[mythtv-users] I know this isn't a hardware forum, but...

[Harry Orenstein]

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.

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 (1K?? on the GPIO and maybe
100?? on +12v)?

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.

TIA!
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