Vehicle Loop Detector

Vehicle detector  principle vehicle detector is the use of LC oscillator to detect whether there are metal objects at the coil to achieve the detection of the vehicle. Vehicle detector has a fixed capacitance, and then in the ground around a 3-5 m long coil, when the coil is not the vehicle when the inductance is relatively low, LC oscillation frequency is relatively high, the frequency is greater than 50Hz, when the coil has Vehicle, the inductance increased sharply, the frequency of lower-end LC oscillation, this time the frequency is less than 50Hz. Vehicle detector can be based on the frequency of LC oscillation to determine whether there is a vehicle through. In this case, Vehicle detectors are commonly used in parking lot systems. A, Vehicle detectors are used in conjunction with the barrier, and the B vehicle detector is used in conjunction with an automatic card reader. In this case, When the vehicle detector and the barrier with the use of vehicles at this time detector ...

How Loop Detectors Work A frequently asked question in the newsgroups is about how the vehicle detectors used in traffic lights and in car parks work. The author designed such a detector too many years ago for comfort and has frequently posted replies to these questions. Here is one of those replies. It is not a definitive treatment of the subject but should give you an overview of how loop detectors work. When you approach a traffic signal or car park boom gate, you may notice a rectangular "scar" where the road surface has been cut with a saw and then re-sealed. This is the sensor loop. The loop consists of several turns or wire buried in the roadway and connected to an electronic circuit which can detect a car passing over it. Normally the loop is about 1m x 1.5m in size. How do the electronics detect the passage of the vehicle over the loop? There are three methods I know of: "Damped Oscillator" The loop is part of an oscillator circuit. The oscillato...