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Andreas Kahler edited this page Nov 3, 2019 · 7 revisions

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CitizenSensor is a device for measuring nitrate in soil. The CitizenSensor device is OpenSource and can be built by citizen scientists themselves. The CitizenSensor device enables hobby gardeners and other interested citizens to measure nitrate in a way that was previously only possible in the laboratory.

CitizenSensor Nitrate Measurement System

The CitizenSensor project consists of the following components:

  • RaspberryPi-HAT: A printed circuit board attached on top for the Rasbperry Pi with measuring electronics for electrochemical measurements.

  • RaspberryPi Software: Software that interactively guides the user through the steps of nitrate measurement, automatically performing electrochemical measurements.

  • Electrometer: A circuit for amplifying electrochemical measurements.

  • ConnectorBoard: A plug-in board for the connection of peripheral devices.

  • Enclosure: The 3D data of the CitizenSensor housing for the production of a 3D print.

  • Dokumentation: Documentation for the CitizenSensor project, as well as instructions for nitrate measurement in the soil.


The CitizenSensor project is a cooperation of Fraunhofer EMFT (Facility for Microsystems and Solid State Technologies) and FabLab Munich. The project was funded in 2018/2019 by the BMBF (Federal Ministry of Education and Research).

The project had two objectives:

  1. Testing the cooperation of researchers and citizen scientists from the maker environment within the scope of a concrete project.

  2. Development of an OpenSource device for the electro-chemical measurement of nitrate in soil.


The measuring method of the CitizenSensor is based on electro-chemical measurement. Within the scope of the project, the technical basics for electro-chemical measurement were developed.

The CitizenSensor device is based on the Raspberry Pi microcontroller and extends it with special measuring electronics for electro-chemical measurements.

The design of the RasperryPi-HAT is such that any electro-chemical measurement is possible. In particular, the design also supports measurements using cyclovoltammetry.