It might seem simple task but it involves some tricks to control motors and read sensor data from two separate controllers.
One of the challenges I faced is meshing position and temperature data. Feedback received from each controllers is timestamped. After scan is complete timings are being analyzed and each temperature value is assigned interpolated coordinate from motor feedback. If done incorrectly (brute forced) this procedure can take hours. Luckily there are tricks to speed this up to few seconds. Hint: Python numpy searchsorted.
Another annoying (but luckily easy to fix) task is correctly and evenly visualizing data. Unless you oversample few times there will be black dots on complete picture. In photography they are called dead pixels. In our situation it is pretty easy to spot these pixels and filling is done by averaging neighboring ones.
Michael from Acidbourbon has built the “perfect” tea timer project. He wrote a post on his blog detailing its assembly:
Maybe you just drink coffee. Then this article is not particularly interesting for you. But if you like a cup of black or green tea once in a while you might know the problem: You prepare your tea and you let it stand for a minute too long. Then it is bitter. So the next time you use the timer functionality of your smartphone … unlock the screen, open the timer app, enter something like “3:00″ (minutes), press start, pour boiling water over the tea, wait. Then your phone beeps like crazy while you are fumbling around with the hot and wet teabag you want to dispose of. Finally you unlock your beeping phone with your wet fingers, open the timer app again and silence it. Pure stress.
Of course that is a first world problem and you could just deal with it. Or if you are a tinkerer, like me, you might want to build yourself the perfect tea timer. The desired properties are:
Extremely simple user interface
When finished it plays a short melody and goes to standby by itself
Long battery life
OpenDrop is a new design for an open source digital microfludics platform for research purposes. The device uses recent electro-wetting technology to control small droplets of liquids. Potential applications are lab on a chip devices for automating processes of digital biology. How ever the present design should also open the technology to other field and allow experimentation to find new applications. Including the field of art, music, games and education.