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Recommend me smallest possible parts

Posted: Thu May 11, 2017 4:17 pm
by Jack Schitt
Hello there. I'm doing a GBZ inside a GBA SP (thanks Wermy for inspiring me to do this!)

Obviously, space is an issue. There's even less space than I anticipated at first. So, what hubs, sound cards, microcontrollers, etc. have you used that might fit in here?

I (and probably anyone attempting this in future) would really appreciate it.

Cheers.

Re: Recommend me smallest possible parts

Posted: Thu May 11, 2017 5:24 pm
by Helder
I think @moosepr mentioned this in another thread somewhere about the dimensions of the whole case and possible parts that *might* fit. The pi can't be up where the screen is since it has little space there to fit anything thick so it's likely going to have to be some SPI screen with a ribbon or wire install to some extender board and have everything on the bottom part of the case.

Without custom parts or some creative dremeling of off the shelf parts it's going to be tough, and what about a battery to power this thing?

Re: Recommend me smallest possible parts

Posted: Thu May 11, 2017 5:57 pm
by Jack Schitt
Thanks for the reply.

If I'm lucky, the Pi might fit there. I'll gain a few millimetres later by using something else than thick double sided tape and by possibly desoldering the HDMI and USB ports. I can also move it to the very edge. I just hope that the generic BW-like screen I ordered has a small driver board. If all that fails, I'll cut the bezel a bit to mount the panel further away.

For battery, I'll try something small that'd fit the original battery compartment, even if I have to sacrifice battery life.

Luckily I have experience with "creative" dremeling.

Re: Recommend me smallest possible parts

Posted: Thu May 11, 2017 6:50 pm
by ICMF
I wonder if it would work better if you approached it more like a 'Minty Pi' than a GBZ. After all, an Altoids tin is smaller than a GBA SP. So, lose the USB hub, go with GPIO controls and just do a simplified, stripped down build.

Re: Recommend me smallest possible parts

Posted: Thu May 11, 2017 7:41 pm
by RetroRocket
Jack Schitt wrote:
Thu May 11, 2017 5:57 pm
Thanks for the reply.

If I'm lucky, the Pi might fit there. I'll gain a few millimetres later by using something else than thick double sided tape and by possibly desoldering the HDMI and USB ports. I can also move it to the very edge. I just hope that the generic BW-like screen I ordered has a small driver board. If all that fails, I'll cut the bezel a bit to mount the panel further away.

For battery, I'll try something small that'd fit the original battery compartment, even if I have to sacrifice battery life.

Luckily I have experience with "creative" dremeling.
If you can get it to work, you might want to look into stock DS Lite batteries, they're pretty small. How much of the structural support can you reasonably remove...maybe just leave three mounting bosses for each side?
You may have to DIY some of the components like amp/buffer etc into custom shapes to Tetris into each other. I doubt you'll be able to 'layer' much of anything, so having everything on one plane would probably be the most efficient.

Edit: I'm sure you're also going to use the GBA cart reader space, so maybe the first port of call is to epoxy in a sacrificial cart, then cut out all those walls on the inside for maximum space.

I would draw out a profile of each component you need and the internal dimensions of the case, then tangram it up until it fits!
Love the challenge though, and double love for the NES themed case :D

Re: Recommend me smallest possible parts

Posted: Fri May 12, 2017 2:11 am
by moosepr
just my cuppa tea :P

if you go for the ili9341 screen from the minty pi rather than the backup camera screen, you will have more success. You may need to transfer the screen onto a smaller pcb though, the standard ones stick the connectors at the end so its harder to get it to fit.

pi in the bottom will be easier, you then have to run the 8 cables up to the screen, but you can keep that intact.

i agree with @ICMF, ditch the hub, go GPIO for the buttons, that will save you space and power, then you could probably squeeze an I2S board in there for the sound. (https://www.adafruit.com/product/3006)

ditch the powerboost, just get a tiny charge protect board, the pi and the screen will run as low as 3v happily. With a tft, pi, gpio buttons, you should get 4 hours from a 1000 mah battery which you will have space for. the adafruit I2S board will probably reduce that, i have never tried one yet, so i cant comment

good luck :)

Re: Recommend me smallest possible parts

Posted: Fri May 12, 2017 8:38 am
by Jack Schitt
@ICMF
Good point. I might just do it that way.

@RetroRocket
I have (or had) a DS Lite. I recently found it's charger so the DS might still be around somewhere. I'll check that out.
There's a lot of wasted space to gain from the internal supports, especially on the bottom part.
And yeah, I'll use the cartidge space. But if I can, I'll put some of the components in a cartridge and use a DS GBA connector for the sake of coolness and stupidity.

@moosepr
I'll keep that in mind, but will try the backup screen first, as it's already on it's way.
The I2S seems good - I think that I'll be able reduce it's footprint to make it even smaller. I'll order a couple.

I'll see how the backup cam screen turns out and if I can keep the Pi up there

Edit:
Can I get stereo for headphones from the Adafruit I2S?

Re: Recommend me smallest possible parts

Posted: Mon May 15, 2017 6:53 am
by Jack Schitt
I have extremwly good news. The BW screen just arrived. While it took some precision dremel- and knifework, the panel is an exact fit. Even better, the board will fit on the lid if I solder off the caps, etc. and do extension cables for them to somewhere more spacios place like the edges.

Then, some less good news - the board seems to be a yet unknown variant (I'll give a high res image when I get to my DSLR) and my only available micro SD card died so I can't test the screen.

Re: Recommend me smallest possible parts

Posted: Sat May 27, 2017 1:38 pm
by codeman0624
Jack Schitt wrote:
Mon May 15, 2017 6:53 am
I have extremwly good news. The BW screen just arrived. While it took some precision dremel- and knifework, the panel is an exact fit. Even better, the board will fit on the lid if I solder off the caps, etc. and do extension cables for them to somewhere more spacios place like the edges.

Then, some less good news - the board seems to be a yet unknown variant (I'll give a high res image when I get to my DSLR) and my only available micro SD card died so I can't test the screen.

Looks good! I've been thinking of attempting this as well. I'm just starting building a parts list. Where did you buy that screen?