Many older amplifiers support wired remote control through connector jacks or ports. My 10-year old Marantz also supports this function, using a simple RCA connector.

Originally these were used with external IR receivers when the unit was not kept in plain sight.

I wonder if there is a way to control the amplifier using an Arduino, which probably means by generating the required signal over the connector instead of receiving it from an IR receiver. Any pointer to a similar project is appreciated as well.

  • Sounds like the sort of thing which might be possible. Unless someone happens to know specifics of how they work, a spec for the connection, and/or a circuit diagram of either/both the amp or/and a suitable controller would help a lot. – Mark Smith Mar 17 '17 at 14:41
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    it's probably just the same pulses as the IR, but you'd need an oscilloscope or a service manual to be sure. you can always improvise – dandavis Mar 17 '17 at 16:53
  • You'd have to know the protocol, which is probably proprietary. I'd just use IR, by connecting an IR led to the Arduino. – Gerben Mar 17 '17 at 16:58
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    That's what I was assuming - that you would stand a good chance of guessing the protocol with some trial-and-error, but it would be really helpful to have some idea of how it works electrically to get you started, otherwise you've got two degrees of freedom (and you might possibly damage the device). Two connections (as on an RCA) isn't enough for an IR receiver (you need three) so it's not immediately obvious (to me, anyway) how it would work. Even a working example IR receiver circuit would get you started. – Mark Smith Mar 17 '17 at 18:05
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    i seem to recall an article 20 years ago that said marantz gear could interact with sony using those control signals. if that's true, or maybe just for an overview look into sony's... – dandavis Mar 18 '17 at 0:16

According to this thread on remotecentral the signal on the RCA connector is just the inverted signal that the IR-LED receives. So if you load an RC5 library and invert the output (0=1 and 1=0), you should be able to send codes to that connector with an arduino. Or even better, use an ESP8266 and control it over wifi ;)
The RC5 codes and their functions are in this nice excel sheet or use this information if you want to send raw hex

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