| CPC A01G 27/003 (2013.01) [A01G 27/001 (2013.01); A01G 27/008 (2013.01); F25B 21/02 (2013.01); F25B 2321/0212 (2013.01)] | 19 Claims |
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1. An automatic plant watering device comprising:
at least one thermoelectric module with a hot face and a cold face,
at least one power supply connected to energize the thermoelectric module providing sufficient power to produce a heat flow in the thermoelectric module to reduce a temperature of the cold face below 32 degrees F.,
at least one first heat sink thermally connected to the hot face,
at least one air moving device arranged to provide a flow of air over at least a portion of the at least one first heat sink,
at least one second heat sink thermally connected to the cold face,
at least one container filled with a liquid and having thermally conducting walls thermally connected to the second heat sink, with at least one of said walls exposed to ambient air, the container being configured to allow a temperature of the at least one exposed wall to reduce below 32 degrees F. when the thermoelectric module is energized, and the liquid having a freezing temperature sufficiently below 32 degrees F. so as to maintain a liquid state while said thermoelectric module is energized,
at least one water collection chamber positioned below the at least one exposed wall of the container and configured to hold collected melt water from said at least one exposed wall of the container until a temperature of said collected melt water has risen a desired amount above 32 degrees F.,
at least one soil moisture sensor probe, and at least one controller configured to control the energization of the at least one thermoelectric module, upon receipt of a signal from the at least one soil moisture sensor probe indicating a level below a desired moisture content of a soil surrounding a plant, for a period of time in excess of an hour to cause the temperature of the at least one exposed wall of the at least one liquid container to be maintained below 32 degrees F. during said period of time, so as to cause a build-up of frost on said at least one exposed wall and thereafter to deenergize the at least one thermoelectric module to permit the temperature of said at least one exposed wall to rise towards ambient temperature.
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