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Air handling on trains, 1 in a series until I get bored or forget. Full but not rammed Great Northern class 387: 920ppm CO2
in reply to Alexandra Lanes

ooo cool! I've been wanting to take one of my little homemade raspberry pi weather stations to measure the air quality and CO2 on my commute into London. Need to get a USB battery for it 😀 I imagine the CO2 levels on the underground are elevated.
in reply to Charlotte

@Charlotte I got an Aranet 4 since a number of people have had good experiences with them. Battery life is supposed to be pretty good as the display is eink.

My ideal would be a wearable thing that did the measuring and sending to a phone, possibly a pendant that changed colour according to the reading? Challenge is probably power miniaturisation

in reply to Alexandra Lanes

Ooh, I was going to ask what you were using since I've been thinking I should get one, and a humidity sensor would be nice domestically since both the one on my weather station base and remote unit have been stuck at 20% since moving here (or I've got a very dry house)
in reply to Sion [main]

@Sion [main] Does temperature and humidity, logs to phone app by Bluetooth. Dunno if you can read it in other ways.
in reply to Alexandra Lanes

Honestly just the eInk display is enough, but having a temperature/humidity log through the night is appealing.
in reply to Sion [main]

@sparrowsion I think any NDIR COâ‚‚ meter inherently has to measure temperature/humidity/pressure as part of making sense of the IR measurement; but yes I've found the Aranet4's logging of non-COâ‚‚ handy. (Without the phone app; there's good-enough open source code to get at the log.)
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