Abstract: An engine temperature monitoring device for alerting a vehicle operator that an engine is overheated includes a heat sensor adapted for detecting ambient temperature levels. A processor adapted for monitoring the temperature levels is operational coupled to the heat sensor. A speaker for producing an audible sound is operationally coupled to the processor. The speaker is turned on when the heat sensor detects a temperature of the engine which is greater than an acceptable tolerance. A power supply is operationally coupled to the processor. The heat sensor is secured to the engine such that the heat sensor may detect the temperature of the engine.

Abstract: An alarm device for signaling when an object reaches a specified condition. The alarm device includes a sensor for detecting the condition of the object. The device further includes a switch element which is closed when the sensor indicates the specified condition. The closed switch element triggers an alarm which will signal a person monitoring the condition that the specified condition has been reached.

Abstract: A system and apparatus for detecting and evaluating surface conditions on a road surface and atmospheric conditions simultaneously from a vehicle is disclosed. The system comprises a sensor for detecting the presence of deposited material on a road surface, a detector for determining one or more characteristics of the deposited material such as freezing temperature, process means for converting a detected signal and display means for displaying the condition of the road surface, and a sensor for detecting falling precipitation. An embodiment of the present invention includes a remote sensing apparatus which utilizes electromagnetic radiation to sense actual surface material conditions, temperatures, and composition and local atmospheric conditions at the vehicle as it is moving over a travel surface. This information is then processed through a computer in order to determine those additional steps necessary to apply additional materials to the road surface in order to minimize hazardous driving conditions.

Abstract: A temperature tag and system for sensing and reporting an internal temperature reading inside a container. The temperature tag mounts on an outside surface of the container, and a shaft with a temperature sensor extends through the side of the container and senses the internal temperature reading. A plurality of readings may be recorded at a predefined sampling rate and stored in a data memory. The temperature tag then sends the temperature readings to a reader device that presents the temperature readings to a user. The reader device may trigger the temperature tag to send the temperature readings with a signal such as an infrared (IR) signal, a radio frequency (RF) signal, and the like. The temperature readings may be analyzed in the temperature tag, the reader device, or may be downloaded to a computer to determine if an alarm condition exists.

Abstract: In a method for determining the state of a road during driving of a motor vehicle, the sound which is generated when a vehicle tire rolls on an underlying surface is sensed. A frequency signal is determined by means of a sound level signal which describes the sound, and is divided into at least two sub-zones by means of at least one limiting frequency. The sub-zones are each assigned to an associated frequency band, and an intensity value is determined for each of at least two frequency bands from the assigned sub-zone of the frequency signal. The intensity value is characteristic of the sound intensity which is present in a frequency band. An intensity ratio is formed from two intensity values by dividing the first intensity value of the first frequency band by the second intensity value of the second frequency band, and is used to determine the state of a road.

Abstract: A heat source locator (10) is disclosed having an elongated housing (11) in which is mounted a thermal detector (21), an infrared laser (22), a visible laser (23), and a light bar (25) all coupled directly or indirectly to the outputs of a semi-conductor (27). The thermal detector (21) is mounted within the housing (11) to sense a thermal input within a field of view FV along a central longitudinal axis LA. The infrared laser (22) is mounted within the housing (11) to transmit an infrared laser beam IRB generally parallel to and closely adjacent the longitudinal axis LA. The visible light (23) is mounted within the housing (11) to transmit a visible light laser beam VB generally parallel to and closely adjacent the longitudinal axis LA. With this construction, a target may be generally located by the thermal detector and the location pinpointed through an illumination of the target by one of the lasers.

Abstract: A method for monitoring thermal overload of an electric load element in a motor vehicle containing other electric consumers, which can be switched into a stand-by phase is disclosed. The load element is monitored by a control device using a calculated load temperature parameter. During a first operational phase, a power loss of the load element or a quantity that is essentially proportional thereto is evaluated for calculating the load temperature parameter. During one or more stand-by phases, the control device is switched with essentially no current between the first operational phase and a second operational phase. After the control device is switched on in the second operational phase, at least one quantity, which is characteristic for the moment of switching on, is evaluated for calculating the existing load temperature parameter.

Abstract: A fuel cell system includes a fuel cell stack with single fuel cells stacked together in a fuel cell housing and a detection system for fire or elevated temperatures. The detection system may include a monitoring system; a sensor unit that detects fire or elevated temperatures inside said fuel cell housing; and a voltage or current source.

