@jackal123uk Thanks for sharing your solution! Mouseberryes are out-of-stock for a while and I would like to use this concept to power RPi from the car battery. When the engine is turned on, one of the 12V battery outputs is active while the other battery output is always 12Vs, so the goal is to transform 12V to 5V only if engine is on, to power RPi. I wouldneed such circuit to safely power off RPi when engine is turned off.

As I have really limited experiences with hardware, I would like to ask you how to modify the scheme to support such solution? Why do you have this USB in your circuit? Thanks a lot!

I've been meaning to provide an update for the for a while so here goes.

I still haven't fully resolved the issues with the controllers but I've not really had a good stab at it yet.

A few more photos; generally I'm happy. When reassembled the fan blows straight across the compute module (which was the idea) so adding a heat sink so keep it nice and cool.
IMG_6606.jpg

The HDMI port in not fully aligned - not a major problem but the perfectionist in me doesn't like it - that on the list of changes if there's ever a next version. Also, I'm not too keen on the empty hole to the right, might be an idea to add another USB port in future.
IMG_6607.jpg

Front USB port fits nicely into a slightly modified memory card port but doesn't sit at the correct height - something else to be tweaked.
IMG_6616.jpg
IMG_6612.jpg

As for the next version, this is on hold for now. One of the original aims for using the Compute Module was future upgradability base on the assumption future Compute Modules would keep the same interface/footprint. The ultimate hope was the come CM4 or CM5 the power might be there for GameCube emulation.

However, I've read that future versions might deviate from the SO-DIMM 200 interface, hence I'll hold off on making any more hardware changes with this until there's more clarity on what the future holds. It's been a fun process and has taught me a lot on the way - which was the real aim anyway!

@victimrlsh

Very nice! We have a Dave & Buster's around here, but I wish there was something more like that. Barcades are really growing in popularity, so I remain hopeful.

I think the first step would be to test if I can capture audio natively before I pass it through to GPIO.

I've narrowed it down to wanting to use the alsa sound driver. I want to be able to hear the sound from my speakers while it's being captured which is looking like I'll need to use a loopback device. Eg snd-aloop

I'll update this post when I have more details but I've gotten so far as sorting dependencies and just need the proper configs for /etc/.asound.conf

@azamoth
As @caver01 told you there are several ways... and your display just needs a few Pins as told....

If nothing else helps use MCP23008 or MCP23017 gpio expanders and connect to I2C-bus. But please don't ask me how to do this. Never used that :)

@martinrdgz i don't believe there's any rules/consistency about how game data is split across chips. also see http://wiki.mamedev.org/index.php/Dumping_roms

@Jiehfeng Just tried with another button, works fine. I guess that button was faulty. Thanks again. :)

@obsidianspider hahaha in not sure on that one. They are a shade more complex! Would be nice though