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…
2020-03-30
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…
2020-01-25
It has been a while since the last update and a whole lot of progress has been made. On the software side everything seems to work. For realsies this time. The full software stack compiles and runs(!) on both Linux and FreeBSD. On Linux it compiles using GCC and Clang. On FreeBSD only Clang is used since that’s the default compiler. To be fair I’ve only tested the client side stuff on FreeBSD, but as Read more…
2019-09-22
The hardware design is complete. All of the units that I will assemble have been assembled. The software is good shape. It hasn’t been touched in a few months, but last I worked on it it was in very good shape. The next step is actual physical assembly of the whole thing. Below are a few select pictures of the assembly progress. All taken with PotatoCam II. Where the magic happens, one of two. The Read more…
2019-09-16
Final assembly has begun. While waiting for the parts for the Beagle Bone expansion boards I started assembling the IO boards. I figures four at a time was a good idea. Find all the location on the first board and then copy that to the other boards. One component at a time of course. I was wrong. Five hours into this, my solder paste is getting dry, I’m getting anxious from sitting in one spot Read more…
2019-08-26
The VPSB (Vic’s Serial and Power Board) is functional. Fucking finally! The last function to be tested was the current monitoring of the attached peripherals and I am glad to report that it works. Not flawlessly, unfortunately. I will have to replace the 0.010 ohm resistor current sense resistor with something a bit bigger on “production” boards. Going to try a 1.5 ohm in its place. With two 3 ohm resistors in parallel current sensing Read more…
2019-08-19
How do I put this … the latest revision of the board works. The only thing that I haven’t delved into I2C, but everything that I have tried so far works. Completely. Which is actually extremely rewarding, since this has been a slog for a year plus. Some previous posts to catch you up: So much failure More failure Everyone on the fail train Well all of the problems have been addressed. Vic’s Power and Read more…
2019-08-04
Finally success. FINALLY. I finally have inrush current management under control. In case a refresher is needed, here are a few posts discussing the problem. https://www.simkus.com/2017-10-01/ https://www.simkus.com/2018-07-21/ https://www.simkus.com/2018-08-24/ To recap: Attempt #1 – relay. When the relay would turn on, the power supply would dip causing havoc. Attempt #2 – PWM drive of the low side. Electrical current is like love – it finds a way. By disconnecting the low side (negative rail), the positive Read more…
2019-07-30
I have been playing with the latest revision of the VPSB (Vic’s Power and Serial Board). I was hoping that this would be the last revision, unfortunately the fact that I crewed up the power supply footprint will prevent that from happening. I got the pin order backwards. This is the worst kind of failure since I can’t blame anyone else. Anyways, here’s the potato-cam picture: You can see the power supplies in the Read more…
2019-01-04
Long story made short: more failure. One very basic failure was mixing up SSOP footprints with TSSOP footprints. I have a laundry list of excuses for screwing it up, but at the end of the day a lesson has been learned that should have been learned many times over in the past – don’t try to hand-wave things away. Experience is the name we give to our failures, I suppose. A more subtle failure was Read more…