Weather Station Hardware > Oregon Scientific Hardware

'Cheap' Rain Collector Heater - Ideas - Plans - Tests

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Sam and all,
  Here are the photos I took today of my unit:

Thermostat unit to turn on and off the heater at pre-determined temperature.

Nice job and pics, I will post mine up, once I get the camera downloaded.  I got company coming tomorrow, so I need to go clean the fish tank, and cycle some water.

Mine is not as fancy as the one done very well and neatly above but it works.

jwyman, how much did yours cost in total now?   Mine has been free (well sort of) so far. :-)

The halogen was 8-10 dollars, thremostat/relay unit was $19 after shipping...  Cost of breadboard - $0. Other stuff (i.e. wire, 12volt supply, junction box  already in place).


Here are the formulas for anyone who is interested. It's actually pretty straighforward and can be determined without using areas and without Pi.

* Let d denote the inside diameter of the manufacturer's funnel (measured at the top).

* Let Coarse denote the resolution of the manufacturer's rain gauge (0.04 inches for the OS, for example).

* Let Fine denote the finer resolution you'd like from your modified collector (like 0.01 inches).

* Then you need a funnel whose inside diameter D (measured at the top) is

       D  =  d * sqrt(Coarse / Fine)

* Then set a gain in your station so that it knows each tip of the bucket now represents Fine inches of rain:

      Gain  =   Fine / Coarse.        This is the same as ( d / D )2.

Example:  Suppose your rain gauge has a resolution of 0.04 inches. Suppose the manufacturer's funnel measures 3.875 inches across the top (diameter). Suppose you want to modify the funnel to have a finer resolution of 0.01 inches. So

      d  =  3.875,    Coarse  =  0.04,    Fine  =  0.01,

and you need a new funnel whose inside diameter (across the top) is

      D  =  d * sqrt(Coarse / Fine)   =   3.875 * sqrt(0.04/0.01)  =  7.75 inches,

and you need to set a gain of

     Gain  =   Fine/Coarse  =  (0.01/0.04)  =  0.25

on your station.



freakin' math majors  :lol: :lol: :lol: :lol: :lol: :lol:

Thanks WB, nice!



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