Filling rate assessment of recycling containers using ultrasonic transducers

Costs associated with the collection process of recyclable materials can be optimised if the correct prediction of when containers are ready for collection is made. To achieve this, data about the filling rate of containers must be collected. This data gathering is normally done by operators who estimate the filling rate and write it down on a form. An automated sensing system which evaluates the filling rate of containers and transmits it to a database for future analysis can help to improve the efficiency of collection systems. An autonomous wireless sensor used to gather data about the filling rate of containers for recyclable materials, is introduced in this paper. It is based on ultrasonic transducers to assess the filling rate and it uses IEEE 802.15.4 for wireless communications. The sensor sends its data to the collection truck as it approaches the container. This system has been successfully tested in the city of Mirandela in Portugal.