Re: How to use Liftmaster garage door IR safety sensors for other uses?

[Art Todesco <actodesco@xxxxxxxxx>]

On 6/25/2012 5:37 PM, Bob F wrote:
> I picked up a couple pairs of these Liftmaster 41A5034 garage door safety
> sensors, which I thought I might be able to use for other sensing on my homebrew
> home control system. Does anyone know what voltage/current the sender needs, and
> what connections the 2 wire detector needs and how it signals. They both have
> white 2 conductor wire with a black line on one of the conductors.
>
>
I have them on my 2 garage doors.  I installed an addition unit called
Garage Door Butler, which automatically closes the door if accidentally
left open.  What I'd like to do, is to use the info from the safety
sensors to reset the Butler unit so that each time you break  the beam,
the Butler would reset back to the 10 minutes I have it programmed for.
  But, I too, don't know how they work.  I would like to have a small
relay operate whenever the beam is broken.  The contact on the relay
could easily reset the Butler.  The one odd thing I've noticed is that
both the light source (IR) and receiver box have 2 wires each.  They
connect in parallel and then go to the opener unit as just 2 wires.
I've want to put a voltmeter/oscilloscope across the wires and see what
it looks like, but just haven't had the time.  I've also wanted to call
the guy that installed the doors (new house 3 years old) and see if he
has a schematic, but I haven't done that yet.  I'll keep an eye here and
also will let you know if I find out something.