Microcantilever---direction of deflection I was reading a paper on a microcantilever-based hydrogen sensor. Here's how the sensor works (as I understand it): The cantilever is coated with Palladium film. In the presence of Palladium, diatomic hydrogen splits into H atoms, which are absorbed by the cantilever. The stress imposed by this absorbance bends the canitlever, which changes the capacitance. Thus, percent hydrogen is a function of capacitance. I would expect the deflection to be downward. However, the plots in the article show that the values for cantilever deflection (as measured by an optical sensor) are positive. For example, for 10% H2 concentration, the measured deflection is ~.4 micrometers. For 0.4% H2 concentration, the deflection is 1.2 micrometers. Can someone explain this behavior? The diagram in the article that shows how the device works has the cantilever bending downward (which I assume would be a negative value of deflection), but the plots show positive deflection values. Thanks for any help!