Environmental monitoring

The new Faikin Remote have sold a few, nice. Thank you. Now on Tindie, and more coming soon. The BLE linking to Faikin is working really well now.

But ironically more have sold not as Faikin Remote, so far, but as environmental monitors. The boards have pressure, temperature (via many means), humidity, and CO₂.

What is even more amusing is that the monitoring is probably best done using my generic display signage code (EPD) as it has all the sensor code to allow display of the values. No link to Faikin, but links to Home Assistant, and simple http polling, and so on, for all sensors.

Irony on top of that is I have had to just make a version of my display code for no display, a blind version, as it is ideal for this monitoring application even when you have no display (data centres, etc).

Home and office monitoring of CO₂ levels is becoming more important as people realise how much of an impact a lack of fresh air really has.

Carbon cycle

I am pretty sure I did cover this in school, but I did not quite appreciate how significant it is.

One if the things that always gets me is the EXACT amount of CO₂ pulled from the atmosphere by a plant for it to grow, that I then eat, is the exact amount of CO₂ I then breath out from burning it (unless I use some of that carbon to get fatter, then that is released when one day I am cremated or eaten by bacteria). And the O₂ that is made by the plant growing is also the EXACT amount I need to use to breath to burn that plant and consume it. OK some of that goes in to poop that is used (O₂) and released (CO₂) when that is digested by bacteria. But the CO₂ is the same. It goes around in circles. The circle is complete. It works.

The carbon cycle is all about how carbon moves around in the world. Wikipedia has this the cool image.

So how to stop climate change? - it is so so simple - stop burning old carbon (i.e. fossil fuels).

It is fine to grow trees, make wood, and burn that, the carbon goes round and round.

It is fine to grow food, eat it, and breath out, the carbon goes round and round.

AFAIK cows farting is an issue, as that carbon ends up as methane with has a bigger impact, but AFAIK for less time, and apparently the answer there is feeding the cows seaweed! But generally using carbon to grow food to feed and animal that we then eat and breath out is again OK, carbon goes round and round.

Don't get me wrong, loads of other issues, too many cars and not enough walking and cycling, all sorts, but just looking at climate change, it is all down to the carbon. We'll improve a lot of other stuff by fixing the climate change issues as a side effect!

Almost anything we do with "recently" captured carbon then going to the atmosphere matters not a jot. Pull carbon from atmosphere and release it a year later - not problem. What matters is all that old carbon in fossil fuels being burned. Unless we want an atmosphere that was around a few million years ago, we need to stop.

Even all the "indirect" stuff, like carbon cost of manufacturing and transport, only matter when those processes use fossil fuels directly or indirectly. Make those processes use electricity or hydrogen from green supplies (not from fossil fuels) and they all end up carbon neutral.

The one thing, and this really is the one thing, that matters, is burning old carbon. Stuff pulled from the atmosphere millions of years ago and stuffed in the ground. Burning fossil fuels. That is what matters. That is what needs to stop. It really is as simple as that!

Heck, even making fossil fuels in to plastic which we don't burn, is not an issue! What matters is old carbon going to the atmosphere - STOP IT!

Environmental sensors

For my next little project I am thinking of making a good little environmental sensor box, mainly for CO₂ and temperature as they are the two things I have some control over.

ESP8266 based, why not. But I have been looking at the sensors you can get, and bought a few.

Are all CO₂ sensors crap?

Well, I tried a few, including this CJMCU module (CCS811 based) and this AppliedSensor module.

Sorry to say, but both are crap! And the detail is in the small print - they estimate CO₂ from other sensors, and are very easily confused. I have some isopropyl alcohol and you use that anywhere near them and they quickly say 18000ppm CO₂. Even without such factors they swing wildly all over the place.

It seems you need an NDIR based sensor, and I found this one which seems to actually work! This SCD30 sensor seems to be the business, with CO₂, temperature and humidity (floating point!) via I²C.


Next step - sort a suitable display and box.

I can then use the temperature to control the air-conditioning, and the CO₂ to control extractor fan speed.

Lungs of the Earth

I always heard that the rain forests were "lungs of the Earth" as they use sunlight to convert Carbon Dioxide in to Oxygen which we need to breath. The idea is that they create the Oxygen we all need to live.

And then, more recently, I heard that they are pretty much neutral. Indeed this article points out that the Carbon they extract ends up decomposing and releasing that Carbon Dioxide back in to the atmosphere (using Oxygen in the process). This makes perfect sense and made me wonder why I did not question the "lungs of the Earth" idea in the first place. There are other articles that point out that they will vary absorbing or releasing Carbon Dioxide over periods of years, so a sort of "capacitor" for Carbon Dioxide on the planet, but not the power plant for Oxygen.

So I pondered where does the Oxygen I need to live come from. Well, there is an incredibly simple answer!

The Oxygen I need is used to burn (oxidise) the Carbon from my food. That Carbon in my food ultimately comes from plants (directly, or via other animals). Those plants get the Carbon from Carbon Dioxide in the atmosphere, and using sunlight as an energy source they release Oxygen when they absorb that Carbon. Indeed, the sunlight's energy used to split the Carbon Dioxide, is the energy released when Carbon is burned in my body.

So there is a perfect balance. The exact amount of Oxygen I need in order to burn the Carbon in the food I eat is exactly the amount that was released by the plants that absorbed that Carbon from the atmosphere in order to end up in my food!

Of course, I also end up with some Carbon in my body as part of my body, or leaving my body by other means. That Carbon gets released as Carbon Dioxide when my poop decomposes, and finally when my body decomposes after I die - that decomposition needs exactly the amount of Oxygen that was released by plants that absorbed that Carbon.

So, there should always be exactly enough Oxygen for us to burn the food we eat simply because that food only exists because exactly that much Oxygen was released by photosynthesis in the first place.

Nice isn't it :-)