Pi in a Gameboy Advance Build - WIP

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.

obsidianspider

@cyperghost I don't claim to know what I'm doing or how I'm going to get there, but my idea for sound was initially inspired by the NeoPiGamer. They didn't use a hub, but the lack of wifi is something I found really annoying when tweaking my Zero. Maybe once it's set up it won't be bad, but initially it was rough.

I'm not going to use the OTG connector for power, I'll be tapping right into the 5V power source that's feeding the Pi, so I won't be limited by the port. What the hub can handle outputting is another matter, but the one I picked up seems to work with wifi, a keyboard, a controller, and a USB sound card, simultaneously. I know I can do the controller via GPIO now, and I'm glad I tried it. I was intimidated by it before and now I see it wasn't bad at all.

Your I2S-ing has inspired me to look into building a Shairport Pi with an optical audio out. AirPlay to my home theater has been on my "to do" list for a while but I didn't want to buy an AirPort Express. A Pi solution will probably end up being more expensive, but I'll learn something and, knowing me, I'll find some way to incorporate a little scree into it.

I'm not sure how I'll do the hub yet either. I wish that one I bought initially wasn't a piece of junk as the board was a small square, not a spread out rectangle, but I think I might be able to fit it in the bottom of the case once I desolder the connectors.

cyperghost

@obsidianspider said in Pi in a Gameboy Advance Build:

... lack of wifi is something I found really annoying when tweaking my Zero. Maybe once it's set up it won't be bad, but initially it was rough.

Yes the missing build in WIFI of the Zero hurts bad. But for my own I use the WIFI just with a external hub for loading ROMs on it or to tweak the system. So a generell network link isn't needed. Of course a permanent solution is better :)

handle outputting is another matter, but the one I picked up seems to work with wifi, a keyboard, a controller, and a USB sound card, simultaneously.

That should work :) I used the same setup for testing purposes but there was rare space in my Pie housing. max height of each componet ist just 9mm ... enough for a USB-A connector :)

Your I2S-ing has inspired me to look into building a Shairport Pi with an optical audio out.

I think it's not a matter what is really the best. That depends strong on personal view point. About the sound topic - I made the experience that most people (even those on adafruit) were really satisfied with the PWM sound ... in the adafruit forum only one guy wrote, that the static sound, generated by the Pie, get him on his nervs. He was satisfied with the ingame sound, too - but if there is silende (because you are in the ES main menu or gamelist menu) you always hear pops and hisses ... So he builds a "mute function" via GPIO :)

I used I2S instead. But even this isn't perfect you always hear a "POP" if the amp gets activated. But it's nothing compared to PWM soundoutput.

To come to end ... take the time to experiment with different solutions and then select the best fittings.

I'm not sure how I'll do the hub yet either. I wish that one I bought initially wasn't a piece of junk as the board was a small square, not a spread out rectangle, but I think I might be able to fit it in the bottom of the case once I desolder the connectors.

For gods sake, desolder the connectors they need space :)

It is a real pleasure to see the energy, the ideas and the creativity in the development in all these builds ... mockups ... projects ... whatever they named :)
It doesn't matter if these were created from @adamspc @obsidianspider @Tekkaman_Slade @UDb23 @Thak @Zigurana @thedudester80 @monstermadeofman @stahl80 @raygan and all I've forgot.... All did do a great job: There was an idea, there is fun - let's build a case for emulation with the Pie

Btw: English is not my native language so please ask if I expressed something unclear, okay?

obsidianspider

@cyperghost your English is just fine. I only speak one language, so I would never criticize someone for not being perfect at English when they also know other languages. (I'm sure that even my English isn't completely correct at times.) I understood your comments and you have helped me quite a bit. I will be volunteering all day again today, so no Pi progress, but that's ok.

moosepr

@obsidianspider there are a few different i2s boards that are designed for stereo output, there is a little bit of a craze for making audio players from pi's. The apparently give good sound quality, but I have never listened to one so i can't comment.

