Our environment plays a decisive role in our comfort, our productivity, and our quality of life in general. In Smart Cities, for example, the aim is to optimize the temperature and humidity in buildings for the health of residents and to reduce heating or ventilation costs. At the same time, efforts are being made to achieve more efficient lighting that is better adapted to the workplace, time and seasons. Other factors that play a role are, for example, the concentration of particulate matter in the outside air or the CO2 concentration indoors. Never before have environmental sensors been so important to improve our everyday comfort. As part of the interactive use of environmental sensors, OpenObservatory was developed, which offers a low-cost sensor platform to developers of intelligent systems for smart cities, among others. Both the hardware and software of OpenObservatory are open source, which strives for maximum flexibility for developers. OpenObservatory also has a place in the curriculum of the Industrial Sciences degree program as data source for the Object Oriented Programming course.