Bazsi's Home Automation blog

In the past installments of this post series, I was writing about how I, as a software engineer, started troubleshooting the heating system in our new house. This all started by acknowledging there was a problem ( part I ), understanding the basic heating components, such as manifolds ( part II ). Smart thermostats and PID controls ( part III and part IV ). The solution needed in-depth monitoring/debugging so part V was about 7 pieces of DS18B20 sensors and a Raspberry Pi, I've installed in the boiler room. The solution was a bit of a surprise and may I add, I was kind of shocked about the simplicity of the solution once I knew the issue. Remember, that the original reason I started the whole exercise was to make comfortable temperatures in the house, as it was a bit cold. After I've excluded all relevant problems (manifests, water-flow, thermostats, pump, etc), all I had left was to increase the boiler temperature, thereby increase the temperature of the water in the...

In this series of blog posts I am revisiting the process of troubleshooting the heating system in our new house. In the past installments I've described the most important elements of the system (and the ones I fixed), since those didn't reveal the true issue with my heating, I needed to go on. This post is about my monitoring gear. Temperature sensing was a key element of finding the solution. First of all, I have a number of analogue temperature gauges around the boiler/furnace, each attached to a specific section of the system. What I had to learn was that these gauges are very slow to react, and thus were pretty much unusable for my goals. If your temperature has very low volatility, they might be fine, but if you want to understand how and why temperature changes, you will need something that gives you a reading every 10-30 seconds. To address this problem I used a dormant Raspberry Pi and a pair or Onewire sensors I had lying around. These were of the type DS18...

This post is a continuation of my last post about KNX thermostats , which is part of my series about the troubleshooting of our heating system. In the last post I gave a "software sided" intro on our smart thermostats, but I've found the control theory behind these devices even more fascinating. But first of all, let me introduce you to our thermostats: As you can see, there are some leds, a push button and a rotary control labeled from -3 ... +3. The leds indicate the current operating mode (comfort, standby & night mode), as well as frost and heat protection. The rotary control allows the user to customize the temperature in the room: the mid-point is set with KNX parameters and the user may subtract from or add to maximum 3 degrees to that value. I mentioned in the last article that the midpoints were not set to the same value, which could explain some of the temperature differences. I also mentioned that you can set an adjustment to the temperature measu...

As described in the previous incarnations of this series ( part I: introduction , part II: heating manifolds ), the heating in our new house wasn't working very well, and I was working on finding out the root cause, as someone without too much proficiency in mechanical engineering, but with a software engineer background. This installment is about our smart thermostats connected to a KNX (aka EIB) based backbone , that control the valves (turn on/off) on our heating manifolds for per-room temperature control. I described in the previous post, I was suspicious of the thermostats, as some of our rooms were set to the same temperature, and one was warm while the other was cold. These thermostats have a couple of parameters that can be adjusted that would significantly change their behavior. The most important ones from my perspective are the temperature adjustment: to offset to be added/substracted to the measured temperature to counter potential sensor errors the base setpoi...