The economical and compact Mini-Rotary is designed for controlling material levels in smaller bins and hoppers that contain plastics, food, seed, chemicals, and other powder and bulk solid materials. Its small size, yet 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. Then, when material comes into contact with the paddle, the paddle stops and an alert, such as a light or horn, will notify the operator the bin is full. When the bin is emptied, the paddle again begins to rotate, alerting the operator that a refill is necessary.