Metal Detector Sensor

A metal detector is defined as an electronic instrument used to detect the presence of metal nearby. Metal detectors are widely used for finding metal inclusions hidden within objects, or metal objects buried underground. This metal detector module basically consists of a handheld unit with a sensor probe that swept over the ground or other objects. If a piece of metal comes in the sensor range, indicated by a changing tone in earphones, or a needle moving on an indicator. When a target is detected the metal detector generates an audible response, such as a beep or change in tone. Basically, the device gives some indication of distance; which means the closer the metal is, the higher the tone in the earphone or the higher the needle goes.

Metal detectors work by transmitting an electromagnetic field from the search coil into the ground. As a result, any metal objects (targets) within the electromagnetic field become energized and retransmit an electromagnetic field of their own. The retransmitted field is received by the detector’s search coil alerts the user by producing a target response. Certain metal detectors can be set to ignore unwanted targets and discriminate between different target types. . The control box in the device contains the detector’s electronics. This is where the transmit signal is generated and the received signal is processed and converted into a target response.

There exist certain cases when unwanted targets are attracted to a detector, normally ferrous (attracted to a magnet), such as nails, but also be non-ferrous, such as bottle tops. If the metal detector is set to reject unwanted targets then a target response is not produced for those targets. The detecting range of the metal detector is “as deep as the diameter of the coil”. So detectors with larger coils will detect deeper. However, detection depth also depends upon detector methods and other environmental factors.