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Everyone can participate in environmental data collection and analysis
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Monitor air quality and automatically share the collected data using inexpensive hardware.

OpenWest slides show how to build the project, including slide 24 with wiring explanation.


Install arduino 1.8.2 or newer

Install serial driver from vendor drivers

Set up esp8266 runtime for arduino

Open geothunk.ino in arduino and select board. Tools->Board->NodeMCU 1.0 (ESP-12E Module)

Libraries: sketch->include library->manage libraries

Plug in board and choose the port. On mac: Tools->Port->/dev/cu.SLAB_USBtoUART (Reboot and check your USB cable is a full power+data cable if the port isn't available.)

Hit the upload button.

Reboot the board and use your phone to connect to the Geothunk-XXX access point. In the captive portal screen, set the password for your access point. Hit save. There is a youtube video to show this in practice.

If you're on the same access point as the sensor, you should be able to see graphs for your measurements by clicking its geothunk.local mdns link. If mdns isn't working or you have multiple sensors, point a browser at the IP address displayed on the device instead.

Register and agree to share your data with our agreement


  • Brad Midgley wrote the firmware and built the sensor
  • Tim Harper updated the firmware with refactors, overflow protection, improved sensor listener
  • Dorian Tolman designed the case


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