Re: Saving the Garage Door Opener?

To: tesla-at-pupman-dot-com
Subject: Re: Saving the Garage Door Opener?
From: Jim Lux <jimlux-at-jpl.nasa.gov> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Thu, 15 Oct 1998 17:30:49 -0600
Approved: terryf-at-verinet-dot-com
Tesla List wrote:
> 
> Original Poster: Gary Lau  13-Oct-1998 2156 <lau-at-hdecad.ENET.dec-dot-com>
> 
> >Original Poster: "Coiler" <mycroft-at-access1-dot-net>
> >
> >I'm trying to find a way to move back into the garage. But there is this
> >pesky little door opener in the way. And my wife has been fairly
> >understanding of my purchasing of all the hardware for the coil, but
> >draws the line at my removing the door opener. Since my door and
> >operating hardware are all metal, I thought I might be able to protect
> >the system in this manner, someone please tell me if I am all wet.
> >
> >1) Attach runners to my RF ground.
> >2) Build a 'faraday cage' of aluminum mesh around door opener unit
> >   itself, with a door for the antenna to hang down for normal operation,
> >   to be lifted up inside the cage during coil runs. Attach this cage to
> >   RF ground.
> >3) Yank the plug during the runs
> >4) Ground the door via clamp.
> >
> >Do I stand a chance?  I already know that running the coil in the next
> >bay over (I have a 3-car) confuses the obstruction sensor to the point
> >where it shuts down, requiring me to unplug the door opener to reset.
> >Thanks
> >Michael Baumann
> >Coiler, Homebrewer, Nerd. mycroft-at-access1-dot-net
> 
> I believe the most important thing is disconnecting all wires which enter
> or exit the opener enclosure.  This means unplugging the power cord and
> coiling it up as closely as possible to the box (assuming it's out of
> strike range) AND disconnecting the control wires to the sensors and
> switch.  I even stuff the little bit of antenna wire hanging out back
> into the box.  Any wires which stick out of the box will capacitively
> couple to your TC, even one bay over.  It's a pain to do and undo all
> this each time I run my toy, but I do enjoy my garage-coiling priv's,
> which would likely expire if I took out the opener!  I also unplug my TV
> cable, computer and all peripherals and disconnect the modem connections.
> 

Why not get a suitable multi pin connector to make the
connecting/disconnecting process easy. The circular plastic connectors
from AMP are <$10 a pair (M and F) and would do nicely. Then, you could
disconnect one connector, coil up the cord(s) and stuff them into your
shielding cage. You can run the antenna wire on the same connector as
well.

Alternately, shield everything. Run the obstruction sensor wires through
thin conduit (or use shielded cable) (I'd use that really thin 3/8" flex
conduit, because it is easier). You will have a problem with the
antenna  of course, but a little ingenuity should get you through. The
RF for the garage opener is about 300 MHz, so a small cap in series
(.001 uF) wouldn't make any difference, but would block the few hundred
kHz from your TC.