Micro power water leak detector

Abstract

A fluid sensing system and approach having a leak sensor. The leak sensor may output a signal when a fluid is detected. The signal may go to an alarm circuit which can sound a warning or alert. The signal may also go to a control interface of a piece of equipment, such as a water heater, to shut off the piece equipment in an event that it is causing a leak of fluid. Also, the sensing system may have a low battery sensor and indicator in case a battery supplying power for the sensing system is running low. The sensing system may be made of analog circuitry and discrete components.

What is claimed is: 
     
         1 . A water sensing system comprising:
 a water heater control module connected to a water heater;   a water leak detector connected to the water heater control module;   a battery pack;   a battery voltage sensor connected to the battery pack;   a boost module connected to the water leak detector and the battery voltage sensor;   an alarm module connected to the boost module; and   a low battery indicator connected to the battery voltage sensor; and   wherein:   the water leak detector uses electrical conductivity through water for water detection; and   the water leak detector continuously detects water in real time.   
     
     
         2 . The system of  claim 1 , wherein the boost module comprises:
 a timer connected to the water leak detector;   a signal generator connected to the timer; and   a voltage converter connected to the timer.   
     
     
         3 . The system of  claim 2 , wherein the alarm module comprises:
 an alarm driver connected to the voltage converter; and   an alarm connected to the alarm driver.   
     
     
         4 . The system of  claim 2 , wherein the water leak detector, the water heater control module; the battery voltage sensor, the boost module, and the alarm module are analog circuits. 
     
     
         5 . The system of  claim 1 , wherein the water leak detector comprises a sensing cable to cover an area sensed for water. 
     
     
         6 . The system of  claim 5 , wherein when the water leak detector senses water, one or more actions that occur are from a group comprising:
 a signal from the water leak detector that goes to the water heater control module to shut down the water heater in the area sensed for water; and   a signal from the water leak detector that goes to the alarm module to sound an alarm indicating that water has been sensed by the water leak detector.   
     
     
         7 . The system of  claim 1 , wherein when the battery voltage sensor indicates a voltage that is less than a predetermined voltage, then the battery voltage sensor sends a signal to the low battery indicator that reveals a voltage condition of the battery pack. 
     
     
         8 . The system of  claim 6 , wherein:
 the water leak detector has a capability to sense water and provide the signal to the water heater control module to shut down the water heater, and provide the signal to the alarm module to sound the alarm; and   the capability has a duration of ten years or more on a set of initially fresh batteries in the battery pack, or a duration until water is sensed by the water leak detector, whichever duration is shorter.   
     
     
         9 . A fluid leak detector comprising:
 a liquid leak sensor;   a liquid heater control module connected to the liquid leak sensor;   a timer connected to the liquid leak sensor; and   an alarm module connected to the timer.   
     
     
         10 . The detector of  claim 9 , where in the alarm module comprises:
 a signal generator connected to the timer;   a voltage boost converter connected to the signal generator; and   an alarm circuit connected to the voltage boost converter.   
     
     
         11 . The detector of  claim 10 , wherein the alarm circuit comprises:
 a piezo driver connected to the voltage boost converter; and   a piezo alarm connected to the piezo driver.   
     
     
         12 . The detector of  claim 10 , further comprising a battery power module connected to the liquid leak sensor, the liquid heater control module, the timer, the signal generator, the voltage boost converter and the alarm circuit. 
     
     
         13 . The detector of  claim 12 , wherein the liquid leak sensor has two conductive points that, upon being connected via a liquid, have a change of impedance between the two conductive points so as to cause a first transistor circuit to provide a liquid conduction signal to the liquid heater control module and the timer. 
     
     
         14 . The detector of  claim 13 , wherein the signal generator provides a pulse width modulated (PWM) signal to the voltage boost converter. 
     
     
         15 . The detector of  claim 14 , wherein:
 the liquid conduction signal to the liquid heater control module shuts off a liquid heater; and   the liquid conduction signal to the timer results in the signal generator outputting the PWM signal used to convert a first voltage from the battery power module to a second voltage via the voltage boost converter.   
     
     
         16 . The detector of  claim 15 , wherein:
 the second voltage from the voltage boost converter goes to a piezo driver; and   a piezo alarm is energized by the piezo driver.   
     
     
         17 . The detector of  claim 15 , wherein, in an event of the battery power module having the first voltage below a predetermined voltage, a low battery sensing circuit causes a second transistor circuit to connect the second voltage from the voltage boost converter to a low battery voltage indicator. 
     
     
         18 . A method for detecting leaks from a water heater, comprising:
 connecting a water leak sensor to a water heater control module and a timer;   detecting whether there is water leakage from or around a water heater; and   powering the water leak sensor, the water heater control module, and the timer with a first voltage from a battery set; and   wherein:   if there is water leakage detected from the water heater, then the water heater control module shuts off the water heater and the timer is started;   the timer starts a pulse width modulated (PWM) signal generator;   the PWM signal generator drives a boost converter that converts the first voltage to a second voltage; and   the second voltage drives an alarm circuit.   
     
     
         19 . The method of  claim 18 , wherein:
 the alarm circuit is connected to the water leak sensor; and   the alarm circuit sounds when there is water leakage detected by the water leak sensor from or around the water heater.   
     
     
         20 . The method of  claim 18 , further comprising:
 connecting a low battery sensing device to the timer; and   wherein:   if a low battery condition is detected by the low battery sensing device, in which the first voltage of the battery drops to or below a pre-determined threshold voltage, a low battery warning signal is provided by the low battery sensing device; and   an indicator circuit is provided the low battery warning signal by the low battery sensing device to reveal a low battery warning.