We're wrapping up the pumping part of our redesigned Em2. The new model will use electronics to control a 12-volt pump and send flow rate data to an LCD display (and also to a PC via USB and possibly wireless connections).
We're using an Arduino board as the brain for this; it'll be totally open source, understandable and hackable by users and students.
Today, after a few weeks of intense work, we got the final conceptual kinks ironed out, thanks to Chris Alix of Prairie City Computing, Chris Krumm of Tropo Studios, and others I can't mention.
Many thanks to them.
Immersed in electronics and the physics of pumps over the last few weeks, I've been floored by commonalities between fluid mechanics and electronics. Most geeks understand this, but what's exciting here is that we can use the controlling electronics for the Em2's pump to teach hydraulics and vice- versa.
Beyond comparing current and pressure in hydraulic/electronic circuits by way of analogy, we're building a system where they interact, with data collection for both!
Resistors are like riffles--converting flow into heat. A low pass filter in our circuit (a resistor-capacitor network) that smooths an electrical square wave is much like a pool. There are some very cool analogies with basic bedload transport process to explore.
Bottom photo shows a first working prototype; this is a big day for me.