Build an Air Quality Monitor with InfluxDB, Grafana and Docker on a Raspberry Pi (opens in new tab)

What is this, off-brand sarcasm?

> Measuring a sensor is so complicated

Well, you need something to ingest & query the data. InfluxDB or Prometheus is a good choice.

You need something compatible to display it. Grafana is perfect for that.

Docker is a pretty simple and decently-lightweight choice to standardize how this installs and runs.

And letting it run on a Pi makes it cheap and accessible.

What exactly is the problem with this setup? Not enough NIH?

    > Measuring a sensor is so complicated...

I get the sarcasm, but sometimes it is useful to exercise "big boy" tools for projects that don't need it.

What better way is there to learn/explore these things than with a very simple project that does something remotely interesting or useful?

I've built one of these types of systems without a lot of that technology stack. I have my own dashboard, use in-process HSQLDB for the back end, and have a deployment process build around uberjars, shell scripts, and init scripts.

https://github.com/mschaef/metlog

There are reasons I made the choices I did, and I think they still make sense, but there's been enough of various sorts of implementation pain that I am absolutely sympathetic to the idea that this person used some off the shelf software.

You should probably be more aware of your target's constraints and goals before you start questioning the means they used to achieve them.

At work one of the projects I work on is the telemetry system for a solar race car. I have pretty much the exact setup. We grab the data from the CAN bus transmit it over the radio to the chase vehicle. Data needs to be logged so you can create/test algorithms for predicting optimum speed for the car and also run the algorithms during the race. We don't use PI but a headless linux box will receive all data. During the race both the electrical and mechanical teams needs to see this data. Grafana pools the DB and everyone with a PC, Smart phone or tablet has access to the telemetry. Computers break if the server on the chase vehicle (centos box) breaks I will have reasonable confidance that I can run the telemetry system on my laptop (ubuntu box) with a couple of docker commands. So on top of OP I have a pinch of Clojure, Matlab, Postgres.

If you don't feel like setting up and maintaining your own data storage & visualisation solution for your time series data, you could use adafruit.io or blynk.io. And if you're really lazy or impatient you can try my ridiculously-low-friction service pushdata.io :)

I'd have solved it same way as the article, as they're tools I'm familiar with - feels like overkill though. How would you have managed it?

Hey there - BalenaOS is built to run containerised workloads on small devices and is quite stripped down otherwise, kinda like coreOS. So in that sense our architecture allows you to have less stuff you don't need floating around, saving you overhead. We focused on Docker containers since balenaCloud is built for fleets. It's important that our stack supports not just one but many copies of the same device running the same code, and then it can be updated in production etc, just like a set of servers. If one is optimizing for a single device, just naked Raspbian will do fine of course. Our approach has a bit of overhead up front in terms of setup, but you get a production ready setup from day one in return.

If you do not want to need 10 different RPIs for running 10 different functionalities (Pi-hole, RetroPie, remote access, cloud, side-projects, air quality monitoring, etc.), docker is a good solution to easily deploy several services on a single RPI, and it prevents dependency hell.

I can't understand why they would add anymore overhead on such a low powered device.

It gives you easy upgrades and nice dependency separation. It's not required in this case, but it sure makes operations easier. (Doing the same for multiple services on rpi)

Agree, an Ansible playbook would have easily suffice.

How accurate are these, anyway?

I run a Luftdaten module myself (with SDS011 particulate sensor), but with no government meteorological station next to me, I don't really have a reference point. All I can say is that this SDS011 spews out some numbers, and when testing indoors those numbers got higher when I turned on my air humidifier. I have a similar concern about DHT11/DHT22 - it's a random small box I got mail-ordered from China, which purports to tell the temperature and humidity of air. But again, those are two arbitrary numbers I don't have anything to calibrate again.

Just using these sensors and trusting the results is an accepted practice in DIY electronics community. But I keep wondering - are those sensors actually calibrated, or it's that people don't really care if they get garbage results?

(Related, it's also my number one complaint against a particular air quality startup in my country. They rent out air sensors which you can't inspect (there are contractual penalties involved), and they happily market their map as a vital tool for air quality, but nobody really knows what sensors they're using, and they don't even bother to put error bars on the values they show. I mean, I thought including measurement error is how adults behave.)

Assuming I have no idea about these things, which is true—I don’t—how much is a decent CO2 sensor that can be connected to a Pi or similar setup?

I recently upgraded to double glazed windows in half the house, including all the bedrooms, and put a heat pump in each of the two used bedrooms. So I want to keep the windows closed for heat retention, but also want to keep them slightly open to reduce CO2 build up.

I sleep in my small bedroom with my two 16kg dogs, so it seems reason the CO2 level may rise to suboptimal during the night if the window is shut.

What I would like to do is make a DIY ventilation system that can move fresh, HEPA filtered, air from outside, in to the room.

Or am I over complicating things? Could I just use a small fan, something sized to replace, say, half the volume of the room every few hours, and just leave it constantly on? Or should I put a larger fan on a timer so it runs for a few minutes every hour?

