watering system, second attempt.

From: andy (news4_at_earthsong.free-online.co.uk)
Date: 08/04/04 

Date: Wed, 04 Aug 2004 21:33:12 +0100

after the comments on my first version, i've redesigned the circuit using
CMOS ICs and a mosfet to switch the coil. I was meaning to get it working
before i posted the new design, but i'm waiting for some parts, so i'm
posting it now to see what people think. as before, i would appreciate any
comments on how i've done it.

mostly what i want to know is if there's
anything that will stop it working the way i'm expecting, cause parts to
fail, cause a hazard, or if i've missed any obvious simplifications to the
design i've come up with. it's a bit more complex than before, because
i've added a feature to water in the morning, evening or both.

I've tested the part of the circuit that gets the light on/off signal from
the LDR using the 393, and xors it with the 'force watering' switch
signal, but then a chip failed and i'm waiting to get another one.

http://www.niftybits.ukfsn.org/electronics/daily-water-with-chip.jpg
http://www.niftybits.ukfsn.org/electronics/daily-water-with-chip.png

if you still think it's junk then say so, but i'd like to know why. 

-- 
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remove 'n-u-l-l' to email me. html mail or attachments will go in the spam
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