'been a bit wet lately, and wondered about having a rain sensor in teh system. There seem to be three types available, any of which might do the job (see below), with various obvious pros & cons. Anyone tried one, by any chance ?
Rain sensors ... for irrigation systems are available in both wireless & hard-wired versions, most employing hygroscopic disks that swell in the presence of rain & shrink ... again as they dry-out - an electrical switch is in-turn depressed or released ... some ... use tipping bucket or conductance type probes to measure rainfall ...
Nowadays, rain sensors are integrated in a system to automatically start the windscreen wipers ... the most common rain sensor implementation is based on the principle of total internal reflection: an infrared light is beamed at a 45-degree angle into the windshield from the inside, near the lower edge - if the glass is wet, less light makes it back to the sensor, and the wipers turn on.
Rain sensors ... for irrigation systems are available in both wireless & hard-wired versions, most employing hygroscopic disks that swell in the presence of rain & shrink ... again as they dry-out - an electrical switch is in-turn depressed or released ... some ... use tipping bucket or conductance type probes to measure rainfall ...
Nowadays, rain sensors are integrated in a system to automatically start the windscreen wipers ... the most common rain sensor implementation is based on the principle of total internal reflection: an infrared light is beamed at a 45-degree angle into the windshield from the inside, near the lower edge - if the glass is wet, less light makes it back to the sensor, and the wipers turn on.
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