From: David H. L. Jr. <dh...@dl...> - 2005-12-10 05:17:26
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Yangmin Shen wrote: > Will a magnet on a float inside of a pipe sensed by a reed switch outside > the pipe work? Obviously the pipe would have to be non-magnetic. As long > as the float didn't stick, I would think it would work...heck just oil it! > Or just a with a string around a wheel - sort of like clock chimes, then you either optically or electrically sense how many times the wheel turns. I think Circuit Cellar and Nuts & Volts did some stuff with ultrasonic distance sensors - the ones used on old polaroid autofocuses or new ultrasonic tape measures. Put one near the top of the tank and adjust it to measure to the top of the oil Or put a light sensor in the bottom of a clear tube type level guage (make your own if need be) and measure the light level. Or put a strain gauge under the tank and measure the change in weight. Or set a float on a stick such that it generates switch closures every time it drops another inch. Or user some kind of sensor to detect when the furnace is running and just measure how long it has been on. I suspect the fuel use is fairly constant, I do nto think home furnaces have variable consumption rates. How accurate do you need to be ? How much do you want to spend ? How much time can you put in ? |