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I'm trying to control my garage door remote with a GPIO pin from my Raspberry Pi. The following is my schematic diagram of what I am thinking of using:

enter image description here

Would there be a potential problem if I were to hold down the push button and activate the transistor and allow current to flow through at the same time?

*If there is no conflict could you explain why that would be the case?

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  • \$\begingroup\$ How many buttons do you have? \$\endgroup\$ – Ale..chenski Jan 18 '18 at 1:19
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There will be no conflict between the transistor and the button, but the whole circuit won't work in first place. To get it work as pictured, the GPIO signal must have 9-something volt level, which you don't have.

But you can do try this instead: enter image description here

ADDITION: There will be no conflict because there is nothing to conflict with - both components (a transistor and a switch) are both switches connected in parallel, so it is one OR another. Zero voltage across emitter-collector doesn't hurt, and even in the original (incorrect) schematics the base-emitter junction will be reverse powered, and won't conduct anything into RPi (as long as reverse e-b voltage doesn't break the transistor).

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    \$\begingroup\$ Assuming the remote control used active low buttons. Which op diagram indicates it does not. \$\endgroup\$ – Passerby Jan 17 '18 at 23:12
  • \$\begingroup\$ @Passerby, most GARAGE remote controls just use power switch to operate, there is no "active low" or "active high". So shows the OP diagram, and thus my proposal comes. Actually, the battery is likely 12V (typically "23A" style), not 9V. \$\endgroup\$ – Ale..chenski Jan 18 '18 at 1:12
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If you don't know the circuit around that switch, the safe thing to do is to use a small reed relay - the relay provides full isolation between the Pi and the remote, and its contacts won't care about polarity or AC/DC.

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