I couldn't find a source for these beaded cord sprockets. Roller blind mechanisms have them in, but not in an easily usable form. I made my own and had them printed through Shapeways
. John Abella has made a parametric sprocket
suitable for other bead spacings that can be 3d printed at home if you have access to something like a makerbot or a reprap.
Push-fit a sprocket onto the 5mm shaft of the motor.