Do you really need an excuse to start a new project? There is an abundance of data available these days but it occurred to me i still know next to nothing about the environment (home) i reside in a significantly amount of time. Lets change that.

The goal is, simply put, to have a bunch of sensors and start collecting data to analyse and possibly trigger alerts. Since i want to store and host everything locally i will not be using any cloud services. Because of budget constraints (and preferring, more expensive, accurate sensors over more data points) i will not have multiple sensors of the same kind (e.g. monitor multiple rooms and/or outside/inside). This severely impacts the chosen system architecture. Arduino is very well suited to create efficient sensors devices (hubs) sending data back to a server but i will only have 1 sensor hub and am more interested in software than hardware. Therefore i have decided to use the Raspberry Pi1 (4B) as platform for this project. It will be running headless2 and have all sensors connected to it, wired. This means i will have a server running 24/7 which opens possibilities to use the Pi for other purposes as well. It also helps to justify the cost of the project. If it were only processing sensor data even a Pi Zero (W) would have been more than enough for the job.

Now the focus on the software side also impacts the sensor selection, i will limit my search to sensors with a soldered on a breakout board. This will drive the cost up significantly and reduce the options. Creating my own PCB was out of scope (but could be an interesting project on its own). Any solutions which would require significant hardware development were discarded as well. In addition i wanted to avoid having to calibrate sensors periodically, or even at all, since i do not have good reference equipment at my disposal and would never fully trust it otherwise. Unfortunately i will have to make concessions on this front due to budget constrains (professional grade equipment is too expensive to justify as a hobby project; for me at least). For ease of mind the goal is to have a set and forget project (which is a bit the point of measuring data over time).

Because environmental sensors are popular there are ready to go kits (often open source) available which have the same purpose as this project and often have a website and mobile app as well. While some of them are certainly good I have opted not to use them and put the project together myself. This way i will get more out of it (learn).

First up, sensor selection!

  1. there are other platforms available as well, e.g. Orange Pi, or you can go for a NUC system and connect the sensors through USB (I²C or UART adapters). ↩︎

  2. without monitor, keyboard and mouse attached like a regular server. All configuration and interaction is done remote usually through a ssh connection or website hosted on the device. ↩︎

Noticed an error in this post? Corrections are appreciated.

© Nelis Oostens