2023-03-14
So here is an interesting topic – a cheap Chinese electric thingie performed better than advertised. Specificially a 240W DC-DC converter; 12VDC in, 24VDC out. It claims to be able to turn 20A of 12VDC into 10A of 24VDC. With the checkered history of price-concious Chinese products one may rightly be skeptical of such claims. And that’s why this genuine Gofotu H10-12-24 both surprises and delights. Not only does it live up to it’s claims, Read more…
2022-06-13
Well you get this: … a monitor stand attached to a pipe stand via C clamps.
2021-05-28
I haven’t tried to peddle fuck-ups as wisdom for a while because I’ve been designing and implementing a fence with some chest hair. After doing some fancy arithmetic documented in the previous posts, it becomes very apparent why a fence that complies with code has 6 inch gate posts. And just in case you doubt me, and you very well should because I’m just some rando on the Internet, I can can tell you that Read more…
2020-08-02
I got a 20% off Harbor Freight coupon and got unreasonably gitty. I have been eyeing the 20 ton press and 20% off off ANY SINGLE ITEM* was something I felt was worth waiting for. But wait, what is that excitement tempering asterisk? I have reformatted for readability: *Cannot be used with other discount, coupon or any of the following items or brands: Inside Track Club membership Extended Service Plan gift card open box item 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…
2020-07-05
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…
2020-06-13
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…