neat.... now will this current change be consistent in different filters or do you need to calibrate the code depending on the filter?
I was hoping to make my own controller, but it keeps getting pushed back. So I haven't extensively tested how different filters behave. I know my Magnum 350 and Aquaclear 70 both show similar behavior, but didn't record numbers.
Personally, I wouldn't get fancy with it by putting in any kind of calibration, that may or may not work in any particular case. Allow the user to view the current consumption, so they can get a baseline value when the filter is operating normally. Allow the user to turn on current monitoring, and program in an upper and lower current limit. I would suggest +/- 20% as a good starting point, but leave that entirely up to the user.
By making it both simple and flexible, it reduces developer effort, and users may find other uses for the feature that we haven't thought of.
Another feature that isn't too hard would be to add the option to power cycle the device at five second intervals a few times before sounding the alarm. That sometimes frees a jammed impeller with no user intervention.
Detecting media clogging would require some sophisticated code and I'm not sure if it's practical or possible; I just haven't had time to look into it yet. Since this is an open source project, people could experiment with that later. Other than the current sensor for each monitored outlet, the only additional hardware feature required to explore this is a way for the MCU to monitor the AC voltage waveform (one per controller, not per outlet). Easy to implement and might be useful for other things too.
btw. How do you measure current without accidentally blowing a fuse in your meter?
LOL! Unlike measuring voltage, you cannot just connect one lead to hot and the other to neutral. That will measure the maximum amps the outlet is capable of supplying, since in current measurement mode the meter is a short circuit.
Don't feel bad, it's a common mistake and I frequently buy new meters at work because people try this.
Instead, you have to break one of the connections, either hot or neutral, and use the meter to bridge the break; with the meter on the appropriate setting and the red lead plugged into the 10A (or similar) socket on the meter. Obviously this requires some sort of rig, since you normally don't want to cut one of the wires on the cord of the actual device being tested. A short extension cord with one of the wires cut in the middle, and both ends stripped and exposed, can be used. Just make sure no one else tries to use it as a regular extension cord, and don't come in contact with the exposed wires while you're testing.
A $20 Kill-A-Watt meter makes this foolproof. You just plug it into the wall, and plug the device into it:
It comes in handy, and has some extra measurement modes not found on a typical multimeter. In aquarium use, I've also used it to determine approximately how much power a ballast is actually pushing through a mismatched fluorescent bulb, like in ODNO setups. Also very nice for tweaking power settings on computers to see how they reduce consumption.