Wednesday, June 22, 2011

Basement Sensor

My previously mentioned tutor and nerd mentor who enabled me to get started on this project took one look at my code and found the mistake that was keeping the basement sensor from working properly. Making its first-time ever screen appearance, I give you: the Basement Temperature (brown line).


The next problem to solve: why all the "noise" in the data during the second half of the day? We have a few guesses but don't have any firm convictions at this point but we're assuming that something is happening to drive a single measurement to an unreasonable level. The proposed fix is to throw out all unrealistic measurements either based on absolute limits (no temperatures greater than 200'F and less than -30'F) or a relative limit (no temperature change more than 50 degrees away from the previous measurement). This will complicate the code slightly but, hey, that's what nerd friends are for.

Sunday, June 19, 2011

Whole-House Fan and Attic Temperature

A year or so ago we installed an Airscape whole-house fan. The fan is supposed to provide cooling to the house in two ways:
  1. Pulling cool air from the outside into the living area, replacing the air in the house as well as cooling the interior structure of the house.
  2. Displacing the highly heated air in the attic with cooler air from the outside (via the house).
We've been very happy with the cooling the fan provides to the living area of the house but we've had to simply assume that the fan was adequately cooling the attic.

Until now.

With the installation of my super-nerdy temperature measurement system, we now have proof that the fan is doing its job. Last night we turned it on as we we're going to bed, knowing the overnight lows would be cool enough to provide benefit. Looking at the graph, you can see around 10pm when the fan turns on the attic temperature (green) drops pretty quickly.



Nice the see our assumptions were correct.

Wednesday, June 15, 2011

Nerd Project: Household Temperatures

I spent most of Saturday crawling around the attic and drilling small holes in the ceiling to complete a project I've been batting around for over a year now. Since we put in our whole-house fan (about a year and a half ago) I've been curious to see what effect the fan would have in reducing the temperature in our attic. This got me thinking about temperature regulation in our house in general: the basement having much smaller changes in temperature during both the winter and the summer, the temperature in the two bedrooms we've don't used and have closed off, how much cooking in the kitchen heats the house, et cetera.

Enabled by a friend of mine who loaned me a critical piece of hardware (because he's even nerdier than me and had extras just laying around his house), I built a little system that measures the temperature in six locations around our house throughout the day. This collection of little programs creates an internal webpage that shows the current temperature for all six locations in the house and every morning creates a graph of the previous day's data and adds a link to that graph on the webpage.

Here's an example from yesterday.

A few items of note:
  • The dark blue line for our garage shows a little ramp starting around 5:30am. This is when we started the clothes drier which vents into our garage and thus, warms it up. My wife has been interested to see how pronounced this effect is and whether we need to try to modify the venting so it dumps the air outside.
  • The spike in the purple line a little after 6pm is dinner being cooked. Again, another wife-requested measurement.
  • You can see attic (green) gets very hot during the day, hotter than the outside temperature. It was too hot yesterday to run the whole-house fan so there was no circulation in the attic. This data seems to suggest that getting some kind of attic fan that ventilates the attic better throughout the day may help in keeping the house cooler. We've got a fair amount of insulation but with the temperature knocking around 130'F during the peak of the day when the outside air is barely at 90'F, it seems like our attic could be acting as a heat source and some of that heat is sure to be leaking its ways back into our house.
  • Relatedly, the garage is definitely getting warmer than the outside our throughout the day as well. More insulation between the garage and the house would help but an easier solution may be to open the garage doors to allow the air to ventilate. There are plenty of hot days left in the summer to try this.
This system has been running for a few days now with only minor hitches. The biggest bug is that I something is wrong the basement measurements. I know the sensor is good as it was the first (and easiest) one to install and I used it as a proof-of-concept. I've been talking with my nerd-enabling friend and we've got a few ideas I'm going to pursue. I'm also a bit perplexed at how noisy the data is at times. The indoor data (kitchen and hallway) seem very smooth but the rest vary much more than I would expect. Maybe its not noise and the temperatures do vary that much.

Aside from adding a few more sensors (closed-off rooms, maybe the bedroom and the living room), I would also like to add sensors that detect when the whole-house fan is running and when the air-conditioning/furnace fan is running. I hope to get those last two in sometime this summer but I need to figure out the best/easiest way to do it.

I'll write another post soon in a few days detailing the specifics of how the system is put together for any fellow nerd out there who is interested.

Monday, June 13, 2011

Infant Rabbit Update

After about 24-hours of peace and quiet away from Anise, our little guys seemed to be doing fine (psychological damage aside) and so we decided to release him back into the wilds of our backyard. He spent the first hour or so just huddled in the grass. By the time I was leaving for work he was starting to be a bit mobile and explore around. When I came back from work, he was gone. Here's hoping he survived.

Anise did find a sibling of our friend (also under the deck) and after using it as a toy for a few minutes, managed to kill it. I buried it in the side yard out of Anise's prying nose and paws.

Hopefully this is the last of our infant-rabbit woes. Anise is still carefully exploring the deck for opportunities though she hasn't been barking like she did before. The family may have moved on.

Thursday, June 09, 2011

Half-Way

For several days now whenever we have let Anise outside to run around and get out some of the crazies she has been trying to get under our deck and, failing, barking animatedly. This is the same thing she does when there is a rabbit out of reach (in the neighbors yard, across the street) and she is excited by the possibility but frustrated by the circumstances. This morning she found a way under the deck and shortly thereafter a rabbit did emerge. A very small rabbit.

I have no idea what transpired under our deck this morning. The rabbit that emerged had a small amount of blood around its mouth and one eye appeared to have been permanently damaged. It was making small, pathetic squeaking sounds and was laid out on its back, chest heaving but otherwise unmoving.

What do you do with a half-way dead infant wild rabbit?

We couldn't leave it laying there but we had and have no interest in a baby rabbit for another pet. We choose to give it shelter for the morning, to try to make it as comfortable as possible. We fully expected it to be dead within the hour and made a home that would be easy to bury when the time came. I found a spot in our basement that they dogs can't get to and where its nice and cool. I left two ice cubes in the improvised water tray we were using along with a portion of a leaf of lettuce and small strawberry before I went to school that morning.

This evening when I returned it was still alive. It seemed to be resting and though not moving around in traditional rabbit style, it was clearly still able to move. We're going to try to assess the situation more clearly this evening.

The end game isn't very clear to me. Do we hope to nurse it back to health and set it free? Where is its mother? What if it has been permanently injured in a way that will make it impossible to survive on its own?

Its hard to say what were going to do with this little fur-ball our dog thrust into our lives.




Its not clear from the photo but the little guy is only a few inches long, more like a mouse than a rabbit.