Related: cheap device to track pollution + mesh + visualization: https://luftdaten.info/ https://luftdaten.info/ Once had this thing on a balcony of a shared f

Related: cheap device to track pollution + mesh + visualization: https://luftdaten.info/ https://luftdaten.info/ Once had this thing on a balcony of a shared flat in Heilbronn, Germany. Wondered what that was, previous tenant told me about it and it was never removed from there.