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US 6,288,979 B1Granted
Solar-driven eternity clock
AssigneeMoneray International Ltd.
InventorJoseph Tak Ming Kwok
Life of this patent
Estimating the term…
Abstract
An electronic eternity clock is powered by solar cells. The LCD segment display is shut down during the night by the use of a sensing circuit utilizing sampling pulses from an associated microcontroller which turns a transistor on and off which is connected to a floating ground between the solar cell and an isolating diode, both series connected across the rechargeable battery.
Claims3
An electronic clock comprising:
- a rechargeable battery having common and positive terminals;
- liquid crystal display means having segments for indicating the time for said clock;
- microcontroller means connected to and powered from said positive terminal responsive to timing pulses including means for driving said segments and including means for generating sampling pulses;
- a solar cell and a diode series connected therewith across said terminals for charging said battery and powering said microcontroller means during conditions greater than a minimum predetermined level of ambient light impinging on said solar cell;
- voltage level sensing means for sensing a voltage level at a point between said diode and solar cell and responsive to said sampling pulses from said microcontroller means for turning off said segment driving means if said voltage level is below a predetermined threshold.
2 more elements
Dependencies are inferred from the claim text.