Neat! Glad to hear you're into making your own electronics too.
I'll explain how to go about this and if you need more details I can send you photos or maybe some video.

You'll NEED a multimeter to do this!

FIRST
Take the cable I gave you and place both ends facing you. It'd be great if you had some helpy hands to hold it. Set your multimeter to the continuity check setting. This is the setting that beeps when both test leads are touching the same electrical path.

Place the first test lead (either hand) to the top right hand tooth of the DMG cable. With the other test lead move it between the points of the the MIDI Cable. When you hear a beep, that means that DMG tooth corresponds to that part of the MIDI cable. WRITE IT DOWN!

Do this for every tooth of the gameboy cable until all pins of the MIDI Jack are accounted for.

Note: The bottom center tooth of the DMG cable will have no connection. Also, when I say 'bottom' I mean the fatter side of the cable and 'top' relates to the side that is pinched a little bit

SECOND
I highly recommend buying a new male MIDI plug for this part rather than trying to modify the cable I gave you.

Take your GBA Link cable and cut it in half. You'll want to strip the series of wires in there so your multimeter will be able to make contact with them. Now, do the same thing as Part 1 except this time, you'll be taking note of the colored wires inside the GBA cable rather than MIDI Pins.

THIRD
Take the information you know from both experiments to find out which wire of your GBA cable should go to which pin of the MIDI plug.

This is a treacherous part as you'll constantly be trying to discern front from back of the MIDI plug.

TAKE YOUR TIME. Take good notes on colors and you won't have a problem at all.

When you're completely finish. CHECK YOUR WORK. Compare it to the cable I sold you and make sure that all the teeth correspond to the same MIDI pins.

For example, if the bottom left tooth of my DMG cable correspond to the middle pin of the MIDI plug, then yours should as well!

Hope this all makes sense to you?

BTW Hit me up on email for a faster response - byrnework@gmail.com. I check the forums every few days.

Ho, sorry,
I mean, I have a two midi plug :
- One plug is a midi in ;
- One plug is a midi to DMG port ;

Daily I use a gba sp, and I think I could easily build a "midi to gba sp cable".
I don't know the pin which are used from the cable.

Could you help me on this side.

One last thing, I think you have made one of the best arduinoboy i've see.
Thanks a lot

Hi just to tell you, I've plug on my DMG and it's fine.
Do you have a description or schema of the board ?
And cable ?
I will need to create midi DMG cable.

Thanks a lot

PLEASSE!!

Thank you

Ah.

The enclosure is just a simple stompbox case for guitar pedals. You can pick them up relatively cheaply.
http://www.mammothelectronics.com/4S125B-p/500-1002.htm

I wish I could die-cast aluminum enclosures!

I like the enclosure they are awesome, can't wait to receive this little beast !!!!
And thank you to make professional weapon

How did you make this enclosure ?
I'd like to know more people with this mechanical skills.

I'm interested in one.Would love to know when a new batch comes(cheaper ones)

DAAAAAAAAAAAAAMN

damn!

looking forward to the kits!

those enclosures were very classy

WOW! I was not expecting that. Thanks a bunch everyone! I'll be posting the PCB by the end of this month.

I'm still at work on putting out some cheap kits (~$35 for everything).

Hit me up if you're looking for something custom.

Got the last one!

Yes, the PCB I'm designing will function like a miniature swiss army knife. It'd be very easy depending on your needs to either utilize just MIDI In or MIDI Out ports, or both!

The PCB is actually small enough to fit in a DMG battery housing. If someone wanted to power the GB with a power supply, they could put the PCB right inside and hardwire it right into the GB. No external housing necessary.

I've also made it single sided, so that anyone looking to etch their own, won't have to pull their hair out trying to match sides.

The other MIDI port is for the GB link cable. I've made a note to design a more intuitive jack.

I've wired the cable and the circuit so that if the GB cable is linked to other port by accident the GB Power won't damage the circuit.

So, no worries!