9 October 2011

Building a Cube64... part 1

A few years ago I came across a nice project, it was an adapter for gamecube controllers on the n64.

I thought at the time it would be very cool to build one of these into an n64 controller plug, but it ended up in my "ideas i'll get round-to one day" pile and I never actually made anything of it.

Recently darthcloud added some new features to the code, so I decided I'd finally have a go at building one.

Fundamentally the hardware for the 'cube64dx' is simple, essentially it's just an 8 pin micro wired to the appropriate pins on each controller, all the clever stuff is done in software.

One nice feature is that it emulates the rumble pak using the gamecube controllers built-in motor. However this requires 5V which is not available from the n64 so we need to include a step-up converter for the rumble feature to work properly.
The original project spec'd a MAX682 charge-pump, but these are very expensive in small quantities so I looked for something cheaper and found the TPS60151 at a much more reasonable price.

The TPS60151 only came in a tiny 2x2mm 6SON package so I'd have to design a little pcb to build the circuit on.

To make my circuit board, I used the toner-transfer method, it's probably the simplest diy way to make pcbs and gives decent enough results.

The theory is, you use a laser printer to make a mirror-image of your circuit, since laser toner is a finely powdered plastic, you can re-melt it and it'll stick to copper-clad board.

The toner image then acts as an etch-resist. When you bathe the board in an etchant solution, the copper is dissolved in all the places that the toner didn't stick to.

You can get decent resolution with this method, and only need a few inexpensive tools/chemicals:
  • a laser printer (I picked mine up for free from an office clearance)
  • some glossy magazine paper
  • a clothes iron
  • copper-clad board and etchant (I use sodium persulphate because its translucent)
  • and goggles/gloves.

Making my board in this way only took about 15 minutes, mostly waiting for the copper to dissolve.
  • First I mirrored my design and printed it onto some glossy paper.
  • Then I scrubbed up some copper-clad board using steel wool and cleaned it off with acetone.
  • I heated the board to about 190°C using a clothes iron.
  • I carefully layed the printed paper onto the copper, covered it with a piece of clean paper and heated it again with the iron for around 10-15 seconds until the toner had stuck to the board.
  • After washing away the paper with cold water, the board was ready to etch.
I then soldered the components and tested out the prototype circuit, happily it all worked first time.
Now came the task of fitting it inside the controller plug and I'll cover that in another post...

3 comments:

  1. Just wondering if you ever completed this project, the follow up post would be great! I'm looking at making one of these (read that as four) myself to attach my wavebird controllers to my N64.

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