Citizen science can be explained as the engagement by nonprofessional scientists in collecting data, analyzing data, developing technologies and the publication of these on a voluntary basis. In a majority of citizen science projects the data to be collected is geospatial and is being presented on maps. If the data is about environmental observations, this approach is often referred to as participatory sensing. A novel approach in this field is to equip citizens with DIY-environmental sensor stations and to establish citizen driven sensor networks. This approach leads to better data coverage but also contains motivational aspects, as citizens build up their own devices. Most existing DIY sensor stations are not fully open in terms of source code, data collection, hardware, educational documents or extensibility for other platforms. That's why they lack transparency for the user, e.g. for scientists, who are interested in the data or citizens who want to understand the algorithms. The SenseBox project started at the Institute for Geoinformatics, University of M?nster, and is an ongoing open citizen science project. Based on open hardware components (Arduino microcontrollers and compatible sensors) citizens build their own Internet of Things enabled sensor stations to collect environmental data (temperature, humidity, air pressure, loudness, VIS-light, UV-light). The data is being published as open data and visualized on a web based platform, the OpenSenseMap (OSeM). An educational edition of the SenseBox and didactical material are being introduced into high schools, where students learn to code, measure environmental phenomena and work scientifically. The whole source code is open source, instructions are being published as open educational resources (OER) and models for a 3D-printed waterproof case are available as open source as well. In a first project phase, around 50 SenseBox stations were deployed to citizens and schools in Germany. Some participants had problems in the building and registration process of the SenseBox, others disconnected their SenseBox after some time. In this paper we want to investigate, if usability problems were the cause of the low success rate and how the motivation of citizen scientist can be preserved to ensure long-term data collection. In a user study we plan to evaluate the workflow of (a) building up the SenseBox station, (b) register it on OSeM and (c) verify the communication. Therefore we invite non professionals to our institute for an observed usability study in a controlled environment. A number of ten attendees is sufficient to improve usability significantly. As a basis, the current state of our online tutorials, containing text documents with illustrations and examples, are provided to the participants. Sessions are video recorded, and participants are being interviewed afterwards. In a next step, the results are analyzed to enhance project documentation and hardware design to a more user friendly version. The enhanced construction kits are being rolled out and provided to a new group of citizen scientists. In a final step, a questionnaire is used as an evaluation for the user study and the motivation of the participants.