Wiring

You need to connect the red and white wires (clock and data lines) to two separate ports. The short explanation is this reduces the amount of bit twiddling required when reading, resulting in pretty consistent reads on an 16MHz Arduino. The blog post has a longer explanation.

I used a breadboard for this, but you could also just solder an extra wire on.

• Red wire: PORTB0 (Pin 8 on Duemilanove) PORTC2 (Analogue Pin 2 on Duemilanove)
• White wire: PORTB1 (Pin 9 on Duemilanove) PORTC3 (Analogue Pin 3 on Duemilanove)
• Blue wire: +5V
• GND (unshielded): GND

Handy diagram:

Converting images

To display images using the vmu_image program, produce a 48x32 text file with 'x' where you want the set pixels to be. I use imagmagick and go through pgm using this pipeline, which is not pretty but works:

convert mypic.png pgm: |python3 pgmtotxt.py - >mypic.txt