Flow Detection Systems alert users if the flow status of a bin has changed or communication is interrupted. This system consists of a remote sensor probe mounted in either a pneumatic pipeline, gravity chute or feeder, and a control console mounted in an area accessible to users. A non-intrusive sensor senses flow / no-flow conditions using Doppler technology. It works by transmitting a low energy signal through a Teflon process seal into the material flow stream. A portion of the signal is reflected back to the sensor, with the movement of material causing a frequency shift called the Doppler Shift, which is used by the sensor to detect material flow.