I think the best way would be to open-source an already made AT design (I remember that ITPRL had a design (http://www.fao.org/docrep/010/ah810e/AH810E00.htm#Contents ); perhaps WOT, Working Group on Development Techniques, University of Twente ) has some designs too. Finally, I think that it would also be useful to open-source a basic piston pump; already worked a little on this but stuck for the moment, see User talk:Chriswaterguy KVDP 08:28, 11 March 2010 (UTC)