SENSOR DEVICE FOR INTERRUPTING IRRIGATION

1 . A method for controlling irrigation comprising:

generating an indication representing the amount of rain fall at a sensor unit;

transmitting a signal comprising at least the indication from the sensor unit to an interface unit, wherein the interface unit is adapted to cause an interruption of programmed watering schedules of an irrigation controller and wherein the interface unit is separate from the irrigation controller;

receiving the signal at the interface unit;

receiving user input relating to the interruption of the programmed watering schedules of the irrigation controller via a user interface integrated with the interface unit, wherein the user input defines a rain interruption threshold;

determining, at the interface unit, based at least on the indication from the signal and the user input, whether irrigation should be interrupted; and

generating an interrupt command to interrupt irrigation in the event it is determined that the irrigation should be interrupted.

2 . The method of claim 1 , wherein the determining whether irrigation should be interrupted step comprises processing the signal and determining if a relationship exists between a first threshold and the indication at the interface unit; and

wherein the generating the interrupt command step comprises generating the interrupt command to interrupt irrigation if the relationship exists.

3 . The method of claim 1 , wherein transmitting the signal step comprises:

receiving a request for the indication from the interface unit; and

transmitting the signal comprising at least the indication in response to the request.

4 . The method of claim 1 , further comprising generating an indication of a temperature at the sensor unit, wherein the transmitting the signal step further comprises transmitting said indication of temperature.

5 . The method of claim 4 , wherein the determining step further comprises determining, based at least on the rate of change in temperature whether the irrigation should be interrupted.

6 . The method of claim 4 , wherein the determining step further comprises determining, based at least on the current temperature whether the irrigation should be interrupted.

7 . The method of claim 4 , further comprising processing the indication to determine whether there is a change in the temperature, wherein transmitting the signal comprises transmitting the signal when a change in the temperature is detected.

8 . The method of claim 4 , further comprising processing the indication at the sensor unit, comprising:

determining at the sensor unit whether a relationship exists between at least the indication of temperature and a local threshold; and

entering a low temperature operational mode at the sensor unit when the relationship exists;

wherein the signal comprises at least a low temperature message.

9 . The method of claim 8 , wherein entering a low temperature operational mode comprises reducing the frequency of generating the indication and transmitting the signal.

10 . The method of claim 4 , wherein determining whether irrigation should be interrupted step further comprises processing the signal and determining whether a relationship exists between the indication of temperature and a threshold; and

wherein the generating the interrupt command step further comprises generating the interrupt command interrupting irrigation if the relationship exists.

11 . The method of claim 1 , wherein the determining step further comprises determining, based at least on a rate of rain fall whether the irrigation should be interrupted, the irrigation not in an interrupted state when the determining is performed.

12 . The method of claim 1 , wherein the determining step further comprises determining, based at least on the total amount of rainfall whether the irrigation should be interrupted.

13 . The method of claim 1 , further comprising processing the indication to determine whether there is a change in the amount of rain fall; and

wherein transmitting the signal comprises transmitting the signal when the change in the amount of rain fall is detected.

14 . The method of claim 1 , wherein the transmitting the signal step comprises transmitting the signal wirelessly to the interface unit.

15 . The method of claim 1 , further comprising sending a request for the signal from the interface unit to the sensor unit.

16 . The method of claim 1 , wherein the transmitting the signal step comprises transmitting the signal periodically.

17 . The method of claim 1 , wherein the signal further comprises an indication of a signal strength of signals received at the sensor unit that were transmitted by the interface unit and a battery strength of the sensor unit.

18 . The method of claim 1 , wherein the transmitting step comprises transmitting the signal over a two-way communication link; and

wherein the receiving step comprises receiving the signal over the two-way communication link.

19 . A system for controlling irrigation comprising:

an interface unit comprising:

an input unit adapted to receive a signal from a sensor unit, the signal comprising an indication representing an amount of rain fall at the sensor unit;

a user interface integrated with the interface unit, the user interface being adapted to receive user input relating to interruption of irrigation executed by an irrigation controller, wherein the user input defines a rain interruption threshold and wherein the interface unit is separate from the irrigation controller; and

a controller coupled to the input unit adapted to process the signal to determine based at least on the indication from the signal and the user input, whether the irrigation executed by the irrigation controller should be interrupted and to generate an interrupt command to cause the interruption of the irrigation in the event it is determined that the irrigation should be interrupted; and

the sensor unit comprises:

a sensor adapted to output the indication representing the amount of rain fall; and

an output unit adapted to output the signal comprising at least the indication.

20 . The system of claim 19 , wherein the sensor unit further comprises a second input unit adapted to receive the request from the interface unit and output the signal in response to the request.