Hi all, Should anyone face the same problem, I found the root cause: brownout threshold. I burned a new bootloader (Optiboot 8.0) without such trigger and the node has been working with used batteries (~2.7V) since May. Hope this helps.

https://hackaday.io/project/178235-mini-thermometer-hygrometer-with-e-paper-on-nrf5

The product listing for the step-up that the OP is using says: Sucks the juice out of your batteries. Sounds like it delivers on what it promises....

Looks great! Very nice integration with the box you found. Keep up the good work.

@Nca78 said in Particle Powered Air Quality Sensor Logging to Google Docs: @Sebex said in Particle Powered Air Quality Sensor Logging to Google Docs: Perhaps I don't necessarily need to use the same pins Both the sensors you quote are using I2C. So they both use the same 2 pins (SDA, SCL) to communicate. You can put many I2C sensors on those same pins, they each have an address to know which sensor is receiving/sending data to the master (here, your arduino). Look for a tutorial on I2C first. Thanks I get it now

@rvendrame sorry, I did not see your comment. Yes, it is VERY valuable. Thanks a lot

My next issue is the humidity seems to be off. It has read as high as 115% humidity. Is this normal or should I be considering a correction? If so, how would I enter a correction. Its a little odd considering it states that the accuracy is much tighter than that.

@nca78 I don't use ATAES132A. I put it in just in case I wanted to invest some more time using it. I now just use SimpleEncryption, it's secure enough for my purpose atm. (since the area I live in uses KAKU a lot, an insecure 433MHz lightswitch, I don't think anyone would be bothered to hack my temperature sensors. I found 163 433Mhz devices when I left domoticz logging for a couple of days.)

ESUN flex filament used.

@NeverDie Sorry for delay... This is example (improved version with 3d printed fixer)

BTW, I like how you both made a case for it. Very nice!

@gohan said in Arduino Pro Mini Shield for RFM69(H)W: If I remeber right that pin is used as input so the RFM69 is not receiving any 5v signal. In addition there are people claming they have the RFM69 module working on 5v on data pins and 3.3v on vcc, but I hardly suggest to do it. thank you just what i thought . about direct 5v on data...well... i seen a big red sign saying n :DONT do it! lol Level converters are so cheap...that i ordered 5 or 10 thoguether with rfm69 board. sorry about hijack this topic, i though i was on general discussion

Adafruit have a library for the htu21d which works well with Mysensors