Moisture sensing device
US4837499A · kind A · utility
27Cited by
41References
9Claims
0Family size
Inventor
Key dates
| Filing date | May 19, 1986 |
| Grant date | Jun 6, 1989 |
| Priority date | — |
| Expiry date | May 19, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A moisture sensing device for an irrigation system is disclosed. A pair of concentrically disposed cylindrical conductors are separated by a fibrous material, such that a capacitor is formed whose resistance will vary in response to the level of moisture present in the fibrous material. An electrical circuit is connected across the cylindrical conductors for measuring the variable resistance caused by the level of moisture present in the fibrous material. If the soil is dry enough to require watering, the sensor circuit will produce an output signal to the appropriate solenoid in the irrigation system to permit watering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.