Sweet! Happy Sequencing!

Ok, I measured and swapped the bottom left and top middle pins of the GB cable and also figured that I did something wrong with me MIDI Out port (also swapped).

The schematic shows, in fact, the gameboy-end side of the cable.

Since it's my little monster, I may scream: IT LIIIIVES !!!! GWAHAHA!

Thank you very much, shizcake!

Yes, that's the schematic I'm working from. Thanks for the hint! I will post my results later.

in case you're working from this schematic:

if i remember correctly, the piece of link cable that is shown represents a cable that is cut up and soldered to the arduino.
When you check the link cable with a multimeter, you'll find out that there are two leads that are crossed over in the cable, so the pinout is different when you use a link port and plug a cable into it.
I think it's the bottom left and the top middle ones, but i'm not sure. Try to swap these two.
i can check if you need.

I've had the same problem every time I've tried to use MIDI out with LSDJ and an AB... Haven't messed with the new LSDJ version, but I've built tons of AB's in the past and couldn't ever get MIDI out functioning. The way I usually test if the MIDI out jacks are working is by testing the MIDI thru functionality. If you can send MIDI thru, then your AB/MidiOut is fine and it's a problem with LSDJ. I believe the problem with mine is that I use a Mac and USB Smart Carts, which do not work well together, and it's corrupted my LSDJ roms.

Thanks for the replies.
Of course I set the sync mode to Midi Out. Ardiunoboy software is 1.2.3 (the newest one, I think)

My circuit is a little bit like Frankenstein's monster because I wanted to test everything before thinking about how to put everything inside a box, so I hope the annotations are helpful. There are no short circuits or loose connections. I tried to change the sides of the pins of the MIDI ports - I have no clue which way they have to go (the schematic is not very good at describing the MIDI pins).

Overview:

I guess you can't see very much here, but I uploaded it just for a overview of that beauty.

GB cable:

This is a part of the four-player-link-adapter thing. It was too hard to desolder it so I destroyed the PCB. The pins on the top layer are those of the flat side, the pins on the bottom are those of the shaped side of the plug.

Midi-In:

Midi-Out:

The 2K Ohm resistor that goes to the GND pin of the MIDI-Out is the pulldown resistor of the button. The 220 Ohm resistor goes to +5V.

Also, if I'm not mistaken, midiout wasn't implemented until version 1.2.0 of the arduinoboy code.

Obvious question: Did you set the sync mode in LSDJ to MIDI OUT?

Maybe post a picture of your circuit, I know the arduinoboy page has a mistake/is confusing about the pinout on the midi outand has some cables swapped, which led to problems with the scienceguy run... not sure if that was ever fixed.

Hey guys, nice to meet you.

I wanted to try out the MIDI-out function of LSDJ 4.7.3 (arduinoboy version) and built an Arduinoboy (using an Arduino Uno SMD Edition) so that I can hook it up to a SammichSID and a Korg Electribe.
The probem is: I don't get any MIDI signals.
I have checked the pinouts of the MIDI socket and the GB cable and LSDJ is playing some notes with Q commands.
Do you have an idea what I could possibly have done wrong? Or some common mistakes that I may have overseen?
As I don't need the MIDI-in I left that whole part away from the build (i.e. pins RX and 4 are not used) - could that be a problem?

Thank you very much.
Fabian

//edit:
I added the MIDI-in so that I can look if I can connect via MAX. The Midi-in seems to work (as the status LED is flashing when I try to connect). But for whatever reason there is still nothing coming from the Midi-out