You could also use a resistor thermally bonded to a thermistor or a Dallas 1wire sensor. You apply voltage to the resistor to make it a little heater and when the temp rises significantly on the sensor you know it is out of water. You don't need much heat, just enough above ambient to notice a difference.
-Jerry > On Dec 4, 2014, at 12:29 PM, Jason Barnett <[email protected]> wrote: > > Here is my solution to the whole watering problem. It hasn't failed me yet. > http://www.sharperimage.com/si/view/product/Pop-Up-Xmas-Tree/201754 > > > >> On Thu Dec 04 2014 at 11:52:35 AM Nathan McCorkle <[email protected]> wrote: >> On Thu, Dec 4, 2014 at 11:15 AM, Denis Heidtmann >> <[email protected]> wrote: >> > The scheme I proposed requires a sealed >> > (air-tight) container located above the tree stand. The hose delivers >> > water when the water level in the tree stand drops below the end of the >> > hose, allowing air to enter the hose, releasing water. When the hose end >> > is >> > in the water in the tree stand no air gets in, and no water flows. >> > >> > Maybe his system is easier to make aesthetic. >> >> Hmm, you could probably do something crazy with frosted 'natural >> colored' tubing, LEDs, and lots of water-filled tree ornaments. Rig up >> the LED to somewhere on the tubing (opposite the end of the tubing >> where it connects at the base of the tree) and hope the frosted edge >> of the tubing diffracts and causes the length of the tube to >> illuminate. Or something like that. >> >> Maybe you would need lasers instead of LEDs to get more length of the >> tube to illuminate. >> http://vimeo.com/65933495 >> >> Fun ideas! >> _______________________________________________ >> dorkbotpdx-blabber mailing list >> [email protected] >> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber > _______________________________________________ > dorkbotpdx-blabber mailing list > [email protected] > http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
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