Abstract: A method of signaling for a change of an air filter of a vehicle air conditioning system is disclosed. The present invention uses a sensor installed in a conventional air conditioner and the appropriate time for changing the air filter is determined by checking compressor operation when a degree of airflow is decreased during air conditioner operation.

Abstract: An electrical wiring monitoring system for sensing overheating of electrical lines which could result in electrical fires. The electrical wiring monitoring system includes a housing member having front and side walls and being adapted to be mounted to a wall structure near a fuse box; and also includes a cover member being hingedly attached to the housing member and being closeable over the front wall of the housing member; and further includes a monitor assembly including a microprocessor being disposed in the housing member, and also including a power source being connected to the microprocessor, and further including an alarm-sounding assembly being connected to the microprocessor, and also including an electrical line control/display assembly being connected to the microprocessor; and also includes wire overheating detection members being connected to the microprocessor and being attached about electrical wires of electrical lines.

Abstract: Apparatus and a method of operating any structural configuration of a heater and array of temperature sensors to measure with high accuracy, the level of stratified liquids like water and oil or water and gasoline and non-stratified liquids, liquid temperature, and other liquid properties and detect ice formation on aircraft surfaces. Thin and narrow strips of dissimilar material will be used for the heater, array of temperature sensors, mount, and coating. The connecting wires to and from the apparatus will be from the same material. Simultaneous measurements from all the temperature sensors, before and after heat is applied, will be used to generate accurate temperature profiles for the entire configuration and not just from two adjacent temperature sensors. Different features of the temperature profiles will determine accurately the liquid level, liquid temperature and other liquid properties. Apparatus of the invention may also be used to detect ice formation.

Abstract: A fuel cell system includes a fuel cell stack with single fuel cells stacked together in a fuel cell housing and a detection system for fire or elevated temperatures. The detection system may include a monitoring system; a sensor unit that detects fire or elevated temperatures inside said fuel cell housing; and a voltage or current source.

Abstract: A method of fabricating various models of fire detectors only from a limited number of common parts or unit in accordance with user's specific needs but at a reduced cost. The method utilizes a smoke sensor unit (1), a thermal sensor unit (2), a signal processing unit (3), a signal transmission unit (4), and a power unit (5), and then combines at least one of the smoke sensor unit and the thermal sensor unit with the power unit and optionally with at least one of the signal processing unit and the signal transmission unit.

Abstract: A system and apparatus for detecting and evaluating surface conditions on a road surface and atmospheric conditions simultaneously from a moving vehicle as disclosed. The system comprises a sensor for detecting the presence of deposited material on a road surface, a detector for determining one or more characteristics of the deposited material such as its freezing temperature, process means for converting a detected signal and display means for displaying the condition of the road surface, and a sensor for detecting falling precipitation. An embodiment of the present invention includes a remote sensing apparatus which utilizes electromagnetic radiation to sense actual surface material conditions, temperatures, and composition and local atmospheric conditions at the vehicle as it is moving over a travel surface.

Abstract: A system and apparatus for detecting and evaluating surface conditions on a road surface and atmospheric conditions simultaneously from a moving vehicle. The system comprises a sensor for detecting the presence of deposited material on a road surface, a detector for determining one or more characteristics of the deposited material such as its freezing temperature, process means for converting a detected signal and display means for displaying the condition of the road surface, and a sensor for detecting falling precipitation. An embodiment of the present invention includes a remote sensing apparatus which utilizes electromagnetic radiation to sense actual surface material conditions, temperatures, and composition and local atmospheric conditions at the vehicle as it is moving over a travel surface.

Abstract: An ice detector has a pair of probes, each of which is used for determining the accretion of ice thereon. One of the probes in the assembly is configured so the smaller droplets of supercoooled water are inertially separated and flow away from the one probe. The ice accretion on the one probe is primarily from large (50 microns or greater) supercooled droplets. The ice accreting on the one probe is therefore biased to supercooled large droplets. The probes are connected to detection circuitry that will determine the ratio of the rates of icing between the probes so the presence of supercooled large droplets can be determined. In one form, a flow guide is arranged to create an airflow that carries smaller droplets past one of the probes without impinging on the probe, but the higher inertia, supercooled large droplets will impinge on that one probe.

