Whoosh, thud - motorised sliding doors

[Martin Howell <martin.howell@xxxxxxxxxxxx>]

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