JPS5496086A - Wireless sensor - Google Patents

Abstract

PURPOSE: To achieve a wireless design in a simple constitution by solving problems of battery, etc. operating in the vicinity of 100°C, by providing a device to apply the movement of liquid enclosed in a cylinder by a piston and the movement of the piston to a piezo-electric element.

CONSTITUTION: An electrode 10 consists of a disc part enclosed by two piezo- electric elements 8, 9 reversed in the direction of polarization, and a subsequent slender part 11. The part 11 projects through the upper bottom or an ignition part 6 and is bent in the form of U. A pointed needles part 1 is pierced into meat or other foodstuff. When the foodstuff is heated, glycerol 3 expands due to the heat to push up a piston 4. If the temperature remains below the set temperature (a), an inverting spring 7 droops down. When the expansion continues, a magnet 5 pushes up the spring 7 to set in an inverted state (b). At this time, the spring 7 strikes the element 8 to generate a high voltage in the electrode 10. The voltage is discharged at the tip of the part 11, thereby emitting electric waves. By receiving the waves, it is judged that the foodstuff has reached the set temperature, so that the temperature sensor may be realized in wireless design.

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