Category Archives: Uncategorized

The old, static website became harder and harder to maintain, so I finally switched to using a CMS. WordPress offers some nice options but it is also frustrating to lose the full control over the page layout and effects. Overall, it should still make the page much easier to update in the future. As a bonus, the update also fixes the broken responsive design of the old page.

The goal for the second iteration of this project is to make it less centralized. Sensors should be independent of logging and visualization. After version 1.5 this is already achieved partially: database and graphing run on my home server and the sensors are connected to an independent Raspberry Pi. Only reading out a few sensors every couple of seconds is no challenge for the Pi but wastes power. Running a full-fledged operating system for this simple task is just too much overhead – almost every micro controller can do that. Since I know python but I’m not as well versed in Arduino, C or similar, I would like to use a micro controller that can run python. Although python requires higher perfomance by design, there is a number of capable micro controllers out there today. The ESP32 is also overkill in terms of performance but I wanted to play around…

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In 2018, a colleague mentioned to me that he found a nice CO2 monitor with an undocumented but open USB connection. On Github, vfilimonov wrote a nice python package to decode the USB connection and show the measured data on a website. From this starting point on, I experimented with further sensors and a more complex data acquisition, storage and visualisation. The current state is an experimental setup running on a Raspberry Pi 3B+. Several sensors are connected to test and compare them. Connected sensors are: TFA Dostmann AirCO2ntrol Mini CO2 Monitor Two DHT22 temperature and humidity MH-Z19 IR absorption CO2 sensor 0-5000ppm TSL 2561 light intensity sensor BMP280 digital barometer The monitoring system in the configuration as used in the following. Raspbian Buster runs from an old SSD that also stores programs and databases (black cable with two USB port because the Pi cannot supply enough current). The white…

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As mentioned in the introduction to the homeclimate monitoring project, I run a small unRAID homeserver with a couple of disks to provide some services in my local network. Besides monitoring the server itself with the TIG stack (Telegraf, InfluxDB, Grafana), it is also interesting to monitor power consumption to find out what the server costs aside from the initial cost for the hardware. Self-made solutions operating on mains voltages is always tricky and the potential risks are large. Luckily, there are a number of cheap and easy commercial options. I opted for the “TP-Link Kasa smart plug HS110” which is available online for typically less than 20€. The HS110 can monitor voltage, current, power and turn on/off the integrated outlet remotely. It also has smart home feature (e.g. Alexa skills, Google Assistant, IFTTT) but I don’t need nor want those. Still, it is one of the cheapest and also…

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