Abstract: An electronic interface device is provided for use between a sensor and a display unit, including a controllable generator which delivers a signal to the display unit and is connected to an input of a comparator whose other input receives the output signal of the sensor. The output of the comparator controls the up counting or the down counting of an up-down counter of clock pulses. The sign output of the up-down counter controls the generator.

Abstract: A method is provided for displaying the speed and the distance on board a motor vehicle. The shaft of an auxiliary motor drives a speed indicator and a mileage recorder and its rotation controls a train of pulses. The speed of rotation of the auxiliary motor is controlled so that the period of the train of pulses and the total number of pulses are slaved respectively to the period of another train of pulses and to their total number, this other train of pulses being controlled by the rotation of one of the wheels of the vehicle.

Abstract: A probe for measuring the level of a liquid and its method of manufacture are disclosed. A conducting circuit whose resistivity depends on temperature comprises a track applied to a substrate in which is formed a window which leaves free an appreciable length of track, so that its behavior is not disturbed by the presence of the substrate. The conducting circuit is partially immersed in the liquid and the voltage at its terminals is measured when a constant current flows therethrough. The voltage measurement is representative of the level of the liquid.

Abstract: An on board indicator for vehicles is provided, including a sensor detecting a physical magnitude to be indicated, connected to a display device through a low pass filter whose cut off frequency is increased for a given time after switch on of the vehicle, by appropriate circuitry. A threshold detector controlling an alarm device is connected to the output of the low pass filter. Such an indicator may be used for indicating the fuel level in the reservoir of a motor vehicle, for example.

Abstract: A liquid crystal display device is provided comprising a liquid crystal wafer operating by transmission which is disposed in front of a sheet of transparent material having a multitude of parallel opaque flaps substantially perpendicular to the wafer. In daytime use, light rays substantially perpendicular to the wafer pass through the sheet towards the rear of the wafer. For nightime use, the sheet reflects rearwardly of the wafer a part of the light rays coming from a lamp and the flaps stop the other part of these light rays.

Abstract: The present invention provides a probe for measuring the level of a liquid, including a conductor partially immersed in said liquid and whose degree of immersion depends on said variable level to be measured, the resistivity of which conductor depends on the temperature. The conductor is for example etched on an insulating support which is a better conductor of heat than air. The result is a very good linearity for rapid measurements, higher accuracy and a great mounting simplicity.