[PIC] How to measure level of liquids and sense relativehumidity?
Mark Willis email (remove spam text)
Laser could be aimed at say 30 degrees from vertical onto the waters'
surface, a sensor at 30 degrees the other side of vertical would pick up
specular reflection, BUT:
Water's top surface isn't perfectly flat so you get early "hits",
perhaps want several photodiodes and to think on how to handle the top
surface wave problem there. If you have a top styrofoam "float" atop
the water, stick a reflective mylar sheet on there and you have specular
reflection again, and reduce the wave problem <G>
There are capacitive sensors used to detect water levels also.
What's wrong with a cheap and easy, hot bead thermistor solution,
though? Constant current through a thermistor to intentionally
self-heat it to say body temperature or so, when in free air - then
measure the resulting voltage - when water level rises to where the
thermistor is covered in water, it'll cool the thermistor in a heck of a
hurry, thus voltage change and you know the water's there. Want the
water to not spray onto the thermistor, of course, placing the
thermistor inside a tube or if needed adding a tank water inlet baffle
will solve that though <G> Yeah, it's contact sensing, I know.
Hugo Jorge M|ller wrote:
See also: www.piclist.com/techref/microchip/devices.htm?key=pic
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