A circuit of the small inland waterways and canals with stops at the numerous quays is a so-called ‘must do’ for tourists as they say. For municipalities or canal authorities however, it is of great importance to have insight in the water level of these canals to prevent them from flooding. To gain more insight in the water level of the canals, the Ministry of Infrastructure uses sensors with RS232 protocols. Since this technology is quite an old-fashioned one, it is not suited for controlling the water level from several canals real-time from distance.