I want to control this remote in the picture using GPIO. Am Newbie. I followed a cookbook to connecting the relay directly to the garage door motor but thought "Why not use the remote and perhaps control BOTH doors with one PI. My pals made fun of my idea saying I would have to invent a finger that presses the remote. I pulled apart the remote and soldered the wires A, B, C, and D. Now when I touch A and B wires I get a blink from the LED which tells me I am creating the connection same as pressing that button. C and D activate the other button. I also realized that I can cross other wires like A and C and get the button to press as well. Basic stuff. Here is my question:

The cook book says that the relay is sending voltage through to the garage motor via the RED and WHITE cables (E and F in pic). Am I doing something bad by connecting ABCD to relay and trying to get GPIO to close circuits? I suspect I am sending voltage the system does not need.

Wiring Diagram of connecting remote to Rasberry PI

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    disconnect the wires at E and F ...... touch the wire ends together ...... the relay does exactly the same thing – jsotola Mar 6 '19 at 17:35
  • the three buttons may have one common connection ...... if they do have a common connection, then you only need three wires for the two buttons ....... the common would go to one side of both relays – jsotola Mar 6 '19 at 17:39
  • @jsotola - Thank you for your prompt response. I am not sure how to ACCEPT your answer in this system beyond saying "Thanks!" I realized the three wire once I tried all the combos and it makes perfect sense. – Chris Mar 7 '19 at 1:28

To answer your question, "No - you are not doing anything bad." But you must be sure you're connecting these wires to the correct points.

Which brings me to my point, and an important part of the answer you need: The photo you posted with your question is good to provide some context, but it does NOT have the details needed to allow someone to answer your question (verify your assumptions in this case) definitively. Those details are typically provided in a schematic. Fortunately, in this area of SE, we have free access to a schematic tool that allows us to embed a high quality schematic in our questions and answers. You should learn to use it - here's how to get started.

Finally, wrt your statement about "sending voltage": When thinking about electricity, it may help you to form an analogy with plumbing! Think of voltage as being the amount of water pressure, and the current as the amount of water that's flowing. Voltage is often referred to as a "potential", and as such, it is "static". Current is a flow or movement of electrons. And just as in the plumbing analogy, the higher the pressure/voltage the greater the amount of water/current that flows. This analogy won't take you very far, but may help initially when thinking about electricity.

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  • Than you as well and I will check out your recommendation on schematics. – Chris Mar 7 '19 at 1:30

The relay does not "send" any voltage. All it does is connect or disconnect (close or open) the two wires connected to the relay. So it should work fine.

As jsotola said:

disconnect the wires at E and F ...... touch the wire ends together ...... the relay does exactly the same thing

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  • Thank you for the clarification and support on the first answer I got. – Chris Mar 7 '19 at 1:30

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