The mini-rotary alerts users to material levels in smaller bins and hoppers that contain plastics, food, seed, chemicals, and other powder and bulk solid materials. Its small size and rugged design allows for use of a level sensor where other types of equipment simply will not fit. Its principle of operation is simple: a slow speed motor rotates the paddle when no material is present. When material comes into contact with the paddle, the paddle stops and an alert—such as a light or horn–notifies the operator the bin is full. When the bin is emptied, the paddle begins rotating again. The mini-rotary is simple to install on the side or top of a bin and is appropriate for a variety of light to heavy materials. Paddle options are available, making it adjustable for a wide range of material densities.