<html dir="ltr"><head></head><body style="text-align:left; direction:ltr;"><div>I was wondering if anyone has tried to connect the GPIO pins of a Rpi to the IR receiver input on a IR repeater? The pinout for the receiver port has +12V, signal and GND. The GPIO ports on the Rpi are +3.3V.</div><div><br></div><div>I figure this should involve connecting an NPN transistor in the circuit so that the GPIO pin can switch the transistor to send +12V to the signal pin but I cannot find an example of such a circuit with two separate GND (IR repeater and Rpi). Can I just tie the GND pins together and have the GPIO, +12V and GND tie to the transistor pins (B, C, E respectively with signal also tied to C)? Would I need more than just the transistor and a resistor or two (1KΩ on the GPIO and maybe 100<b></b>Ω on +12v)?</div><div><br></div><div>My goal is to have the Rpi emulate an Alexa device (using fauxmo) and send fake IR signals (using LIRC?) to the repeater to control my devices (STB, BD, etc.) through voice control. Best idea I could come up with for STBs that don't support Alexa.</div><div><br></div><div>TIA!</div></body></html>