Working with Andrea, a grad student in the Calve lab at BME, over several interactive design sessions we built this. The original requirement was "Place a force equivalent of 1-4 grams onto embryonic collagen and image it in a fluorescence microscope to provide a three dimensional image of its response to the force over time (It should organize and we'd like to see how that order originates) Things naturally started complex, stepper motors, flexures, force sensors for feedback etc. 

We ended up with a ebay bought, $30 record player tone arm. It has a built in 1-4 gram adjustable weight in the back originally to set the needle tracking force. A teflon pad in the front is at a slight angle to apply the force normal to the optical plane of the scope. Seems like cheating. 

A lab I support in Aero Astro needed a way to drop a single drop of oxidizer onto a test watch glass with drop of fuel in it. They record the reaction with a high speed camera. The challenge here is that the oxidizer is; corrosive, toxic, explosive and boils at room temperature. Working with the Purdue chemistry glass blower (Thank you Bob Gorman) this device was designed and made. The teflon rod in the center releases a single drop of the condensed liquid from the very bottom by turning the knob at the top, the whole device is water jacketed for cooling and safety. The apparatus was successful on its first deployment and has allowed the lab to take data previously unavailable. Its compact combination of continuous addition funnel and condenser.