2020-07-20
Now that we have a defensible way to calculate wind force per square foot of fence we need to put that to practical use. The main load bearing part of a fence is the fence post. We’re interested in the load generated on the post above the ground where the fence attaches to it. This will also play into the footer design later. The way fence post loads are calculated, and I swear I saw Read more…
2020-07-19
One of my next substantial projects is building a fence. Because of the type of person I am (insufferable) I want a fence that’s better than the standard ‘stick a 4×4 in the ground and nail some wood onto it’ type of fence. Not that there is anything wrong with that type of fence, I just want better. As part of the project I though it would be fun to go through and do the Read more…
2020-07-14
Well it has been done. 110F has been broken bbb_hvac=> select * from data.home_data where attic_temp = (select max(attic_temp) as attic_max from data.home_data) order by time_stamp desc; row_id | time_stamp | ac_compressor | ahu_fan | ahu_heater | ahu_return_temp | ahu_supply_temp | attic_temp | space_1_rh | space_1_temp | outdoor_temp | outdoor_rh ———+—————————-+—————+———+————+—————–+—————–+————+————+————–+————–+———— 8725659 | 2020-07-12 17:09:10.715058 | t | t | f | 73.6723 | 57.9939 | 113.597 | 57.2703 | 71.1624 | 94.1 | 59.5273 Read more…
2020-07-12
At the time of writing this post the outdoor temperature is 96F. This is according to the Google and verified by my personal temperature/humidity probe. It’s also very sunny with not a cloud in the sky. So what’s the attic temperature? I’m expecting a fairly high number due to high outdoor ambient temperature and lots of sun. Drum roll please … the system measured attic temperature is 106.1F. Not as high as I had thought Read more…
2020-07-09
In the last post I did some basic arithmetic to see if the system as designed should be able to measure 110F. This post is about verifying the physical reality to see if matches the pristine mathematical theory. To turn the VICTD into temperature in Kelvin the function is below. We know this from the previous post. $$T_K = V_{ICTD} \times 10^3 $$ Measuring the output of the probe I get a reading of 0.30111V. Read more…
2020-07-05
My home AC has been operating (fitfully) under the control of my system for a few weeks now. While doing so it has also been logging various parameters at one second intervals. I thought it would be interesting to look at the data. The first question was: what is maximum attic temperature. Since all of the data is in a Postgres database, that’s a very easy question to answer: bbb_hvac=> select max(attic_temp) as temp_f Read more…
2020-06-15
So this contraption that’s been in the making since December 2016 is officially controlling my home AC. Additionally, it’s logging all of the operational data of the AC: operating state, supply temp, return temp, space temp, space relative humidity as well as attic temperature, outdoor temperature, and outdoor humidity into a real database (PostgreSQL) at one second intervals. Here’s the complete install. Yes I know some covers (and screws) are missing. I’m working on that Read more…
2020-06-13
I don’t think that it’s an awe inspiring revelation that new ideas are sexy and exiting. Starting new projects, developing new designs, and shopping for and putting together BOMs is exciting. What’s not sexy and not exciting is working on the last 5% of the idea. The grinding out of the bugs and refinement of ideas and dealing with design decisions that you have no one to blame but your self. That’s where I’m at Read more…
2020-03-30
I have been working on integrating the grossly over-designed and needlessly complicated thermostat into the house. It has been mounted in the data closet (see here) and connected to the home network. All critical sensors and some of the optional sensors have been been installed. Of the optional sensors the attic temperature and the AHU supply air temp sensors have been installed. More on that later. The system is not yet controlling the house AC Read more…
2020-02-02
This post is meant as notes for me. Do not expect the wittiness that you’re used to. The goals is to have my home server collect and store the data generated by the home automation system. In addition to the collecting it I want it to be able to “analyze” the data. In other words I want a pretty graph. The data is stored in a PostgreSQL instance. The analysis interface will be web-based. I Read more…