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It sounds like you are looking for something like the air monitor I have been developing over the last two years. It is about the size of a deck of cards and f

It sounds like you are looking for something like the air monitor I have been developing over the last two years. It is about the size of a deck of cards and fits in a shirt pocket. The Lithium Polymer battery powers it for 12-16 hours and is recharged with USB-C. It uses a high-accuracy CO2 sensor (±(40 ppm + 5 %) and you can manually calibrate it to 420 PPM outdoor air. A key innovation is reporting via a dynanmic QR code on its 128x64 OLED display. Just point your phone camera at the QR code and it takes you to a site showing a report with graphs and data tables of recent measurements. There is no app to install or web site to log into. The web page is context-free and all of the measurement data is in the query string. It is nearly ready for production and likely to sell in the $150 price range.

christiangenco 4y ago
Link?
- HTresearch 4y ago
  No link yet. Still working on a web site for it.
  - christiangenco 4y ago
    When you've got one I'd love to link to it from gen.co/air!
BetterGeiger 4y ago
Sounds interesting! If I may ask out of curiosity: Why OLED? Why this QR thing and not Bluetooth, or is it both? Is it storing long-term data or just while battery is on?
- HTresearch 4y ago
  OLED is the cheapest display with enough resolution. No Bluetooth. A previous version had it, but the development effort was much higher, given it then needed an App also. I wanted something simple for say a school teacher to report values in their classroom. Data is not stored long term currently. Just since last power on.
TeMPOraL 4y ago
That sounds neat, and I love the idea of displaying a QR code, even though I'm not sure how practical it would be. Is it there to allow viewing more data than would otherwise fit on the display in human-readable form? For my use case, I could hack a system with a spare phone reading the code on a timer and uploading the results, but this feels like an overkill. How much more complex would it have to be to use that same USB-C charging port for data and power delivery? I'm imagining attaching an ESP32 board to it, which would be powered by your device, and would occasionally wake up, read a CSV file or a data stream over that USB connection, upload it to my home server, and go back into deep sleep. With an option to turn the OLED display off, I imagine it could even extend the battery life. (Please don't take this as criticism - I fully understand my use case is most likely out of scope of your project, but I'm wondering how close it is to be supported.)
mdp2021 4y ago
I hope you can also do without the QR code, and directly display the URL... Also, that the basic data can be seen directly on the display.
- HTresearch 4y ago
  The current readings are on the display. The QR code encodes 40 previous values of CO2 plus 40 of the VOC index. I have a debug mode that can display the whole URL, but it is so long that it would be impractical to type it in instead of the simple QR scan.

christiangenco 4y ago

Link?

HTresearch 4y ago
No link yet. Still working on a web site for it.
- christiangenco 4y ago
  When you've got one I'd love to link to it from gen.co/air!

BetterGeiger 4y ago

Sounds interesting! If I may ask out of curiosity: Why OLED? Why this QR thing and not Bluetooth, or is it both? Is it storing long-term data or just while battery is on?

HTresearch 4y ago
OLED is the cheapest display with enough resolution. No Bluetooth. A previous version had it, but the development effort was much higher, given it then needed an App also. I wanted something simple for say a school teacher to report values in their classroom. Data is not stored long term currently. Just since last power on.

TeMPOraL 4y ago

That sounds neat, and I love the idea of displaying a QR code, even though I'm not sure how practical it would be. Is it there to allow viewing more data than would otherwise fit on the display in human-readable form? For my use case, I could hack a system with a spare phone reading the code on a timer and uploading the results, but this feels like an overkill. How much more complex would it have to be to use that same USB-C charging port for data and power delivery? I'm imagining attaching an ESP32 board to it, which would be powered by your device, and would occasionally wake up, read a CSV file or a data stream over that USB connection, upload it to my home server, and go back into deep sleep. With an option to turn the OLED display off, I imagine it could even extend the battery life. (Please don't take this as criticism - I fully understand my use case is most likely out of scope of your project, but I'm wondering how close it is to be supported.)

mdp2021 4y ago

I hope you can also do without the QR code, and directly display the URL... Also, that the basic data can be seen directly on the display.

HTresearch 4y ago
The current readings are on the display. The QR code encodes 40 previous values of CO2 plus 40 of the VOC index. I have a debug mode that can display the whole URL, but it is so long that it would be impractical to type it in instead of the simple QR scan.