Alt-BEAM Archive
Message #02555
To: beam@corp.sgi.com
From: Steven Bolt sbolt@xs4all.nl
Date: Thu, 22 Apr 1999 16:51:50 +0200 (CEST)
Subject: [alt-beam] Green Thumb gets Finger; plant grows out of control
You may remember the Green Thumb, a device to monitor a plant's
water needs. That project is now entirely topical: It has an
actuator, is solar powered and uses a recycled component - its
`finger'. I combined a model aircraft fuel pump with the motor from a
broken toothbrush. Pumps pretty well on two NiMH penlites, charged
by a 37x82mm solar panel. About 20mA per hour is going in when the
light is good; the pump draws 1.6A, so two hours of charge may
compensate a minute of pumping, and even a thirsty plant needs no
more than 2 pumping minutes a day. Except on hot days - but then
the NiMHs also get more charge. Pictures, schematic and details on:
http://www.xs4all.nl/~sbolt/e-groeneVinger_Duim.html
The guinea pig lemon geranium is now 110cm high and more than 70cm
wide, growing twice as fast as its pre-Thumb predecessors!
Apparently it likes the "just in time" water policy made possible
by the Thumb. Since yesterday it is a kind of cyborg, drinking
autonomously...
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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