Re: Drop-out relay

[Robert L Bass <sales@xxxxxxxxxxxxxxxxxxxxx>]

On 16 Apr 2006 16:24:13 -0700, "neo" <tolga.uzuner@xxxxxxxxx> wrote:

> Hi Folks,
>
> I am intending to use an ACP00747 from Linear. It has been pointed out
> to me that the risk with the device is that if someone rips it off the
> wall, they need only short the wires to trigger the doors.
>
> Apparently, the fix to this is a drop-out relay... can someone
> recommend one for me, suitable for this purposes ?

Any DPDT relay will do the trick.  You run the door trigger circuit through the
C and N.O. terminals of one pole of the relay and then through the output
terminals of the Linear device.  Run power to the relay coil through a N.O.
tamper switch on the protected device and then through the other C and N.O.
terminals of the relay.  As long as the device is unmolested the relay will
remain energized and the circuit from the door operator will be able to be
completed by activating the Linear unit.  If the device is tampered the relay
will drop out, breaking the circuit and thereby disabling the outdoor control of
the garage door.

As to sources, you can order a DPDT relay online at any of a hundred retailers,
including my online store.  You can also buy one at any Radio Shack store
probably for about the same price.  If this isn't clear, contact me and I'll
draw a simple diagram for you.  This one is easier to do than it is to explain.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

--

Never underestimate the power of very stupid people in large groups.