Abstract: A device for indicating ice formation (and/or already existing ice) on a surface (6) of an object using a sensor (2) comprising a temperature difference measuring device, preferably a Peltier element (4), that has one of its contact surfaces (5) in thermal contact with the surface (6) which is exposed to ice formation. Ice formation is detected through measurement of the change in heat flow which occurs at the contact surface (5) due to the heat released in connection with ice formation, which measurement is carried out by connecting a voltage indicator to the connecting lines (11, 12) of the Peltier element. After having established that ice has formed, these wires can, if the sensor (2) is a Peltier element (4), be connected to a current source (13) for alternate heating and temperature sensoring of said contact surface (5), whereby the surface temperature will remain 0° C.

Abstract: A microcomputer is connected to a detect circuit for an out-of-phase electric source, a flow switch for a cooling liquid, a refrigerant high pressure switch, a refrigerant low pressure switch, a pump overload protector, a compressor overload protector, an abnormal detect circuit for an oil temperature sensor, an abnormal detect circuit for a room temperature sensor, an abnormal detect circuit for a temperature detection, a timing circuit for an air filter net, a timing circuit for a cooling liquid filter, and a voice electric circuit electrically

Abstract: The present invention relates to the effective searching system for searching the criminals fleeing at large or straying persons, wherein the utilizing media provided with the information to specify the individual is used to send the personal information concerning the above said utilizing media and the terminal information concerning the terminal using the said utilizing media to the searching center from the utilizing system side of the utilizing media through the sending means so that the controlling means at the above said searching center records the personal information which has been sent, and the utilized information of the utilizing media corresponding to the individual on the basis of the terminal information onto the recording measures for management, thus providing for the search for the place of the utilizing media which has been used and identifying the final place of use of the utilizing media as a wanted spot when searching for the person who has used the said utilizing media, where the area o

Abstract: An ice detector for an aircraft comprises a strut and probe assembly, and it is positioned on the aircraft so that the pressure field around the ice detector causes a lower temperature region on the probe assembly compared to the aircraft. Ice will therefore form on the probe assembly before it forms on the aircraft to provide an early warning of icing conditions near freezing temperatures.

Abstract: The present invention pertains to an ice detector particularly adapted to detect the presence of water droplets capable of forming supercooled large droplet (“SLD”) icing on aircraft surfaces. The invention takes advantage of boundary layer flow patterns adjacent to the detector, and their effect on water droplets, to provide a signal indicative of SLD icing conditions when they exist. The detector is also capable of distinguishing between the presence of water droplets that cause traditional cloud icing and SLD icing.

Abstract: The device according to the invention provides a non-contacting temperature sensing device incorporating micro-bolometric detectors as the suitable infrared sensors for automotive applications. A first and second infrared sensors each include an active infrared sensing element and a temperature drift compensating element. A current bias is applied to the active infrared sensing element as well as to the temperature drift compensating element, which is identical in structure with the active infrared sensing element, and the voltage outputs of these two elements pass through a differential amplifier. The fluctuation in the substrate temperature or the ambient temperature affects the active sensing element and the compensating element in the same way, thus it is cancelled out. Instead of using one spectral band of the infrared radiation, as in the prior art, two spectral bands are used resulting in a first and second signal generated by the first and second infrared sensors.

Abstract: A method and system of collecting data concerning thermal properties of roads and using the collected data to form a geographic database that can be used in a vehicle safety system to implement a safety process when the vehicle approaches a location of a potential ice hazard. Data indicative of the thermal properties of roads are collected by driving along roads in a vehicle equipped with equipment that senses thermal properties of the roads upon which the vehicle is being driven. Using the collected data, a geographic database is formed that relates positions along roads to thermal properties of the roads at the positions.

Abstract: An optical device on board an aircraft for detecting icing conditions including an optical beam emitter to create at least one illuminated external volume of measurement through which there circulates a flow of air charged with water particles; a collector optical system for the collection of at least a part of the light beam back-scattered by the water particles (the external volume of measurement being located on the optical axis of said collector optical system); a photodetector for detecting back-scattered optical beams; a signal processor for processing the signal delivered by the photodetector to compute the severity of the icing conditions; an information provider for providing information on the calculated severity of the icing conditions. Advantageously, the optical means for the differentiation of device includes a differentiation for differentiating between liquid water particles and solid water particles, based on analysis of the polarization.

Abstract: An installation for melting of snow or ice, e.g. at roof downpipes on flat roofs, in gutters and the like, comprising a heating means (11), a temperature sensor means (4,6) and a control unit (1) for connecting and disconnecting the heating means (11) in dependence on sensed temperature. The temperature sensor means comprises a first temperature sensor (4) for sensing the surface temperature at the place of snow or ice melting, and a second temperature sensor (6) for sensing the air temperature at the topical place.

