last updated: 27/04/18
In Stuttgart/Germany there exists the OK Lab Stuttgart. There goal is to promote transparency development, open data and citizen science. There project luftdaten.info helps to measure fine dust with cheap but performant self-built sensors. Luftdaten.info generates a continuously updated particular matter map from the transmitted data. Fine dust becomes visible.
Most infos can be found on luftdaten.info.
In our mini workshop in Luxembourg we will build sensors with a WeMos D1 mini board (ESP8266).
Here is the LINK to our PDF in Luxemburgish.
The cable that comes with the dust sensor is split in half and soldered to the Wemos board. In our workshop this is already done.
|SDS011 Pin1||TX||⇨||Wemos D1|
|SDS011 Pin2||RX||⇨||Wemos D2|
|SDS011 Pin3||GND||⇨||Wemos GND|
|SDS011 Pin5||5V||⇨||Wemos 5V|
|DHT22 Pin1||3V||⇨||Wemos 3V3|
|DHT22 Pin2||DATA OUT||⇨||Wemos D7|
|DHT22 (Pin4)||GND||⇨||Wemos GND|
The other pins are not connected. As we use a temperature sensor witch is soldered to a breakout PCB, we have only 3 pins. One cable is not connected!
Now we will connect the tube, the dust sensor and the temperature sensor.
!!Pay attention to turn the DHT22 header the right way (GND to -)!!
Next fit the tube to the dust sensor.
In our next step we stick the dust sensor in one of the two elbows and plug the lid (stick the tube through the 8 mm hole). The power supply cable goes through the second elbow and is connected to the Wemos board (Micro USB).
Close the open end of the second elbow with a net or similar, so that the air can circulate but insects stay outside.
Connect the station with the power cable. The sensor opens an access point with a name (SSID) witch is has 2 parts. The name "Feinstaubsensor-" followed by the sensor ID (here 7224851).
!!Remember that number, as we need it later!!
Connect to this access point. Wait a moment until the connection is made. Sometimes it take multiple attempts.
Open your browser and type in http://192.168.4.1/. You see the menu site and are able to type the SSID and the Password of your WiFi network.
After saving, the sensor will restart (and has no longer an AP). If everything is setup correctly, after about 10 minutes visit the following site:
Search for your ID (in the example above the 7224851) and view the dust sensor (SDS011) or the temperature sensor (DHT).
If you want to access your sensor homepage, search for his IP address by logging in to your router and type this IP in your browser.
To make the sensor part of the sensor network (map), send an email
email@example.com with these information:
More infos on luftdaten.info.
Start Arduino, open
File > Preferences and enter the string
Additional Board Manager URLs field. Open Boards Manager from
Tools > Boards > Board manager..., scroll down and install esp8266 platform. Select Wemos D1 mini Pro from
Tools > Board after installation and select the right port.
The sensor software is on github (opendata-stuttgart/sensors-software) and is named airrohr-firmware. All the libraries named in the document must be installed to get the software running.
The simpler way is to use my reduced software (Downloads). Here we need:
Sketch > Include Library > Manage Libraries.... Use the filter function to find the library and install it.
Compile and program your Wemos :).