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From: Terry Pinnell
Subject: Re: I can't find the solution for such "simple" problem. Motorized drapes
Date: Sun, 05 Jan 2003 12:46:50 +0000
NNTP-Posting-Date: Sun, 5 Jan 2003 12:47:17 +0000 (UTC)
X-Newsreader: Forte Agent 1.92/32.572
>I have motorized the drapes on my living room and was going to install
>one microswitch at each end of the travel.
>The switch would operate a dpdt relay that invert the motor sense and
>at the same time would switch power off.
>A push ON switch would reestablish the power and the cycle would be
>repeated at the other end. Simple isn't ?
>I can't design a circuit that can do the desired action without using
>at list one more relay , a special type of relay ( ratchet ) or other
>mechanical operating system.
>Can you ?
Yes, I built a similar bedside-operated window-opener many years back.
Allowed me to keep the window closed while reading in bed without
light-attracted moths and other bugs getting in, and without having to
then get up to open window for fresh air overnight.
A pair of N/C microswitches (SW1 and SW2) are carefully placed at the
two extreme positions so that they are respectively opened when the
drapes reach the appropriate fully open or closed positions. A
standard DPDT switch controls whether you want to open or close, and
also gives you visual indication of the state (e.g. if you're too
short-sighted to see the drapes, or too hung-over to open your eyes).
A similar query arose here a year or so ago, and you can see the
circuit and explanation at
I think it's very similar to Tony's suggestion.
Hobbyist, West Sussex, UK
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