The evapotron is coming along. Here’s what works: first, the junction box is done, and the control box is about 80% built. I’m still having trouble getting stuff to adhere sufficiently strongly to the inside of the control box, but there’s progress (clamps are the answer: let the glue set with everything really tight).

The voltage, reservoir level, and temperature sensors work fine. The flow sensor works in a wonky way, sometimes ok and sometimes it just stops (there must be some bad wiring somewhere, haven’t found it). The Arduino can switch the pump on and off. The operational state data and sensor data is logged to a SD card, and there’s an LCD display on the control box which gives whatever data we want.

In the control box, I need to shift the 12v power bus from the big screw-down versions (from which wires often escape) to wire snaps, but that’s mostly done. And I’m shifting the mount point for the Arduino, perf board, and voltmeter to the top where they’ll be way easier to work on. That’s an hour, broken up into several gluing and drilling sessions. But it solves the LCD mounting problem, which is a win.

The power circuit isn’t started yet, but it’s simple. There will be a relay for each battery and one for the charger, and that’s it.

And the current sensor from Sparkfun doesn’t do anything. I want it to tell me when the pump is running (which is different from when it’s switched on), and how much it draws. I’m not really sure even how to go about this one.

The software is pretty nearly done. The outstanding pieces are about harmonizing all the different elements, and that’s actually the easy part. Getting each piece to work has been a long road, though. Nearly there!