Abstract: An apparatus for detecting an object, including a transmitter and an antenna that receives a signal from the transmitter, radiates a transmitted beam of electromagnetic energy, and receives a reflected beam of electromagnetic energy, the reflected beam being a reflection of the transmitted beam when the transmitted beam is reflected from an object. The apparatus further includes a phase detector in communication with the antenna that detects a phase difference between the transmitted beam and the reflected beam, and that produces an output based on the phase difference, and a voltage meter that receives the output and produces a voltage reading.