DoubleFlush's hazardous adventures!

[DoubleFlush]

Hi!

Please forgive the flamboyant title.

A thorough introduction is in order, before i start throwing the silly questions about.
I am an engineer in the making, studying Informatics and Automation in Norway. Programming is my passion (profession-wise), and i aim to get a masters degree in that field once i am done with my bachelor's degree. I have little/no real experience with electronics (other than the odd dissassembly of a broken unit "to see how it works" as a youth), but i have a father who has dabbled in electronics, and i have a fierce curiosity and a strong will to learn.
Several times have i stumbled upon videos on raspberry pies used to emulate old-school games, and having grown up with a gameboy never out of arm's reach, the idea instantly caught my imagination. It was, however, not until i saw Wermy's thorough tutorials and wonderful end-results, and found out the scope of the community surrounding this phenom, that i decided i would try my hand at making something myself.

I then quickly reached a couple of conclusions; the first of which being that the finished product will (hopefully) be gifted to my sister, on her birthday (in May).

The rest of the conclusions require some back-story, that isn't entirely necessary to read, if you're of the impatient type (in which case i appologise for my already longwinded style of writing).

~Story-time warning~

When i was young (somewhere around 10, i believe) my parents took my sister and I on an amazing vacation through Turkey. We were trekking halfway through the country (which, i promise, is farther than you may think) by bus. It was a journey of round about two days of constant bus-riding. Hour upon dreary hour of blistering heat in an elongated tin can on wheels, packed to the brim of hairy, smelly, angry-looking people, who certainly did not enjoy children playing around on the bus.
My sister and i desperately needed a temporary escape. And while i had, just earlier the same year, broken my gameboy (in a manner which i cannot for the life of me remember), my sister had hers yet. She had been given her gameboy the previous summer, along with a Barbie game. It was the first console she had ever owned, and she treasured it. It was her pride. It was one of those light-blue semi-opaque GBAs. And being the sweet little sister she is, she let me get turns to play, when she had every right to deny me. And thus we passed the long hours.
It wasn't until a while after we had stepped off the bus that we realised the GBA was no longer with us. In the bustle of leaving the bus, I (being the last to play) had somehow left the GBA on the bus, along with the Barbie game, and the bootleg "LoZ: a link to the past" game we had bought in a back-alley of a tourist-trap of a town. And while i presume it made some turkish child quite happy, this was of no consolidation to my sister. She was devastated. As was i, being riddled with guilt. She eventually forgave me, however, kind as she is, and was later on given a bright pink DS with nitendogs, and all was forgotten. Almost.

~Story-time over~

Now, i've done some light research (emphasis on "light"), and i understand that most newbies such as I will most times be told to start out safe, with a GBZ project. And i understand why, the case invariably being larger, and thus more forgiving of the inevitable mistakes one makes as one learns. However, as i'm sure you understand, this is no real option to me. The only real option is to make a light blue, semi-opaque GBA. I understand this is far more difficult, and i am willing to face the consequences of this choice. I do not shy away from a challenge, and if the community here is as good as my first impression has led me to believe it is, i will do just fine.

Now, for a wish-list of features i want in the product:

-GBA form-factor
-Runs Retro-Pi
-Has additional X and Y buttons, to facilitate PsP games (most do not use the joystick (of which i have no plans to include))
-Runs off a rechargeable battery, charged by usb
-Easily accessible HDMI port (not a must)


As i am fresh off the boat here, i'm going to have to ask anyone and everyone: what components will i need?

i figure the first step in building this is knowing the components required, and then figure out how to put it all together.
input please!

[CaptainDurden]

look here:

http://www.sudomod.com/forum/viewtopic.php?f=13&t=1188

and here:

http://www.sudomod.com/forum/viewtopic.php?f=13&t=1235


your remark about x and y buttons for use in psp games is confusing, you will need them for basically everything post NES but will on the other hand most likely not be able to fit a pi3 inside a GBA shell which is the necessary hardware to even begin considering psp emulation.

apart from that this must be the sweetest reason to attempt a build i have ever heard... <3


edit: you should also look here , that should help a lot.

[DoubleFlush]

Ah, thanks a lot!

