MIDI Interface for GameBoy:

Connecting Pushpin by www.DSPerado.com to your MIDI sequencer, keyboard and drum machine

To connect these two interfaces, first get a GB multilink cable (from Toys R Us - $9.95) and plug it in to your GB. Using pliers, pop open the clear, plastic junction box where the three cable ends meet. The wires are soldered together on a tiny breadboad. Turn Gameboy on and start pushpin. Using a Voltmeter, search for the +5V and Ground signals. if you see -5V, you have them reversed. BTW, make sure to do this while Pushpin is running (press Start), so that you don't get fooled into thinking the GB serial output is the power source.

Next, isolate the incoming MIDI signal with a 6n138 as per the MIDI for ez-kit lite schematic. Add a .01 uF capacitor across the power supply, and a 1K resistor from pin 7 of the 6n138 to ground (to increase the rise time!).

You can power the 6n138 using the +5V and Gnd from GameBoy. Begin sending midi data at a steady rate. Connect pin 6 of the 6n138 to one of the other wires on the gameboy connecter until you hear hear GB click to life. Then, solder that wire in place.

Construction Tips: drill tiny holes for the 3 wires in the clear, pastic junction box to come out, and click the lid back on.

Thanks to Emma's Pizza for making this stuff (and life) just a little bit more enjoyable.

Thanks to Brian Whitman for writing Pushpin's software, proving to the rest of the world and me it could really happen.

Thanks to Ron Ross for agility in analog circuitry in the MIDI Interface.