I'm starting to think maybe it will (ever the optimist).... assuming it does I assume I can probably get 5v/GND from the cart pins if I want?

If it will fit then that is a much better idea I guess! I am not sure it will?

Wait what? Why wouldn't you just build it into the super gameboy at that point?

thanks - I did try the screen off, I'm not sure if it's just a rubbish cable as I only have one to test at the moment, but for some reason both MGB and Pushpin have the weird noise on more than one DMG (LSDJ doesn't though.) It's kinda minor in the grand scheme of gameboy noise, but noticeable when it's amplified and the problem is it's kinda rhythmic, but not in a good way!

the plan is to build it in the SFC (if it will fit), and have the leds and button and MIDI ports on the SFC shell and the link cable appearing out of the shell so it can be plugged into the SGB2 I have.

I realise it doesn't achieve MUCH advantage technically/may not be less noisy, but I just like the idea.
I've not actually checked whether a SGB2 actually sends power to the Arduinboy yet, which might be another issue.

Have you tried turning off the screen in mGB? I think it's like select + start + a + b. Significantly reduces the noise.

Also are you talking about putting an arduinoby in a super gameboy, or inside the SFC itself?

Point taken on the trouble, but it's not going to cost me anything extra really.
If the Arduinoboy won't fit then will have to do it externally, just feels neat to build it into the Sfc shell if I can. My current Arduinoboy sounds a little bit noisy with mgb/pushpin, like power is pulsing when I am sending Midi so was thinking about taking power from the SFC to see if it avoids this. Maybe it is more trouble than it's worth -  I'll see how noisy it is through a link cable first.

You're right it's all technically a bit unnecessary, but I thought it might be fun...

It's not really best practice, but arduinoboys are typically powered through the link port.

Why not use a SGB2 with an external arduinoboy? This sounds like a lot of extra trouble and expense for no real benefit.

Off the top of my head, the link cable does not connect through the edge connector of a super gameboy so you'll still need a cable coming out of the SFC and a supergameboy with a link port. Unless of course you're considering using the SFC simply for power to connect to an actual gameboy - but that just sounds silly; in which case you could just use any USB or 5v wall wart to power it.

if I am just being mad, please do let me know, but this seems like a worthwhile thing to do

maybe this should be on the "Handhelds" forum... but has anyone seen someone try this?

I am wondering if there's somewhere obvious and safe to get +5v from in the Super Famicom to power the Arduinoboy as I have a hunch that powering it through the link cable might be a source of noise...

Any experienced modders got an idea on this?

thanks!