I've seen gamepieadvance's stuff, but I'm unsure of whether it's the road I should be taking (his pub's, that is) as x and y buttons are a must for me. Do you think his boards would accommodate for the additional buttons well, or would that be a massive hassle?

Also, about the psp emulation: it was merely a wish. I imagined it would be far fetched. However, you say fitting a pi 3 in such a case is "unlikely", which discourages me, but not entirely. Am I to believe that it is at all possible? I don't know much (and I'm not really in a position to do any real research), but is it perhaps the ethernet port that is the biggest size restriction? And if so, is it removable? Or should I rid myself of the notion altogether?

Thanks for bearing with my silly questions.

[CaptainDurden]

in order to fit the pi3 in an original gb people desolder the usb and Ethernet ports and chop off a piece of the pcb, that way it barely fits. I don't think the gba offers the space needed to attempt something similar and it also opens up a bunch of other cans of worms like power consumption and cpu cooling. you're new to all this, so you shouldn't bite off more than you can chew. start with a zero, put x any buttons on the back. keep upgrades and ideas for later builds when you know more about the subject.

[DoubleFlush]

Yeah, sounds good. Im not too bummed out about leaving psp emulation be. However, just to be clear, I can still fit x and y buttons?
Also, will the 5$ zero on adafruit do the trick?
Thanks a bunch for the help!

[CaptainDurden]

not only will it do the trick, it's most likely the only sbc you can fit in a gba.

yes x any are possible but since real estate on the front is sparse every build I've seen so far put them on the back underneath the shoulder buttons. read the threads I linked earlier.

[DoubleFlush]

Yeah, I read them. I read you loud and clear about the limited real estate, but I think that I will, if at all possible, go for a front mounted solution. I'm going to order that one as soon as possible. Any other components I should just as well go ahead and order?

[DoubleFlush]

Alright, so I've been doing some research. I appreciate being corrected here (as well as everywhere else). I definitely need to learn!

As we've established, I definitely need the pi zero. I'm getting the 5$ one. It's small, and will do what I want it to.

I also need a screen. The original screen in the gba was 2.9", and while there may be real estate to expand, that would require a different screen cover (which I wouldn't know how to acquire), or none (an idea of which I am not fond). Additionally, I don't know what screens are compatible. I understand that I need a board that acts as an intermediary between the zero and the screen. Is this correct? Like a video control board?
edit:
i believe this one will be the one i'm going to use.
https://www.alibaba.com/product-detail/ ... 0.0.KPvl9T

Additionally, I need a battery with a power boost board to enable recharging by USB. I don't want to risk using a Chinese battery, so I'm getting a 2000mA/h lipo battery with a compatible powerboost off adafruit. Unless otherwise told, I will assume that this will work.

Furthermore I am going to need an audio controller. I have no idea what to use here. I want stereo sound, unless this complicates things exponentially, in which case I can settle for mono.

Naturally, I will need something to handle hid interfacing. Is this what a teensy is for? I think I will follow in the steps of wermy's first(?) gbz on YouTube, and use an original gba pcb and tap into the lines for the buttons, and add x and y in the same fashion as he did, with wide copper tape(?). Whilst this is not a pretty job, I can't imagine any other solution I could manage outside etching my own board (which I have looked into. Might not be all that complicated after all. Come to think of it, etching a simple pcb might be the best solution for buttons). Input? (pun intended)

Furthermore I think I'll go for a simple sd card reader breakout board, for the roms and whatnot, rather than making a solution using a modded gba cartridge.

Do i really need a usb-hub kind of deal? Why do people include these in their GBZ?

Have I missed anything?

[DoubleFlush]

Talked to my dad today.

i'm going to go ahead and order a lot of the components. Also, we've sort of decided that we'll be etching a custom board for the buttons.

Progress! kind of.

[DoubleFlush]

I now understand that a teensy is a fully fledged controller in and of itself. do i need one, in addition to the pi zero?

if not, what will i use to interface the hid?

edit: some light research reveals the teensy's hid listen program, which leads me to believe it, if nothing else, can be used for the aforementioned purpose, but i have yet to discover wether or not this is the most common, or even wise, path.