The SmartBob sensor works like an automated tape measure. Mounted on top of the silo, the sensor drops a weighted cable to the material surface. Upon impact, the cable retracts while counting pulses that are converted to a level measurement. Measurements are programmed to occur at predetermined time intervals to monitor changes in inventory over time. SmartBob has a unique dual compartment design to separate the mechanical and electronic components. To extend service life, the electronics compartment is fully sealed to protect the sensor from dust, debris, and condensation. Mechanical components including the cable and pulley system are housed separately and protected by a wiper that cleans the cable each time it retracts. The housing is Class II rated for hazardous locations.