The main problem is that they are not designed to be small, and are not really all that cheap either.

Most are designed for the larger pi's like this
http://www.iqaudio.co.uk/audio/8-pi-dac-0712411999650.html
Which would actually work with the zero, just not fit inside your case! There are smaller ones designed for the zero
https://shop.pimoroni.com/products/phat-dac
But again, that will make space an issue

There is also a plan c that I'm not sure if it will work. But looking at the tiny adafruit i2s doohickey, you can actually tweak the device to do just the left or just the right channels. Now I'm my limited understating of i2s is that it is quite one sided communication, so it may be possible to wire one in for each channel to get stereo sound.

I have had a thought though, how many of the games that can run on a zero, have actual stereo audio?

cyperghost

@moosepr said in Pi in a Gameboy Advance Build:

There is also a plan c that I'm not sure if it will work. But looking at the tiny adafruit i2s doohickey, you can actually tweak the device to do just the left or just the right channels. Now I'm my limited understating of i2s is that it is quite one sided communication, so it may be possible to wire one in for each channel to get stereo sound.

That's possible imho (I haven't tried) but the small adafruit amp is designed for seperate channel so using two of these should work. As I often said... These little boards may be a good choice for the Pi0. I think HDMI splitters are not cheap - also a good (and cheap) solution is use of a USB sound card (with the HUB thing).

But it's a manifest .... If you are in need for GPIO wiring to get sound then rather use I2S than PWM.

there are a few different i2s boards that are designed for stereo output, there is a little bit of a craze for making audio players from pi's. The apparently give good sound quality, but I have never listened to one so i can't comment.

Yes that's the point why I2S may net be used so often. Hifiberry and Phatdac are knowen solution but they are big in size and well... the costs are high. Of course they are designed for stereo output - the I2S system is common in every CD player. I also think they need a lot of more wires to work. Some use the I2C bus to get volume control. And some use I2S just as converter and need a separate AMP. So the little adafruit is just cool :) and the prizing is more than acceptable :)

I have had a thought though, how many of the games that can run on a zero, have actual stereo audio?

Some Mame games and some SNES games. Moreover PSX is very common and well N64 and PSP (but +Pi0=automaticfail). I think in 85% it doesn't matter if it's mono or stereo. But what I can say is that the adafruit I2S amp gots a excellent and powerfull sound output!

diegzumillo

Hey there
Just to add some more comments to my quoted comment up there. There was a topic at adafruit's forum where they explained their powerboost 1000's limitations. If I remember their words it was something like "the pi 2 is already stretching what the powerboost is capable of but it's not meant for pi 3". Those were not the exact words but the idea is that it actually works on the pi 2, if you need more performance than the pi zero. "Stretching" to me means it works.

cyperghost

@diegzumillo
Sorry, I didn't get you :D

obsidianspider

The broken DS Lite I bought on eBay showed up today.

Using two guides over at iFixit I had the DS Lite apart in minutes. If I was actually trying to put it back together again I could see it taking much longer.

I'm mainly concerned with the ABXY button area and that part of the circuit board, but I've read that the DS Lite speakers sound pretty good, so hopefully these aren't blown. It also had the 1000mAh 3.7V battery inside, so I may mess around with that a bit during my initial testing of going on battery power.

It looks like I'll be able to section out the ABXY area of the case and frankencase it into the GBA case

I took a piece of scrap paper and did a rubbing of the button holes from the DS Lite and placed it on the GBA case and it is like it was made for it.

Next I'm going to see if I can wire up the ABXY buttons from the DS Lite and the directional, L, R, Start, and Select buttons from the GBA. I found some pinouts on a few different websites.

0_1478728954020_dslight pinout.jpg

With how thin the DS casing is I'm thinking I will be able to put the DS Lite PCB on top of the GBA PCB and that extra depth should make up the difference in case thickness. At least that's the theory.

Onward.

moosepr

@obsidianspider looking good dude! I did think those nds buttons would be a good fit for the GBA