Abstract: A device for unlocking a lid provided in a vehicle includes an unlocking actuator unit, a magnetic sensor unit, a signal processing unit, and a controller means. A transmitter unit with a power source generates and transmits a specific magnetic unlocking signal which is received by the magnetic sensor unit, hence, the unlocking actuator is controlled through the signal processing means and the controller means and, hence, the lid is unlocked.

Abstract: A luggage door unlocking device for a vehicle by which a luggage door of vehicle can be unlocked without using an unlocking key is disclosed. The device includes a portable transmitter for generating an unlocking signal, a receiver which is mounted on a vehicle for receiving and discriminating the unlocking signal when the transmitter approaches the receiver and a luggage door unlocking mechanism for operating an unlocking mechanism of the vehicle when the receiver receives the unlocking signal. The transmitter has a walk detector for detecting the periodical vibrations when the person carrying the transmitter is walking which generates a walk detecting signal. Also, a switch turns on or off upon receiving the walk detecting signal from the walk detector.

Abstract: A frequency transmission system comprises a pulse train generator and a signal converter. The pulse train generator generates a pulse signal of a sufficiently short duration in response to oscillation frequency signals, and the signal converter circuit converts the pulse signal into a current signal and blunts the waveform of the converted signal by a capacitor to transmit through power supply lines.

Abstract: A liquid quantity detecting device includes a float-type liquid-quantity meter and a torsion bar-type liquid meter. In the float-type liquid-quantity meter, the liquid quantity is detected by a float in a tank and the position of the float is converted to an electric signal by a variable resistor. The torsion bar-type liquid meter includes housings fixed to the tank, torsion bars, one end of each being fixed to the tank by the housings and the other end of each being fixed to a supporting member so that the torsion bars are twisted by weight of the tank, twisted angle detection means for detecting the twisted angle of the torsion bars, and an electrical processor for supplying a signal corresponding to the quantity of liquid in the tank after receiving a signal from the twisted angle detector. When the liquid quantity in the tank is larger than a predetermined quantity, the liquid quantity, for example, the quantity of gasoline in a gasoline tank, is measured by the floating-type liquid-quantity meter.

Abstract: In a liquid quantity detecting apparatus, a torsion bar is mounted on a stationary structure to support a container thereon in such a manner that the torsion bar is twisted at a torsional angle in dependence upon the weight of liquid stored within the container. An electric detector is provided to electrically detect the torsional angle of the torsion bar so as to generate an output signal indicative of the quantity of the stored liquid based on the detected torsional angle.

Abstract: A liquid level monitoring device includes a casing arranged to be immersed in liquid stored within a container, the casing having first and second ports and being integrally provided with a support member to be attached to the inner wall of the container. A flexible diaphragm is assembled to form first and second chambers in the casing, the first chamber being communicated with the atmospheric air through the first port from which an elongated tube extends into the exterior of the container, and the second chamber permitting the immerse of liquid through the second port thereinto such that an amount of the atmospheric air is compressed within the second chamber in dependence upon an amount of the stored liquid to flex the diaphragm by a pressure difference between the chambers. A pressure transducer is provided to detect the rate of flexure of the diaphragm so as to generate an electric signal indicative of the liquid surface level from a control circuit.

Abstract: A liquid sensor for sensing a level of liquid contained in a tank as well as the presence or absence of water remaining at the bottom of the tank is disclosed. The liquid sensor comprises a housing mounted at the bottom of the tank, a liquid level detecting element mounted on the housing, a pair of electrodes arranged at the bottom of the tank to detect water remaining at the bottom of the tank and an indicator operated in response to signals developed by the liquid level detecting element and the pair of electrodes.