Wild openQCM
Astrophysistis from Novaetech S.r.l. made open hardware a quartz crystal microbalance - http://openqcm.com/
"QCM could be used as a tunable gas sensor and for monitoring the aerosol deposition in ambient conditions. The applications in liquid environment show enormous potentiality. QCM is very effective in measuring binding events on functionalized surface, such as antigen-antibody binding and protein-protein interactions. It is a powerful tool in life sciences, being able to sense DNA hybridization and specific drug compounds."
if you know how to make thin film deposition... (not part of the open project)
The website provides a download for the software, electronics and 3D printed parts as well as some information and nice pictures on the technology...
lets build one - see if I find all the materials needed in my lab or stores around the corner (highest level open hardware check).
The crutial part beeing the quartz crystal oscillator Ryan George contributed the perfect hack: "you could always take the crystal out of a timer..."
