Easiest way for non-EEs is, probably, this.

I guess I meant the cheapest...

That looks awesome!

I was totally just wondering if something like this were possible on the SNES - whady'a think?

they are on the way, so i can't test just yet, but if anyone has one already and cares to check, that'd be a way to do this on your GG instead of SMS...  without the other bits.

this is verrrrry oool by the way.  simple but perfect is oh so many ways, and with a sample-importing guide now!  can't beat that...

The easiest way would be to make an EPROM SEGA Master System cart, and then use that with a Game Gear.

You need: EPROM programmer, a 32KB EPROM, a 32KB cart (World Prix, for example), a Master Gear converter and of course a Game Gear

TRG for SEGA Master System / SEGA Game Gear is a simple tool for triggering audio samples in real time using the control pad. Works in an emulator and on hardware. A tutorial on how to insert your own samples into the software is coming soon.

Features:
- 32 percussion samples split into 8 banks
- Variable playback rate / pitch
- Colourful visualisation

Controls:
- Directional pad up / down / left / right: trigger a sample
- Button 1 and directional pad up / down: change playback rate
- Button 1 and directional pad left / right: change sample bank

Credits:
- Thanks to Maxim for his Hello World tutorial / source code, which can be found here: http://www.smspower.org/maxim/HowToProgram

Download:
- ROM: http://milkcrate.com.au/_other/chipmusi … 110502.sms
- Source Code: http://milkcrate.com.au/_other/chipmusi … 110502.asm

Useful Things:
- How To: Import Samples into TRG: http://little-scale.blogspot.com/2011/0 … -into.html
- How To: Make a 32KB SEGA Cart: http://little-scale.blogspot.com/2008/0 … ystem.html
- MSEverdrive Flash Cart: http://krikzz.com/mseverdrive.html