Detector Systems, Inc.

Diablo Controls, Inc.

Reno a + E

Multisonics, Inc.

Thomas W Seabury

Robert S Allen

Thomas R Potter

Thomas R Potter, Sr

Richard G Freeman

A system of communicating vehicle detection is provided. The system may include a probe having at least a probe controller and a magnetic sensor for detecting the Earth's magnetic fields, and a control system having a main controller, an output port and a two-wire interface for communicating with the probe. The probe controller may be configured to quantify detected magnetic fields into a sensor output value per iteration at a predefined frequency, and initiate an interrupt per iteration the sensor output value is determined to exceed a predefined sensor value. The main controller of the control system may be configured to communicate a supply signal to the probe over a first line of the two-wire interface, monitor a return signal from the probe over a second line of the two-wire interface for interrupts, and generate a call signal on the output port indicative of confirmed vehicle detection if the number of consecutive interrupts in the return signal exceed a predefined interrupt limit.

Vehicle detection two-wire magnetic field sensing probe with communication capability

A technique for operating a vehicle detection system involves obtaining samples randomly from a detector of the vehicle detection system and determining the presence of a vehicle in response to the random samples. When multiple detectors are located in close proximity to each other, the likelihood of interference caused by concurrent sampling events is reduced because of the randomness of the sampling, which in turn reduces the occurrence of incorrect vehicle detection results. Control systems for vehicle detection systems obtain the random samples independently from each other. Because the random samples are obtained independently from each other, multiple inductive loop vehicle detection systems can be operated in close proximity to each other without having to be coordinated or synchronized in any way. The possibility of an incorrect vehicle detection as a result of concurrent sampling events can be further reduced using validity checking techniques.

Non-interfering vehicle detection

A programmable vehicle detector with operator actuatable function selection and parameter value setting keys, and an operational display. A small cluster (four) of key switches enables an operator to select programmable vehicle detector functions, such as pulse/presence, scanning/non-scanning, end of green control; and also adjust the value of settable parameters, such as loop frequency, sensitivity, delay time, and maximum presence time. The value of certain parameters is displayed, either by manual interrogation by operation of the switches during a set mode or automatically during normal operation. During normal operation, the display also indicates dynamically the relative value of the loop inductance, using a unique bar graph, the generation of Call a signal, and the time remaining in a delay time period and a maximum presence time period. The display further indicates which of several channels has been selected for function and parameter programming, or is currently being monitored for operation. The vehicle detector can be operated as both a scanning multi-channel detector or a non-scanning multi-channel detector.

Vehicle detector with operational display

An estimate of the number of vehicles crossing a loop inductor having one or more interconnected discrete loops of the type found in vehicle detector system installations. A measuring signal follows changes in loop inductance caused by the influence of vehicles crossing the loop inductor. A vehicle count threshold value is computed by observing changes in the measuring signal caused by the first car crossing the loop. Subsequent excursions of the measuring signal between relative minima and relative maxima are tested against the threshold and a vehicle count event is registered when the differences exceed the threshold. After a predetermined count period, the number of vehicle counts is estimated from the total count events by multiplying them by an interpolation factor determined empirically from the type of loop inductor. Apparatus for perfoming the method is combined with a conventional vehicle detector system in a switch selectable apparatus for specifying vehicle detector mode or vehicle count mode. The system furhter includes a user selectable circuit for matching the interpolation factor to the type of loop inductor used with the system.

Vehicle detector method for multiple vehicle counting

A method and system for transferring information between a moving vehicle and a stationary information location having a vehicle detector system with a loop antenna by using the loop antenna as either the receiving antenna for signals transmitted from a moving vehicle or as the transmitting antenna for signals generated by a transmitter located at the vehicle detector site for transfer to a receiver mounted on a moving vehicle. The information is encoded on a carrier having a frequency outside the normal frequency range of the vehicle detector system, preferably by interrupted carrier pattern processing.

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Diablo, CA, United States of America

Thomas W Seabury