Irrigation Apparatus and a Sensor Thereof

• US 20130341420A1
• Filed: 12/07/2011
• Published: 12/26/2013
• Est. Priority Date: 12/13/2010
• Status: Abandoned Application

• Current Assignee: Verdirrigation Limited
• Original Assignee: Verdirrigation Limited
• Inventors: Lister, Gary D., Shepherd, Ray, Street, Alvey, Cordingley, Chris
• Application Number:
  US13/994,053
• Publication Number:
  US 20130341420A1
• Time in Patent Office: Days
• US Class Current: 239/1
• CPC Class Codes: A01G 25/167 Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 33/246 for water content

Abstract

The invention relates to a moisture sensor (16) for an irrigation apparatus (10, 100, 118, 121, 130, 140). The moisture sensor (16) being operable to monitor a moisture content for a medium in which it is located to provide a control signal for operating the irrigation apparatus (10, 100, 118, 121, 130, 140) for controlling a water supply (26) to the medium. The moisture sensor (16) comprises a sensing capacitor (46).

Claims

1. A moisture sensor for an irrigation apparatus, the moisture sensor being operable to monitor a moisture content for a medium in which it is located to provide a control signal for operating the irrigation apparatus for controlling a water supply to the medium, the moisture sensor comprising a sensing capacitor, wherein the moisture sensor comprises an oscillator circuit coupled to the sensing capacitor.

12. A moisture sensor according to claim 1, wherein the oscillator circuit comprises an operational amplifier.

13. A moisture sensor according to claim 12, wherein the operational amplifier is operable to charge and discharge the sensing capacitor to provide an output signal from the oscillator circuit having a frequency being dependent on a moisture content of a medium in which the moisture sensor is located.

14. A moisture sensor according to claim 13, wherein a microcontroller is operable to receive the output signal to determine the frequency thereof.

15. A moisture sensor according to claim 1, wherein the oscillator circuit comprises a first semiconductor switch.

16. A moisture sensor according to claim 15, wherein the sensing capacitor is coupled to a modulating capacitor which is chargeable via the first semiconductor switch.

17. A moisture sensor according to claim 16, wherein the oscillator circuit comprises a second semiconductor switch which is operable to alternatively couple the sensing capacitor to a resistor and the modulating capacitor.

18. A moisture sensor according to claim 16, wherein the oscillator circuit comprises an operational amplifier, and the modulating capacitor is coupled to the operational amplifier, such that when a high voltage threshold of the modulating capacitor is reached the operational amplifier has a low voltage output, and when a low voltage threshold of the modulating capacitor is reached the operational amplifier has a high voltage output.

19. A moisture sensor according to claim 18, wherein the operational amplifier is coupled to a pulse counter which is operable to register a count according to the voltage output from the operational amplifier.

20. A moisture sensor according to claim 19, wherein the pulse counter comprises a microcontroller which is operable to determine the frequency of counts.

21. A moisture sensor according to claim 20, wherein the microcontroller is programmable to determine the number of counts over a preset time period to determine the frequency of counts, the preset time period being adjustable.

22. A moisture sensor according to claim 20, wherein the microcontroller has a programmable memory to calibrate the oscillator circuit and/or the sensing capacitor.

23. A moisture sensor according to claim 1, wherein a power source for the oscillator circuit comprises a voltage regulator.

24. A moisture sensor according to claim 1, and further including a buffer amplifier.

26. An irrigation apparatus including a moisture sensor according to claim 1.

2-11. -11. (canceled)

25. (canceled)

27. A method of using a moisture sensor in an irrigation apparatus, the moisture sensor comprising a sensing capacitor, the method including using the sensing capacitor to measure a moisture content for a medium in which the moisture sensor is located to provide a control signal, and operating a water supply to the medium in response to the control signal.

28. A method according to claim 27, wherein the moisture sensor comprises an oscillator circuit coupled to the sensing capacitor, the method including charging and discharging the sensing capacitor using the oscillator circuit to provide an output signal from the oscillator circuit that has a frequency which is dependent on a moisture content of the medium.

29-114. -114. (canceled)