Automatic moisture measurer for controlled watering of sports ground or garden

摘要

The moisture involves using a tube made of glass or acrylic glass which is inserted into the material. An emission diode generates infra-red waves which are projected via a lens to the material and reflected to a light-sensitive photo-diode. Simultaneously the variation in the absorbtion spectrum due to water, the variation of colour temperature of the measurement material, e.g. darker colour with increased moisture, as well as the variation of the refractive index. These changes are used to measure the moisture level as comparison when moisture free.