Air Pollution Monitor

My family has the occasional opportunity to visit my wife’s and my home town. That is always a joyful time; we are excited to see the grandparents, parents, the rest of the family, as well as our old and dear friends. Unfortunately, during the last couple of years, those visits include certain restlessness – and this is due to air pollution. That is the reason why I have decided to make a small personal contribution to the potential solution of this problem.

Niš (foto: Vanja Keser/JV)

Since the air quality measuring is not performed in a robust, reliable, systematic and transparent way, I have decided to tackle that side of the problem – by building air pollution monitoring nodes.

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Homy 2.0

After a couple of years of the uninterrupted operation, I decided to retire the existing home automation and replace it with the new one. Since the technology available to the amateurs today is much more affordable, both when it comes to the simplicity of the use and integration but also the price. It is easy for the enthusiasts to combine the state of the art stuff like WiFi and LoRaWAN communication, open source home automation software, ESP8266, Arduino, …

In this post, I describe the various upgrades I have performed on the system during the course of one year.

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Elektro Pioneer – remotely controlled motorized baby stroller

Some time ago, a life-changing event influenced the ways I had been organizing my free time. The focus has been moved from the home laboratory towards two young creatures. That was one of the reasons I haven’t been much active with my hobby. I haven’t fully given up on the small projects, just reduced the time I was spending working on them and publishing the results.

Nevertheless, the parenting can bring different ideas to the mind of an engineer, and what I would like to show in this post is one of those ideas I actually went through materializing. As some of you (parents) might know, the really important item in any house with babies is the stroller. Zillion different types, a lot of time invested in selecting the right one, but eventually the stroller quickly becomes old news.

Elektro Pioneer

Somewhere around that period I got bored with the traditional use of the strollers and decided to try to motorize it and make it remotely controllable. The prototype has been finalized in mid 2013, and in the rest of this post I will describe the whole process.

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Balcony irrigation

A couple of years ago, I have installed the automated irrigation system in our apartment. After running this setup for an year, I have discovered some problems during the everyday operation:

  • due to the small capacity of the water tank, it was required to refill the tank frequently,
  • amount of water delivered to the plants was determined by time (averaged measured value I got with calibration) and was not accurate,
  • it was not possible to irrigate plants independently,
  • couple of times the whole water tank was used for single watering thanks to basic physics in action and lack of the valves.

In a meanwhile I have decided to automate the watering of the balcony plants as well, but also to fix the problems noticed in the first implementation. Continue reading “Balcony irrigation”

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Monitoring temperature and humidity

For almost a year I was playing with various temperature sensors and Arduino. Initially the plan was do use some cheap DHT11 sensors in order to measure soil moisture. After running number of tests I found this method not so reliable. Then, I put a number of DHT11 sensors in the house in order to measure temperature and humidity. Out of 10 sensors, only 2-3 were detecting correct temperatures. Then I tried DHT11’s bigger brother DHT22. The results were much better.

The idea for this project was simple and already seen in number of different projects around the Internet:

  • install a wireless node in every room of the house and collect temperature and humidity,
  • send this data to the central node (using the same (upgraded) central node described in previous posts),
  • store data in database,
  • display data (web page, iPhone notifications).

System overview is displayed in the picture below:

System design
System design
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