Arduino-based flow meter we've built based on this open source design.
Parts cost is roughly $75. Compare that with at least $600 for similar commercial models. And this one can be built from easily available parts by students, and could be used to record data and even control the pump to produce hydrographs.
We're very excited about going open source, providing designs and parts for instrumentation to augment our Emriver models. If we get the NSF and EPA grants we've applied for, we'll also develop curriculum and supplementary video/visualizations. These we'll just give away. We like giving things away; you won't see our business model featured in Fortune anytime soon.
Not everything can be open source, do-it-yourself. Scientists don't build their own microscopes, laptops, or rock hammers because it's not practical.
We'll continue to do the hard stuff, like obtaining plastic media with tight specs (in both size distribution and color, from recycled materials, not easy), making the near perfect but hard-to-build aluminum box the Em2 uses, something I spent years on and am still refining. And as always, we'll push ahead with innovation.