I2S isn't going to work because on my screen pin 19 is being used by the screen.

thedudester80

@obsidianspider You could use a composite display. That way the GPIO is open and the I2S is available.

obsidianspider

This ABXY thing is kicking my butt. With that trigger button where it is, there's no good way to put X and Y buttons on top of the existing B and A holes.

I'm thinking way outside the box here, but the New 3DS has ABXY , and you can get replacement buttons for ~$9. Not super cheap, but they're the colors I want and would be cheaper than buying a bunch of gameboy pocket buttons that wouldn't all fit anyway. And…

They're smaller.

Using some overall dimensions I saw online and doing some guesswork, it looks like the ABXY cross is ~24.5mm across. I don't have a New 3DS, but I might be able to go measure one at a store display since they are still the current model.

So what if I drill a 1" (25.4mm) hole in the front of the Gameboy, then 3D print a button panel to fit that hole. Kind of like how there's a circle on the face of a Super Nintendo controller…

It'd kind of look like this…

This assumes the ABXY buttons are the size I think they are.

I have a feeling I'm not going to be able to pull this off. :-/

moosepr

@obsidianspider you could glue in the insert, fill the gaps with a filler of your choice, sand it smooth then give the whole thing a coat of paint.

That's how things like this are born http://modretro.com/xen/index.php?threads/gamecube-portable-the-varia-cube.15084/

moosepr

@obsidianspider actually this one is exactly what you were planning http://modretro.com/xen/index.php?threads/game-gear-x-brasil.15052/

I did ponder the same with an old broken nds for the buttons. Even got a red one so the red buttons would look good against the white GBA

obsidianspider

@moosepr I just fell into a frankencasing rabbit hole. This looks pretty doable. I just don't know how I'm going to blend the textures together…

obsidianspider

I decided to buy a broken DS Lite from eBay for $7 to see if/what I can do with the buttons, pads, and case. Should be here next week.

moosepr

@obsidianspider I did also fall into a googling frenzy for the second time. I always have these ideas, then research the hell out of them, then never find the time to actually finish (or in this case, even start them!)

This guide seems helpful http://bitfixgaming.boards.net/thread/138/frankencasing-controller-parts-case

obsidianspider

I decided to try out the "use GPIO as a controller" thing today and I used test leads to make my "buttons"

Then I connected them up to the GPIO using the pin numbers from the Adafruit PiGRRL 2 Default Controls. I may change this to tidy things up in the case, but this was just a test.

I then installed the retrogame software and configured it by commenting out the buttons in the config file I wouldn't be using.

When I rebooted the Pi to try to configure things my screen started acting wavy and I thought that there was an issue with conflicting pins, but it turned out that my very quick mockup had some screen wires touching each other and that was causing the disruption.

Mapping the buttons was just like any other controller in EmulationStation and things seem to work fine.

If you're finding the MAME ROW too easy, you can try this new controller out. ;)

moosepr

@obsidianspider thats one less usb required ;)

obsidianspider

@moosepr said in Pi in a Gameboy Advance Build:

@obsidianspider thats one less usb required ;)

Haha, yeah, 13 wires to replace 4…

At some point I still have to figure out the power situation to see if I have enough GPIO pins available.

cyperghost

@obsidianspider Can you please provide a better resolution of your latest photo?

As you don't use the Key buttons of your screen GPIOs are set free
Can you recheck your wiring with this picture by adafruit please?

or can you recheck if you have GPIO 18, 40 or 45 free? These pins can provide PWM sound! I think you don't need a USB hub :)

moosepr

@obsidianspider there are ways to reduce the number of pins your using http://raspberrypi.stackexchange.com/questions/14035/8x8-matrix-of-buttons but it does mean you will need different software to scan the rows and columns to figure out what is pressed

obsidianspider

@cyperghost Sorry for the delay, I was helping to run Bacon Fest all day today, and I'll be back tomorrow.

That's ~1/5 of the festival area. A few people showed up. ;)

This is my current GPIO setup (I have been writing it on a diagram as I go through wiring it up on my Pi 2 test machine)

I know you REALLY want me to use that I2S amp, but from what I can see, it's mono, and I want stereo sound to the headphone jack, so I don't know that it would work for me, plus I'm already running out of GPIO pins, and I still need some for my power switch once I figure that out. Even my Mausberry needed at least two when I did that on my Super Famicom.

Semi-related: I got Pi-related mail today.

Can you guess what was in the box and what was in the padded envelope?

If you guessed that the box was for the 24mm Adafruit amp and that the padded envelope was for the Pi 3, you'd be right. Haha. I will never understand shipping decisions. For what it's worth, they were ordered from the same company. The Pi 3 was a free giveaway by Arrow this past week. Now I have to make something cool with that too…

obsidianspider

@moosepr I'm not sure I need to go the multiplexing route, but if I run out of pins, I'll keep it in mind. I haven't really researched how to do that at all and my brain is fried from doing volunteer work for 12 hours, and I'm doing more tomorrow.

moosepr

@obsidianspider fried! Bacon! I'm intrigued, was it a massive festival devoted to bacon?

obsidianspider

@moosepr Haha, I totally missed the "fried" and "bacon" reference. I guess it depends on how you define "massive." They're expecting ~75,000 people to attend this year's Bacon Fest

moosepr

@obsidianspider awesome! The best we get here is beer festivals! I would love to go to a bacon festival!

cyperghost

I know you REALLY want me to use that I2S amp, but from what I can see, it's mono, and I want stereo sound to the headphone jack, so I don't know that it would work for

No I want to save you from using a USB HUB ;)
I see 2 issues:

the single OTG USB provides 500mA output - if you use a HUB (passive) then every connector provides just 100mA
space in your housing ;)

I don't know if you want a real handheld console. If yes you need space for batteries, charging balancers and switches.

I never said "I2S is the best f*ck the rest" - as related to my build I recommended sound via HDMI or USB sound card. But in my build there was no additional space for an extra Hub. So I tried PWM sound that didn't satisfy me and then switched to I2S which was my last resort and I benefit from a devices that mixed left+right audio channel into mono speaker. I never demanded sound via headphones, so your solution seems best and you can argue with "real stereo".

Thank you very much for your diagramms. I also learn a lot of your builds and ideas. Have fun on your party.