Abstract: A vehicle exterior object detector apparatus includes a transmitter and receiver carried within a housing and mounted by a holder to a support on the vehicle. A heater element is carried in the holder in surrounding relationship with one end of the transmitter and receiver housing for melting ice and snow build up on the end of the housing for proper operation of the transmitter and receiver.

Abstract: An apparatus for carbon monoxide detection and automatic shutoff of a heating system is provided which includes a single housing containing a thermostat, a carbon monoxide detector, and a control circuit serially connected to the heating system via the existing thermostat wiring connections. The control circuit includes a relay with a plurality of contacts which are opened and closed to automatically control the operation of the furnace based on the operation of the carbon monoxide detector. In another embodiment, an existing thermostat is retrofitted by mounting the existing thermostat on an adapter plate containing an integrated carbon monoxide detector and control circuit. Another embodiment of the invention includes a carbon monoxide detector, a transmitter serially connected to the carbon monoxide detector for transmitting a predetermined radio frequency, and a receiver serially connected to the existing combustion-type furnace system for receiving the predetermined radio frequency from the transmitter.

Abstract: An apparatus for detecting ice forming conditions includes a substrate having a first surface and a second surface; a sensor disposed on the first surface, the sensor being made of a material having a characteristic which varies in a known manner with respect to temperature; and a unit for monitoring the characteristic and for detecting ice forming conditions from the characteristic. A method for positioning the apparatus to detect ice forming conditions, to detect the presence of ice, and to determine an ice accretion rate is also provided.

Abstract: An icing sensor utilizes a surface gap transmission line along which a radio frequency is transmitted. The phase delay of the radio frequency along the transmission line is dependent upon the dielectric constant presented at the surface in the gap between the transmission line electrodes. Accordingly, changes of dielectric constant affect phase delay of the transmitted frequency. This phase delay may be used to detect the difference between ice, water and snow as well as the presence of freezing point depressing fluids such as ethylene glycol. When the sensor is mounted on an aircraft control surface, the presence and likelihood of icing conditions may be predicted. Through the use of one or more temperature, freezing point depressing fluids/water mixture determined from dielectric constant, and rate of change of the dielectric constant, it is possible to predict the time delay until icing begins. Thus, the sensor of the present application may safely reduce the effort and expense in aircraft deicing.

Abstract: A freeze protection system for a car wash facility having a plurality of bays and having exposed water lines located in an area that is subjected to freezing temperatures. By using a temperature probe connected via a digital temperature meter to a microprocessor, the system will only operate when the temperature is lower than a pre-set value and will shut off when the temperature is higher than a pre-set value. When activated, a predetermined charge of antifreeze mist will purge the piping in each bay, leaving only a small residual of antifreeze. When a bay is used, the system is reactivated, purging only the bay that has been used. The system is easily adaptable to any number of bays or areas of piping that must be protected.

Abstract: A system and apparatus for detecting and evaluating surface conditions on a road surface from a moving vehicle as disclosed. The system comprises a sensor means for detecting the presence of deposited material on a road surface, detecting means for determining one or more characteristics of the material such as its freezing temperature, process means for converting a detected signal and display means for displaying the condition of the road surface. A first embodiment of the invention includes a collection device for collecting a sample of the surface materials and one or more sensors to detect the freezing point of the material. A second embodiment includes a collection chamber which can be isolated and its contents frozen so that the freeze temperature may be obtained irrespective of knowing the composition of the material.

Abstract: There is disclosed an apparatus for freeze prevention protecting an irrigation system. The response of the apparatus depends on environmental conditions. At a first temperature condition, the irrigation system is shut down. At a lower temperature condition, the system remains shut down and heat is delivered to the above ground portions of the system. In the event temperatures continue to decrease, a full drainage of the above ground portion of the irrigation system will be accomplished and alarm notification will be given.

Abstract: A system and apparatus for detecting and evaluating surface conditions on a road surface from a moving vehicle as disclosed. The system comprises a sensor means for detecting the presence of deposited material on a road surface, detecting means for determining one or more characteristics of the material such as its freezing temperature, process means for converting a detected signal and display means for displaying the condition of the road surface. A first embodiment of the invention includes a collection device for collecting a sample of the surface materials and one or more sensors to detect the freezing point of the material. A second embodiment includes a collection chamber which can be isolated and its contents frozen so that the freeze temperature may be obtained irrespective of knowing the composition of the material.

