Educational activities with Arduino to learn about astronomy

There is a need to promote better science, technology, and mathematics (STEM) education at all school levels. Arduino makes it possible by creating the next generation of STEAM programs that empower students on their learning journey through middle school, high school, and university. These kinds of technologies make it possible to make abstract concepts concrete and manipulable, far from the experience of children and young people, increasing the possibilities of learning. Following the constructionist ideas and practices, the National Institute for Astrophysics has developed play.inaf.it, a web platform that collects various coding, educational robotics, making, and tinkering activities, using astronomy and astrophysics as a tool to develop computational thinking and all the skills that are typical of scientific research in the STEM field. In this paper we want to present two projects created by the Play group. The first one aims to create, using an Arduino board, one LED and a photoresistor, an exhibit capable to describe one of the methods most used to identify exoplanets: the transit method, which exploits the fact that the brightness of a star decreases when the planet passes in front of it, with respect to our line of sight. Thanks to this project it is possible both to know Arduino and understand the information that astronomers can obtain from so-called light curves, such as the orbital period, the size of the planet, etc. The second activity aims to create and turn on one or more constellations using Arduino and some LEDs. In this way it will be possible to describe - through an active, cooperative, and operational approach - what are the stars, the constellations and the close relationship that has linked man to the sky since the dawn of time. Thanks to Arduino it is possible to encourage creativity, allowing everyone to give shape and substance to their ideas because the only limit we can set is our imagination