Earlier this Spring, we were contacted by Urs Gaudenz from GaudiLabs and he told us about a low-cost, DIY-friendly DMF platform he was developing along with collaborators from the Bioflux project, called the OpenDrop.
The OpenDrop is a fully integrated device that is not much bigger than an Arduino Uno. It does not require any external high-voltage amplifier and uses MosFET transistors to control the state of each electrode (instead of the more expensive PhotoMOS chips used in the DropBot). These modifications reduce the system cost considerably, from ~$5,000USD down to a couple of hundred dollars, a level where many more people (e.g., DIY hobbyists) would be willing to build one just to play around with, which we view as a very exciting development!
Urs graciously sent us an OpenDrop, and we just finished writing firmware and a plugin that allow it to be controlled from Microdrop. We’ve added instructions on the Microdrop wiki.
The OpenDrop uses DC electric fields instead of AC (a simplification that drives a lot of cost savings) and does not perform any impedance-based sensing. It also uses a PCB-based electrode array that is covered by a removable film (Saran wrap), instead of removable devices. While this certainly works for moving drops around in an open plate configuration, it is unlikely to work in the more useful two-plate configuration (necessary for dispensing and splitting) unless an oil-filler is used. That being said, we think it should be possible to achieve many of the cost savings while maintaining most of the added functionality of the DropBot system, which is the focus of our current development efforts. In any case, we see the OpenDrop as a very exciting development that will bring more people into the open-source DMF community.