firmware 'xdata' branch: contains my extensions for
- outdoor node:
- with second BME280 sensor at I²C address 0x76
- first sensor needs to be switched to I²C address 0x77 by connecting SC0 to 3.3V
- all BME sensor data including SDS011 and min/max values provided via http://ip.address/xdata.json
- display node:
- with single BME280 and (LCD) 20x4 characters displaying a single page with values from local and from outdoor node
firmware master branch: 
firmware beta branch: 
The maintained main firmware for the Sensor.Community / Luftdaten.Info Sensor.
A transitional firmware which will look for a firmware file stored on SPIFFS to replace itself with for next reboot or do an endless loop of panic LED blinking if this fails.
This allows to do an Over-the-air (OTA) procedure on setups that have a 1M/3M split layout (rather the more modern 2M/2M) for firmwares larger than 512k (up to ~ 740k).
- BeginnersGuide Beginners guide to ESP programming with Arduino code
- airrohr-.... currently used versions (2017-05-23+)
- airrohr-update-... currently used for OTA (2019-08-30+)
- apiclients clients for the dusti API and other APIs
- arduino native arduino code
- esp8266-lua nodemcu firmware code, lua scripts (not maintained after change to arduino)
- esp8266-arduino programming esp8266 with arduino code/IDE
- r-scripts sensor data analysis with R
- schematics frizzing schematics (not updated, 2016-03-01)
The development is done in the beta branch.