RE: Whoosh, thud - motorised sliding doors

["Rodney Hall" <rmh@xxxxxxxxxx>]

Martin Howell <> wrote on 15 January 2006 20:17:

I am planning to build a couple of large sliding doors to close off
parts of my currently open plan ground floor (don't ask).  They will
be full ceiling height and around a metre wide, with full height
glass panels, so they'll weigh a fair bit - obviously, I need to
motorise them :-)

Motors and gears etc are not a problem - windscreen wiper motors fed
from a small 12v lead acid battery, kept charged by either the mains
or a small solar panel, letting me still open the doors when there's
a power cut, plus some means of disconnecting the drive to open the
doors by hand if the motor gubbins should go titsup. Did this before
with a huge double garage door in my last house as an experiment and
its still
in daily use 15 years later.   The problem is control of the
open/close
sequence and the need to have safety features included, squashing a
small child would probably not go down well.

So I need a circuit to control the open/close mechanism.  Ideally,
pressing the button (or breaking an infra red beam) makes it open,
then wait a predetermined time (or wait for second beam/sensor to be
tripped) before automatically closing it.  There needs to be a safety
mechanism which detects if someone is being squashed and
automatically reverses the door, or stops it.  It would be neat to
have it in touch with other things - burglar alarm to auto lock the
doors when the alarm is set; smoke detectors to automatically open
the doors if the alarm goes off; and anything else I can think of.
Opneing speed is interesting as well, don't want to press the button
and then wait for 30 seconds while it opens, but if it opens too fast
it may be difficult to keep it on its rails - my guess is that it
needs to take no more than around 3 seconds to fully open

Has anyone come across anything like this in their travels?  Or is
clever enough to knock up a quick circuit diagram?  I can build the
electronics, just can't design 'em.  I could make it simple, with
buttons for open and close, and a couple of microswitches to limit
the travel, but where's the fun in that?  Any suggestions and/or
ideas will be most welcome, many thanks

Martin


Martin,

I have a circuit that I have had in use since 1981 controlling 4 sets of
curtains that could be used for what you want. Open/close points are
detected by the increased motor torque tripping an op-amp, so it will also
stop on meeting an obstruction and it runs a 12 volt motor, so would suit
with a little adaptation. I can email the circuit off-list if you like.

--
Rodney HALL
Heywood, Lancashire
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rmh@xxxxxxx
http://rmhh.co.uk/
http://rmhh.org.uk/
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