초록 ▼

In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the pos

In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station. The device may also be used to determine if an object that it is affixed to has been moved, such as for a theft alarm for an object such as a painting. In a second aspect of the invention, a gravitational sensor is used to monitor the gravitational field of the earth and determine if an associated object or person has been moved with respect to the gravitational field, thus providing motion detection and signaling an alarm.

대표청구항 ▼

In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the pos

In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station. The device may also be used to determine if an object that it is affixed to has been moved, such as for a theft alarm for an object such as a painting. In a second aspect of the invention, a gravitational sensor is used to monitor the gravitational field of the earth and determine if an associated object or person has been moved with respect to the gravitational field, thus providing motion detection and signaling an alarm. or —OCF2—,a is 0, 1 or 2,b is 1 or 2, andL1, L2and L3are each, independently of one another, H, F or Cl.2. A liquid-crystalline compound according to claim 1, wherein R1is a straight-chain alkyl radical having from 1 to 10 carbon atoms or an alkenyl radical having from 2 to 10 carbon atoms.3. A liquid-crystalline compound according to claim 1, wherein a+b=1 or 2.4. A liquid-crystalline compound according to claim 2, wherein a+b=1 or 2.5. A liquid-crystalline compound according to claim 1, wherein L1is fluorine and L2is fluorine or hydrogen.6. A liquid-crystalline compound according to claim 2, wherein L1is fluorine and L2is fluorine or hydrogen.7. A liquid-crystalline compound according to claim 3, wherein L1is fluorine and L2is fluorine or hydrogen.8. A liquid-crystalline compound according to claim 5, wherein L2and L3are fluorine.9. A liquid-crystalline compound of claim 1, which is of one of the formulae I1 to I94:in which R1is as defined inclaim 1 and (F) is fluoro or hydrogen.10. A liquid-crystalline medium comprising at least two mesogenic compounds, wherein at least one compound is of the formula I according to claim 1.11. An electro-optical liquid-crystal display containing a liquid-crystalline, medium according to claim 10.12. A compound of claim 1, wherein a=o.13. A compound of claim 1, wherein one of Z1and Z2is —CF2O— or —OCF2— and the other is a single bond.14. A liquid-crystalline medium of claim 10, which exhibits a nematic phase range from −20° C. to above 100° C., a dielectric anisotropy, &Dgr;&egr;, ≧4.15. A liquid-crystalline medium of claim 10, wherein the proportion of compounds of the formula I is from 5-95% by weight.16. A compound of claim 1, wherein R1is ethyl or propyl.