The electronics of the Armadillo and of the Platypus will happily supply 1A of power per port for sustained periods (all pins combined!). A special controller can be ordered with 2A at one (or several) ports for a small cost. Higher currents will overheat the controller and permanent damage can occur. It will, however, supply higher currents for short periods of time, thus the implementation of the sPWM.
This program has been developed with the DIY, electronics knowledgeable people in mind, but of course we'll provide free advice if you are not sure how to implement it. We are also offering to make custom boxes to connect to the controller to interface it with any device of your choice (up to 4 per port).
Last - if you'll be operating a relay, do not use it to power on or off AC devices, restrain to DC, low voltage ones. If you need to control AC devices you should go to a purpose made device, heavily noise (and electrically) isolated to avoid potentially dangerous issues, such as our Dragonfly observatory control box.