Defeating garage door opener safety signals

RatLabGuy

You look like a monkey and smell like one too
Joined
May 18, 2005
Location
Churchville, MD
Lets say that, er, hypothetically, you needed to bypass the optical sensor system on an electric garage door opener.. lets just say for diagnostic purposes (e.g., a sensor is broken but you'd like to know if the rest of teh system is still usable).
FYI, Sears Liftmaster from 2003ish.
In ths isystem, the "pos" wires from both sensors are tied together, as are neg. Removing altogether leads to a diagnostic code of "connection broken". Placin ga jumper wire between pos and neg gives different code, "sensor shorted", still won't work.

To me thsi suggests it is looking for a specific load on the line? E.g., need soem resistance? Is that right?
Or more directly... how can you bypass this??
 
I couldn't figure it out when I tried to do this, but I was a mere child back then. What I ended up doing was placing the sensors on the roof truss right beside the opener, facing each other. That was a looooong time ago. I wonder if they're still like that.:lol:
 
So, the problem is... one of the sensors is broken. So, that's not really aan option...
 
So, the problem is... one of the sensors is broken. So, that's not really aan option...
As sad as it sounds,
you can buy new sensors from sears/lowes/home depot/where ever for like 20$.
I did that for a buddy's, cause I got tired of dorking with it.
Since they fixed it, problem solved. If it wouldn't of, I was "very careful" with the packaging and planned on returning them.

Oh yea, as for "how to bypass it" you can't easily.
Need something to generate the signal, on those two wires.
http://www.patentstorm.us/patents/6906307/description.html

(To give you an idea)
Hence why I just bought new sensors, and planned on returning em.
 
they vary by models, but The Sears ones if I remember correctly do in fact wok on resistance. You should be able to take a reading on the good one and visiting radio shack. Also a mirror may be useful in this operation....
 
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