I've searched on instructables, I can't find anything but arduinoboy related tutorials, not Teensy

And I've searched on Google too, but maybe I can't find the good keywords. (English is not my native language)

Yes, the Teensy is in the battery compartment.
Gameboy gets its power from the Teensy by USB.

I don't have the precise links anymore, I think most of them are on instructables.

Hey buddy, thank you for your answer!
If I understand correctly what you say, you placed the Teensy in the battery compartiment, correct? And both Teensy and GameBoy are powered by mini-usb, that's it?

And also, do you have a link to the tutorial you've followers?

I just finished one this week.
It has USBmidi via Teensy, backlight, inverted screen transparant Shell and 10 WS218 LEDs (Neopixels) built in.
You loose the battery compartment, but it is powered via USB.
Link port is removed and replaced by Mini-USB.

I don't have time to make a tutorial (nothing new either, followed existing tutorials), but I can make photos tomorrow.

It's been a few month now, and I've keep searching for integrated Arduinoboy (or Teensyboy) tutorials, but I think this is an empty box.

Even just tips about the placement of the components inside the case would be great.

I don't have any preference, but I know Arduino is only din-midi compatible (but you can add the PCB of one of those cheap din-to-usb cable, right?) and Teensy is well fitted for USB, is this correct?

Do you want din-midi or USB midi?

Hello everybody! It's been something like a month I'm interested in making an integrated midi interface for the GameBoy, I'm a sort of electronics (and art) entousihast, but I don't want to fail, not because I'm affraid, but, you know, because of budget. So I've watched a 'big' amount of (damn there are just a few) tutorials about making an arduinoboy, but I've never seen one about making an integrated arduinoboy. I know it's almost the same thing, but as I said, I can't waste my money. Can you, gentle people of the internet, help me? (I was thinking, just photos, of course with explainations, of an opened GameBoy with an integrated arduino/Teensy would be cool, because is it me or this is not frequent over the web?)