~derf / projects / Wetter
dark mode

Aktuelles Wetter in Dortmund Eichlinghofen; min/max beziehen sich auf die vergangenen 24 Stunden.

Alle Angaben ohne Gewähr.

istminmax
Temperatur (Nord)↘ 19.0 °c16.0 °c44.6 °c
Temperatur (Süd)↘ 17.6 °c16.4 °c39.5 °c
Temperatur (West)↘ 19.7 °c17.6 °c34.5 °c
Luftfeuchtigkeit (Nord)↗ 100 %20 %100 %
Luftfeuchtigkeit (Süd)↑ 99 %28 %100 %
Luftfeuchtigkeit (West)↑ 100 %35 %100 %
Luftdruck 992 hPa991 hPa1000 hPa
Wind↘ 7 km/h0 km/h705 km/h
Niederschlag
PM10 3.5 µg/m³2.7 µg/m³9.9 µg/m³
PM4 3.5 µg/m³2.7 µg/m³9.9 µg/m³
PM2,5 3.5 µg/m³2.7 µg/m³9.9 µg/m³
PM1 3.4 µg/m³2.6 µg/m³9.5 µg/m³
VOC 1.0 1.0 339.0
Licht <10 lx<10 lx>1000 lx

Stand: 20.07.2024 23:30 Uhr

Sensors

  • Bosch BME280: temperature, pressure, humidity via I²C. Firmware: esp8266-bme280-outdoor. Also works like a charm with the Bosch Sensortec BME280 driver e.g. on a Raspberry Pi.
  • TEMT6000: illuminance via ADC. Surprisingly linear, but really only usable for 10lx to 1000lx. Still sufficient to determine whether it is dark, bright, or twilight. Driver and calibration data: esp8266-nodemcu-temt6000.
  • SEN54 (temperature, humidity, particulate matter, volatile organic compounds via I²C). Pricy, but worth it. Driver: esp8266-nodemcu-sen5x.
  • WH1080 anemometer (with reed switch). Wind speed in km/h is number of impulses per second * 2.4; IIRC it's one or two impulses per revolution.

No longer in service:

  • Maxim MAX44009 (illuminance via I²C) (max44009.py) – corrosion damage; replacements were too pricy. Driver: esp8266-nodemcu-max44009.
  • NOVA SDS011 (PM2,5 and PM10 fine dust particles via UART) – worked fine, but SEN54 is just better. Needs post-processing when used in high humidity environments, e.g. during fog or rain. I haven't implemented that yet. Driver: esp8266-nodemcu-sds011.
  • TFA Dostmann 30x3161 (tipping bucket rain gauge / Regenwippe with reed switch) – causes spurious interrupts on the corresponding ESP8266 pin; debugging tbd. One impulse per 0.45mm (i.e., one impulse per 0.45l/m²)

Meta

Data collection is managed by four solar-powered ESP8266 boards.

Main station

Power supply comes from a solar-charged 12V lead acid battery and is converted to 5V for two ESP8266 boards. One is responsible for wind and rain measurement, the other one is connected to the SEN54. Both are awake and connected to Wi-Fi continuously. Originally, this whole ensemble used to be controlled by a Raspberry Pi 3.

nowminmax
Buck Converter↘ 27.9 °c22.3 °c40.5 °c
Battery (Süd) 12.9 V12.6 V14.4 V

Secondary Temperature and Humidity sensors

The boards are powered from individual 500mV solar cells and BQ25570 harvesters, and automatically adjust their duty cycle to keep battery voltage between 3.7 and 4.1 V. The BME280 is turned off while the ESP8266 is in deep sleep. Source code: bme280 harvester.lua

nowminmax
Battery (Nord) 4.03 V4.03 V4.04 V
Battery (West) 4.12 V4.08 V4.13 V