Here is my latest
monitAir Raspberry Pi device
It’s designed to be mobile or fixed, it doesn’t matter other than the power source.
Now forgive me for no fancy formatting, but I’m on my phone for the pictures.
Just before the lid goes on and power up
All unpacked ready to get squeezed in
It is a tight squeeze as the SDS011 is almost the size of the 80x80 IP55 box.
But it goes in,
The GNSS module is placed just behind the SDS011 as there is room.
The Pi ZeroW just happens to bolt on to SDS011 nicely, it has my preferred vibration reduction standoffs™*
Everything is removable, I was going to solder everything up to PP points (usb), GPIO points and remove and make it more compact, but this just makes it easier to change and fix.
Speedfit/polypipe tube is used at the bottom, cutting off the 14mm entry point. This keeps it in place, tight and waterproof. An o-ring or similar could be used to stop it from being pulled out, there seems no need here.
The BME280 is slipped down the tube, this will be fed air that comes in the SDS and must pass the exhaust down the tube and out.
Possibly with reduced humidity, I don’t know.
But the values may be compared to an outside source and calibration compensation adjustments made (this is how it normally done in say a phone or other cases.)
I’m not so worried about these results, it’s more to pick up humidity readings.
That’s about it, it running python3 software at boot, timestamps are created from the gnss, which is especially useful for a Pi device as it doesn’t keep time itself at reboot but uses a last known time.
So time should always be accurate
I hope it keeps working I’m buying some 2m USB cables for a stationary device power, it can then go on walls etc
*They are actually little rubber terminal protectors found on a brand of PP3 battery, could be Duracell Industrial?