| 摘要 |
A Christmas tree ornament uses a water sensor that provides on demand an indication by light and/or sound if the tree needs water. A portion of the ornament contains a funnel side which allows water to be added to the tree. The other portion of the ornament contains the circuitry for the sensor. A sensor, in the form of a pair of electrodes or terminals, connected to the circuitry, is contained in the water of the Christmas tree stand. The circuitry further includes a battery, an on/off switch, a resistor, a green LED, and a red LED mounted on a display panel. In operation, when the switch is turned on, the green light is energized indicating that the battery is good (a safety feature). If the red light is not on, it is an indication the tree needs water. Water can be added through a funnel side of the ornament. When the electrodes are immersed in the water, a circuit is completed and the red light turns on to indicate sufficient water for the tree.
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