Does any of this really matter?

Edit to add: any good resources to lose myself down a rabbit hole?

CO2 sensors are available for about 20€. MH-Z19 or MH-Z14 are common ones.

Can anyone recommend a better sensor? I’d like to build an upgraded version of this - that way I’ll also learn more.

Since indoor air quality/IAQ is a composite metric, I'd say that some of the interesting things to measure are:

    PM2.5/PM10 - particles from combustion, exhaust, traffic (wheels against asphalt) etc
    CO, NOx - from traffic exhaust
    CO2 - from humans
    VOC - volatile organic compounds, IIRC correlated with cancer and lots of unpleasant stuff. Comes mostly from paint and manufactured stuff (furniture etc) at home.

I'm about to make a small sensor thingee that measures these plus relative humidity (too dry at home, 30--50% should be good, we're at 10-15%), temperature (16-20 when sleeping), and for fun barometric pressure, ambient light.

For this I'm going to use a Honeywell HPMA-115S0, and IIRC BME680 and some other stuff. If interesting I can have a closer look. Battery-operated devices are a little bit of a challenge since often some of these sensors internally use a heating element for a long duration, so they consume quite a lot of power.

The Plantower looks interesting, thanks for the link.

The sensor doesn't appear to measure particulate matter, so I'd take the air quality reading with a large grain of salt.

For anyone else who goes looking for the datasheet - the link from the shop is broken but is saved in the wayback machine.

https://web.archive.org/web/20180130060734/https://ae-bst.re...

Someone replied with this interesting and then deleted their comment. It doesn't include the same sensor, but it does include a related one and it's a wonderfully detailed analysis:

Thank you for linking it!

https://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_many.h...

I was really keen on the Awair, but the necessity to be connected to wifi to function was a deal killer for me. From what I've seen this will never change which is disappointing.

Did you simply use one Awair device around your entire house?

Unfortunately, only shipping to the US & Canada.

We have a new house--about a year old now--here in Texas with all the efficiency and insulation stuff. I noticed after working in my office with the door and windows closed I didn't feel so good after awhile.

I got one of those trendy Awair monitors and stuck it on my desk and hooked up the iPhone app. And sure enough, when I started not feeling well it was because the CO2 was over 1500 ppm.

I don't know about the accuracy of the actual CO2 measurement, but I figure the delta is at least good enough to spot trends. And yeah, those times I don't feel well is always associated with a rise of CO2. I "fix" it by either opening the door and/or window or running the fan of the central air system. Our system also has a "bleed air" adjustment for outside air. I turned that up a bit, too.

The Awair also does "chemicals" and PM2.5. I'm surprised our new house doesn't an issues with those, but I do see PM2.5 go up when the window in my office is open and "chemicals" fluctuates throughout the day but at a low level. I'm not exactly sure what "chemicals" means in this context; I haven't really looked into it yet.

You might consider the Awair; I've been happy with it. I have several thousand systems that need tending at work and, same as you, I don't need to come home and do more. My wife's Windows gaming rig needs enough of that as it is...

Most air quality measurement involves particulate matter, specifically PM 2.5. This is primarily wood smoke, car exhaust and a couple of other combustion-related. When the news talks about air quality, most commonly they are referring to PM 2.5.

If you are looking for out-gassing (paints, carpets, furniture etc) you probably need to invest in formaldehyde and other gas sensors. In your case you ought to look at your furniture and electronics as they will produce the most out-gassing. This is different from the above particulate matter.

Here’s a lab writeup comparing a few models from about a year ago:

https://smartairfilters.com/en/blog/are-cheap-particle-count...

Depending on which part of the Middle East you’re in, you may need a PM10 (dust) monitor. The devices here just do PM2.5 (smog).

What do you want to measure? Saying you need it to be super accurate doesn't mean much on its own. Air quality is subjective in any case.

The BME680 (like other chips) measures VOC content - organic stuff like alcohol. You can also measure dust concentration, for example if you lived in China, PM2. 5 would be good to know. And you can also use CO2 concentration, but good CO2 sensors cost a lot. Some chips measure "equivalent CO2" but it's not the same.

Real question, why?

I'm running grafana + influx and it's doing the job well. The netdata git repo is full of marketing fluff and fails to convince me it's any better.

That's a good point! We should try that as an alternative next :)

I'm using a very similar stack! I've built 20 devices using the PMS5003, Spec Sensors O3 digital gas sensor, and a cheap GPS module connected to an ESP32. 6 have been mounted in the field (more coming soon!). They report sensor readings via LoRaWAN to a public-facing dashboard visible here: https://graqm.org

Devices being tested at an EPA air quality monitoring station: https://imgur.com/a/joQvj

Desktop version: https://imgur.com/a/yT1IK

SD cards fail but they're not a house of cards. I've logged into couch dB every minute for nearly 5 years. only about a million entries bit since it's replicated to other nodes a failed card is ok.