Maybe an iris at the bottom, and vibrating pager motors along the length of the tube, to empty it out? -Randy Glenn E-Mail: PICxpert@yahoo.com Web: http://i.am/PICxpert Currently wondering why I can't get in to Safe Mode - where's a Mac when you need it? -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of John Mullan Sent: Friday, February 18, 2000 7:59 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [PICLIST] [OT] How to measure snowfall or rainfall? OK. Here is another idea. What if you set up some sort of tube that is lined with IR LEDs up one side and IR Detectors on the other, set at precise distances (depending on the resolution desired). If you arranged in a spiral, you could much more finer resolution. Make the tube wide at the top (4-6 inches) and narrower at the bottom (say 1 inch). Once calibrated, should be good. Maybe more elaborate then necessary, but would measure rain or snow. 1/10 of an inch resolution is probably as much as average people need. Somebody have an idea how to empty this contraption after a measurment is made???? John Mullan -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Ken Webster Sent: Friday, February 18, 2000 2:29 AM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [OT] How to measure snowfall? Wagner Lipnharski wrote: >Snow volume is 100% relative to water volume? I guess it is >not 100% the same always. So the same water volume can mean >different volume of snow. Yeah and it would be interesting to measure the ratio. A measure of how dense the snow is. I like it. >Des Bromilow wrote: >> >> How about using Mass measuring techniques? >> The reset function would be accomplished by a heating element >> and some holes inthe bottom of the receptacle, OR maybe you could >> collect the snow, and melt it in one operation, and then use the >> resulting water, (and a standard rain measuring sensor) to >> determine the snowfall. (this , coupled with a therometer, could >> allow the same instrument to measure two things ie: if it's below >> zero celcius, the "rainfall" is snow,if it's above zero degrees, >> then the 'rainfall" is rainfall., how's that for a versatile >> instrument!!!!! Hmm... I wonder how much of the water would evaporate if you just heated the funnel in a rain guage to barely above freezing. I guess that would depend on how cold it was plus the relative humidity plus how fast the snow was falling. I like the idea of letting the snow accumulate first .. then any loss is limited to a shorter time window. >> >>> Randy Glenn 2/18/00 8:42:11 am >>> >> The rainfall thread reminded me of a question I was trying >> to answer: HYow would one electronically measure snowfall, >> in centimetres? I was thinking maybe something to do with >> sonar, or maybe an optical pair (transmitter and receiver >> on opposite sides) that travels vertically? Or, since optical sensors are reasonably cheap, how about a pole with a lot of optical sensors mounted every centimeter. When the snow is up over a sensor it will reflect the light back. If a sensor is above the snow the light will travel outward and not reflect back. One other idea I was toying with is a real-time "is it snowing now?" sensor. One thought I had was to aim a laser at a sensor a good distance away (a hundred feet or so may be nice .. perhaps accomplished by folding the beam back a few times with mirrors) and count how frequently the beam is interrupted to measure snowfall "intensity". Since the sizes of flakes would vary it wouldn't really give you an accurate measurement (centemeters per hour, etc.) but it would at least give a fair estimate. Not that it is all that difficult to just look out the window, but, it would be kind of cool to have a real-time "snow intensity" meter up on my web page just for giggles. Cheers, Ken __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com