A seismic alarm device for vehicles which is capable of detecting an earthquake while the vehicle is moving and gives the alarm upon occurrence of the earthquake in order to provide the safety such as by stopping the motor vehicle, wherein a plurality of acceleration detectors are mounted on the front and rear of the vehicle or on the left and right sides of the vehicle, output signals generated from these acceleration detectors are fed to a determination circuit, which determination circuit is arranged to measure an amplitude and period of the output signals and to compare phases of the output signals, then to output an alarm signal if the amplitude of the output signals is larger than a predetermined value while their periods are within a predetermined range and no phase difference exists between the output signals of the acceleration detectors, and an alarm circuit gives the alarm when the determination circuit outputs the alarm signal.

Geophones are placed around pipelines to detect third parties, e.g., heavy construction vehicles. Associated computer equipment acquires data from the geophones and discriminates for the frequencies associated with heavy construction vehicles.

A process and device for passive detection of helicopters includes detection of helicopter noise and ambient noise by means of an electro-acoustic transducer, and outputting of an amplitude modulated signal therefrom; amplitude demodulation of the signal in the frequency band between 300 Hz and 3500 Hz; spectral analysis of the demodulated signal; and selection and registration of characteristic frequency lines reflective of the rotary units of the helicopter. The process and device permit passive detection of helicopters in the lower noise, higher frequency band, thereby also permitting utilization of smaller antenna arrays.

The subject invention discloses a conventional method and apparatus for classifying terrestrial moving vehicles in which the seismic signal generated by the vehicle is broken into its Rayleigh and acoustically coupled components. The ratio of the Rayleigh component to the acoustically coupled component is used to classify the vehicle as heavy or light.

A device for controlling a traffic light, where the controlling of the traffic light is dependent upon receipt and recognition of vibrations. The device includes a vibration receiver for detecting vibrations transmitted through the ground, a processor for converting one or more of the vibrations into a control signal and a controller to trigger a traffic light in response to the control signal. The device may also include a vibration generator, e.g., at least one channel or groove in a traffic-bearing surface. The vibration generator preferably facilitates the production of a pattern of vibrations when the tire of a vehicle passes over the vibration generator. Further, the device may include a vibration receiver, capable of detecting a pattern of vibrations and producing a pattern of signals corresponding to said pattern of vibrations.