We now have all the parts assembled and have started to find the height and distance determinations to get the best gradient. Below is the setup. The Air Brush is mounted on the Lego trolley which moves side-to-side on the metal bar track powered by the 3rd motor in the MindStorms kit. The substrate is held by a three position holder mounted on a hotplate allowing the substrate to be held at -60, 0, and +60 degrees. This assembly rides up and down on a three wheeled wood block that runs on the wooden board track with three grooves. The assembly is positioned with a lab jack and a ruler mounted on the wood track allows us to properly position the substrate in front of the air brush. The soda bottles on the sides collect the spray when the air brush is not over the substrate and allow the solutions to drain into beakers.