Date: 01.25.15 - 3:32am
this winter I decided I would try to run humidifier to see what kind of difference that made. Winters are extremely dry in the frigid North and average humidity can be below 10%. Also I will admit the lower the house humidity the faster my cigars dry out in the humidor, so I could kill two birds with one stone.
I looked around a little bit and ended up settling on a Honeywell quiet care unit
I ran the unit for a couple weeks manually, however I was having to fill the tanks twice a day. This quickly became a chore and I did not see myself reliably being able to continue doing this so thoughts turned to home automation and Arduino. I considered several different routes, and I think I came up with a pretty good solution.
An Arduino controls a solenoid valve to a water line. I timed how long it takes to fill the reservoir in the base with a stopwatch. I also timed approximately how long it takes for the humidifier to run empty. This time however is variable because sometimes the humidifier shuts itself off if humidity gets too high, or if humidity is extra low it will run out faster. It any rate the time scenario gives us a decent rough estimation. in order to catch the scenario of over fills, a high water sensor is added that will immediately abort the fill if it becomes wet.
So the basic logic is, fill for X seconds, abort if sensor wet. Sleep for X minutes, repeat.
It is actually a super simple thing to automate and saves you a lot of time! pretty much just runs constantly now all on its own this was a great home automation project that had real effect :) I have made the source code for this sketch publicly available as well. Below is a video of the setup that I used:
the only critique that I have after running it for a bout a month straight, is that the water sensor is corroding itself a way. The good news is is that when it's heavily corroded it shorts out and sends I am wet signal as opposed to just not working and allowing an overflow to happen. I was wondering why the sensors were so long, it's probably because they are meant to be cut back as they fail giving you a longer lifetime of use. So far I have cleaned it twice in the last two weeks wedge compared to the work of filling tanks is acceptable although still slightly annoying. Note that the sensors are no good at detecting water depth which supposedly they were capable of. The corrosion you are seen in the pictures below looks like typical anode cathode type ( note how it is only every other strip) so it's nothing to do with the water itself just the amount of voltage going through them.
I could use an ultrasonic distance sensor to read water level, but I also read a post online that the little speaker material if wet from humidity or missed could fail, I'm not sure of the intensity of the users application mine is absolutely minimal.