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Clifford Heath Clifford Heath is offline
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Default Slow-to-wake garage door opener

On 19/11/15 15:44, isw wrote:
Since I don't use the garage for a car, I don't need to open it very
often. But when I do, I have to push the button on the remote anywhere
up to a dozen times before the door opens. Once it's open, it will close
and open first time every time. Until I close the door and leave it
alone for a few days. Then it's back to the same old tricks.


I've checked the battery, resoldered everything that looked even
slightly suspect (along with some that looked fine, just because) and
replaced the PCB-located switch. I also did a reset on the codes and
started over (it's a "learning" device, not the kind with a bunch of
little switches).

Sadly, I do not have any RF test gear to see if the remote is actually
transmitting.

Other than via the overhead door, access to the garage is through a
rental unit, so being inside when I try the thing "fresh" is not an
option.


Most systems use a rolling code that moves through a predetermined
pseudo-random sequence, where the sequence is determined by the secret
key. The receiver remembers recent codes used, and can detect whether
the code just received is correct in any sequence for the known remotes.
After it has received the neighbour's remotes or other in-band signals
with incorrect codes, it takes more repetitions of correct code
sequences before it's willing to unlock.

https://en.wikipedia.org/wiki/Rolling_code

Clifford Heath.