Abstract: An ice detector and deicing fluid effectiveness monitoring system for an aircraft is disclosed. The ice detection portion is particularly suited for use in flight to notify the flight crew of an accumulation of ice on an aircraft lifting and control surfaces, or helicopter rotors, whereas the deicing fluid effectiveness monitoring portion is particularly suited for use on the ground to notify the flight crew of the possible loss of the effectiveness of the deicing fluid. The ice detection portion comprises a temperature sensor and a parallel arrangement of electrodes whose coefficient of coupling is indicative of the formation of the ice, as well as the thickness of the formed ice. The fluid effectiveness monitoring portion comprises a temperature sensor and an ionic-conduction cell array that measures the conductivity of the deicing fluid which is indicative of its concentration and, thus, its freezing point.

Abstract: An apparatus for detecting ice includes a heat flow sensor which senses the rate of flow of heat through a member. At the same time, the temperature differential across the member is determined. Based on the temperature differential, it is possible to calculate a theoretical heat flow rate based on the assumption that there is no ice on the member. If ice is present on the surface of the member, the actual heat flow rate will be significantly less than the calculated or theoretical heat flow rate. It is contemplated that the apparatus and method of this invention will be particularly useful in conjunction with the detecting of the presence of ice on a wing of an aircraft.

Abstract: A paging receiver having alerting means implemented as a speaker and a light emitting diode (LED). The paging receiver has a decoder for outputting a pair of periodically varying drive signals on determining that a call meant for the receiver has been received, a speaker drive for causing a speaker to sound in the pattern of either one of two drive pattern signals, and an LED driver for turning on the LED in the other pattern. The drive periods of the two drive pattern signals are arranged alternately with each other and such that they do not overlap each other, whereby the luminance of the LED is maintained at a sufficiently high level even when a battery powering the paging receiver reaches the last stage of its service life.

Abstract: A display is provided for indicating changes between first and second operating conditions in an appliance such as a clothes dryer. A sensing circuit senses changes in operating conditions within the appliance. A heater is connected to the sensing circuit and is responsive to various signals produced by the sensing circuit to generate heat. An elongated thermally conductive substrate is mounted adjacent to the heater for receiving and conducting thermal energy produced by the heater. A layer of thermochromic material overlies the substrate and is capable of changing colors in response to changes in the temperature of the conductive substrate.

Abstract: A method for measuring and adjusting the temperature of surface ice in artificial ice rinks, in which water is frozen to ice with the aid of refrigerating channels arranged in the rink and through which refrigerant is passed a by means of a refrigerating system and wherein the temperature of the ice is controlled by controlling the refrigerating power of the refrigerating system. The method is mainly characterized in that the surface ice temperature is measured with the aid of at least one sensor, which functions to measure infrared radiation from the surface ice. The signals produced by the sensor are processed in a control unit which controls the refrigeration system in a manner to bring the surface ice to a predetermined temperature. The invention also related to an arrangement for carrying out the method.

Abstract: A moisture sensor with two heatable concentric moisture electrodes and a temperature sensor detecting the electrode temperature is set into the roadway surface to be monitored. The moisture electrodes are heated by a heating current circuit. The heating current circuit is connected to a computer which has a store for storing device-specific parameters, desired values and a processing program. During each measuring cycle the computer processes the temperatures of the moisture electrodes measured by the temperature sensor and a signal which is representative of the surface moisture. A control signal is produced therefrom which heats the moisture electrodes. An alarm or switching signal is produced when the moisture electrodes have reached a temperature characteristic of the formation of ice and a conductivity indicative of moisture is present between the moisture electrodes.

Abstract: A warning system for vehicles detects actual road surface temperature and advises the driver of surface temperatures which indicate the vehicle may be approaching possible ice formation on roadways. The warning system comprises an infrared detector mounted externally on the vehicle and aimed at the road surface, the detector arranged to read only the infrared temperature wavelength emissions associated with concrete and asphalt to eliminate confusing and erroneous readings inadvertently received through infrared emission from other objects in the vicinity. The detector is connected to a processing unit which translates the electric signals from the detector into a temperature readout display for the driver and the processing unit may include an alarm which is activated to attract the driver's attention when road temperatures are detected that are below a set minimum temperature that is selected by the driver's manual adjustment of a temperature select control knob on the unit.

