It felt good to have a soldering iron back in my hand. Felt right. I’m in the process of channeling a new obsession into an old hobby. The latter is electronics design. The former is home maintenance and environmental awareness.
When we first moved in, it became apparent we had a minor microbial problem. It turns out that mold likes two things: moisture and warmth. We were also beset by a series of issues with the forced hot air system. Furnace cleanliness, closed ducts, and (as by brother was keen to point out) an open window were all contributing to a serious temperature difference between upstairs and downstairs.
So, I started thinking about ways to quantify these problems and more actively monitor my surroundings. I cooked up a nifty microcontroller project. Have an Arduino receive sensor information from a series of wireless nodes scattered throughout the house. The nodes would be equipped with temperature and humidity sensors. I wound up buying a Wicked Device transmitter node/receiver shield pair from MakerSHED. The kits come as an empty board and loose components. A little solder work, and we’re ready to write some code.
There are two software components required immediately: the microcontroller code to manage receiving the wireless data and forwarding it out through USB, and a daemon running on a PC to intercept and log it.
As a test run, I left one in the bathroom while (and after) I took a hot shower. I didn’t timestamp the data, but the node transmitted a packet every ten seconds. Some packets seem to get dropped, but that should give a rough idea about time elapsed. I’m also just too lazy to convert the data into actual degrees or percentages, thus no labels on the axes. This is all relative. Statistics faux pas, I know.
I left the fan running and the door closed during and after. The point where the shower ended is pretty obvious, but I’m rather surprised at how long it took for the conditions to get back to normal. Towards the end, I opened the door, causing the quick equalization at the tail of the graph.
Eventually I may push the results into a database and add more sensor nodes. Maybe even a web frontend to view the house’s current conditions in a visual manner, or graphically inspect logs. Of course, that will require more soldering. Bring it on.