GarageMote Relay won't trigger garage opener [solved]

[Tony Weil]

I just purchased, assembled and installed a new GarageMote R2 on a Chamberlain AccessMaster 1/2 hp garage door opener. Open and Close sensors work great as does the integration with the Pi Gateway.

When I activate the relay from the "Open" or "Close" button in the Pi Gateway, I can hear the relay click, but the garage door does not activate and open. I tried the following tests to narrow down the problem:

1. Put a screwdriver across the "switch" terminals on the garage door opener. Door is activated and opens, so I know I have the correct two terminals. Door Opened, PASSED

2. With the garage door opener unplugged, attached a continuity tester to the "switch" terminals on the garage door opener and activated the "Open" button from the Pi Gateway. Continuity FAILED

3. With the garage door opener still unplugged, disconnected one of the relay wires from the opener, attached a continuity tester to the loose relay wire and the "switch" terminal with the second relay wire attached. Activated the "Open" button from the Pi Gateway. Continuity FAILED.

4. With the garage door opener still unplugged, disconnected both of the relay wires from the opener, attached a continuity tester to both relay wires. Activated the "Open" button from the Pi Gateway. Continuity PASSED.

5. Plugged the garage door opener back into power and reconnected both relay wires. Increased relay pulse time to 500ms and reattached relay wires to garage door opener. Door does not open. FAIL.

6. Plugged the garage door opener back into power and reconnected both relay wires. Put continuity tester across relay terminals on GarageMote. Activated the "Open" button from the Pi Gateway. To my surprise, door opened and almost knocked me off the ladder! I think the continuity tester beeped also.

Stumped... Any ideas...

Thanks,
Tony

[sparky]

Tony,

Sounds like the wires from the GarageMote to the door opener were not making good contact.  Found that I had to twist the wires together before inserting them into the opener.

[Felix]

Tony,
Test the relay output contacts with your DMM continuity, if that beeps, the GarageMote is OK and maybe as sparky suggested - contacts are not strong enough at the opener side or something...
Another thing that's possible is the delay that the RELAY is ON. If nothing works, increase that by 100ms or so, not more than 1s should be necessary to trigger an opener.

[sparky]

He already tested output with his meter, tested good.  When he put the wires back together the opener worked

[Felix]

Ok I skim read the post and missed the essentials
BUT that proves the GarageMote is OK and relay works.
Depending on DMM the relay pulse might be too short to hear a BEEP.
In #6 you say it works - although this is with the DMM probes on the relay terminals. Is that the ONLY way it works?
The relay is just a wire that will short, equivalent to the screwdriver. You mention you tried 500ms, I doubt it needs more than that, usually a short 200ms pulse is enough.

[sparky]

I'm still betting it's the wire terminals on the opener, had the same problem.   Wires need to be twisted to make good contact with them speaker type terminals

[Felix]

I suggest first doing another test on the GM terminals with nothing attached.
Measure the DMMs ohm value with probes shorted. Should be under 1ohm (even with crappy leads).
Then activate the GM relay for 1second or enough to get a beep and ohms reading on the DMM. Ensure good contact with the terminals. I would expect the ohm value to be very close to the shorted leads value. IOW the relay to not introduce any significant internal resistance to the "short".

If all of that is good, then the only remaining 2 things are good contacts and long enough delay to satisfy the opener.

[Tony Weil]

Thanks for all the suggestions. I'm headed out of town. I will pick this up later next week try some of your ideas.

[Tony Weil]

OK, I got it working today. The final solution was to replace the pair of wires (Cat5 cable that came with the kit) from the GarageMote relay terminals to the Opener terminals with some 22 AWG solid wire. 

Now onto figuring out how to program the Pi Gateway to check the garage door at midnight and close it if it is open.

===================

For those interested in a continuing mystery, I tried the following tests with the existing Cat 5 wires. I don't understand what was going on. All tests were made with garage opener unplugged.

1. With a meter across the GarageMote terminals and no wires, when I activated the relay, the meter read under an Ohm. Good.

2. Attached Cat5 wires from kit to GarageMote, but not Opener. With a meter across the unconnected ends of the wires, when I activated the Garage Mote relay, the meter read under an Ohm. Good.

3. Carefully attached Cat5 wires to Opener, twisting with other wires. Measured O Ohms between each GarageMote relay terminal and each Opener terminal. Good.

4. Here is the mystery: When I activated the GarageMote relay with the Cat5 wires connected from the GarageMote to the Opener, I could hear the relay click, but the meter read No Continuity! I tried it several times. Go figure.

[sparky]

Tony,
Glad to hear you got your GarageMote running.

Regarding your next project, have you read the thread posted below?  It might give you some ideas for automatically closing the garage door.

https://lowpowerlab.com/forum/pi-gateway/scheduled-events/msg14758/#msg14758

[Felix]

4. Here is the mystery: When I activated the GarageMote relay with the Cat5 wires connected from the GarageMote to the Opener, I could hear the relay click, but the meter read No Continuity! I tried it several times. Go figure.

Very weird, but 22GA wires solved it.. so the difference is in wiring somehow?
The kit wire are just twisted pair cat5, should make no difference, and you're the first to report a wiring problem like this.
Glad it's solved though.