Abstract: The present invention utilizes a single temperature sensor and heating element in thermal contact with the sensing surface. The signal from the temperature sensor and the signal from the heating element are input to a standard microprocessor integrated circuit. The microprocessor continuously compares the two signals to accurately assess whether snow is present on the sensing surface. The present invention eliminates the requirement for a moving airmass to accurately assess the presence of snow on the sensing surface. The present invention does not ingest snow nor require ice formation to operate. The snow sensing surface and the sensor housing are weather and debris resistant. The present invention may be mounted in an elevated position or in any suitable location proximate an area to be monitored. The present invention serves as an integral part of a closed loop control system for numerous snow removal applications.

Abstract: Method and apparatus for detecting icing, particularly on airfoils such as helicopter rotor blades, by detecting warming caused by latent heat released as water freezes. The sensors may be multiple or single, contact or remote.

Abstract: A detector system for detecting the formation of ice on an aircraft outer surface, e.g. wing skin. The ice detector system utilizes a light source, light detector and temperature sensor coupled together for providing signals representative of icing which may be utilized to provide an alarm to the cockpit of the aircraft. Built In Test Equipment (BITE) is also included in the detector system for system failure indication to the pilot of the aircraft.

Abstract: An ice detector circuit controls heating of a probe detecting ice. The circuit generates an icing output as a function of a temperature output generated by the probe. A control circuit cyclically controls a start time of the heating. A time measurement circuit measures a warm-up time to a first temperature threshold below the melting temperature, and measuring a melting time to a second temperature above the melting temperature. A comparator compares the melting time to a stored comparison parameter adjusted by the warm-up time and provides the icing output.

Abstract: A deicing system for an aircraft engine (4) having blades (14, 16) fixedly attached to rotating propulsors (6, 8) has emitters (22, 28) which irradiate microwave beams (24, 26, 30 32) onto coatings (18, 20) which are fixedly attached to said blades (14, 16). Substantially more of the energy of the beams (24, 26, 30, 32) is absorbed by the coatings (18, 20) than by any water or ice on the blades (14, 16) causing any ice which is on the blades (14, 16) to be thrown off by the centrifugal force of the rotating propulsors (6, 8).

Abstract: An ice detector probe senses an ice deposition from an air mass flowing relative to the probe. The probe includes a support for installation of the probe to receive the airflow and an element formed on a substrate having a sensing surface which directly receives the airflow. The element heats the sensing surface to melt an ice deposition formed thereon. The resistance element also senses the sensing surface temperature during heating and provides an output representative of such temperature.

Abstract: An ice detector circuit for sensing an ice deposition on a sensing surface of an ice detector probe from an air mass flowing relative to the probe. The probe includes a heater to heat the sensing surface and a temperature sensor for sensing the sensing surface temperature during heating. The temperature sensor provides the circuit with an output having a level varying as a function of the sensing surface temperature. The circuit includes a controller which selectively energizes the heater, a timer which provides a timing output representative of a time interval elapsed between selected temperature sensor output levels, and computing means, such as a microprocessor, which computes an output representative of ice deposition as a function of a predetermined relationship between ice deposition and the timing output.

Abstract: A method and apparatus for advance warning signaling to a motorist of an ice condition on a driving surface. The method steps include mounting a plurality of traffic signalling devices along a driving surface for sensing the prevailing temperatures and thereby continuously signal a motor vehicle operator of the changes in temperature as he approaches a driving surface subject to freezing to permit him to take any necessary precautionary corrective action in driving the motor vehicle. The signalling devices utilize thermostat elements for sensing a narrow temperature range adjacent the freezing temperature and provide visible signals, preferably two colors for signalling a warm or nonhazardous temperature, a cold temperature signalling a frozen driving surface or a combination or mixture of the colored signals to permit the motor vehicle operator to be warned, in advance, as he approaches a driving surface that is becoming colder, leading to a stretch of a driving surface that may be frozen.

Abstract: An ice detector comprises first and second simultaneously electrically energized resistors one of which is in good thermal contact with the surface where the presence or absence of ice is to be detected and the other of which is thermally insulated from that surface. When ice is present on that surface there will be a different between the temperatures, and hence the resistances, of the two resistors, which difference, when sensed, indicates the existence of ice.

Abstract: Ice formation on an aircraft surface swept of an air flow is detected by using an electrical heater which produces a small limited amount of heat to, on the one hand a heat flow meter and, on the other hand to a heat sink. When there is no ice on the transducer it produces a large output signal but when ice forms on the transducer the ice, due to its high resistance to heat flow, causes a change in balance between the two heat flows and a change in output of the heat flow measuring transducer.