Motion sensors
First Claim
1. A motion sensor device comprising a dielectric liquid between conductors and arranged such that movement of the liquid causes a change in capacitance between the conductors, and a circuit which is operable to generate a signal indicative of movement in response to a capacitance change exceeding a predetermined threshold occurring within a predetermined interval.
1 Assignment
0 Petitions
Accused Products
Abstract
A motion sensor device comprises a conductive cap fixed to one layer of a printed circuit board to define a volume half of which is filled with a dielectric liquid. A conductive layer on the opposite side of the printed circuit board forms with the cap a capacitor, the capacitance of which is dependent upon the location of the liquid within the cap. A motion signal is generated in response to a change of capacitance from that presented in any static orientation of the device, so long as the capacitance change exceeds a threshold and occurs within a predetermined interval.
18 Citations
13 Claims
- 1. A motion sensor device comprising a dielectric liquid between conductors and arranged such that movement of the liquid causes a change in capacitance between the conductors, and a circuit which is operable to generate a signal indicative of movement in response to a capacitance change exceeding a predetermined threshold occurring within a predetermined interval.
- 2. A motion sensor device comprising a sensor formed of a printed circuit board and cap mounted thereon so as to form an enclosed volume which is partially filled with a dielectric liquid, the printed circuit board having a conductive layer which, together with a conductive part of the cap, forms a capacitor, the capacitance of which varies in response to movement of the liquid, the capacitance being dependent upon the orientation of the sensor, the device further comprising a circuit for generating a movement-indicating signal in response to a change of the capacitance from that presented in any static orientation.
Specification