Controlling Marantz amplifier using Arduino via “Remote” socket | Hacker News Reader

Controlling Marantz amplifier using Arduino via “Remote” socket

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I did this with a Philips CD player and a Commodore-64 back in the day, using the system as a "modern" alarm clock which would wake both me as well as the rest of the house - and probably some neighbours - by blasting out, say, 'Highway to Hell' at the correct moment. This all came about from my curiosity about that "remote control" socket on the back of the thing. I did not know about RC-5 or anything but decided on a whim to send a letter (as in "paper in an envelope", this was before email was a thing for companies like Philips) to Philips inquiring about the correct way to interact with that socket. Lo an behold, they replied by sending me a stack of paper detailing the RC-5 protocol complete with required voltages etc.

With that information in hand I made an adapter for the user port on the CBM-64 and a program which bit-banged RC-5 through it. It was quite satisfying to see the thing react to some command typed on a "remote" keyboard, just imagine the possibilities...

Well, one of the possibilities it lacked was volume control... which sometimes made the wake-up call quite alarming...

That CD player was the first, and also the last one I ever owned. I still have it in a box somewhere but never use it. CDs were too expensive for too long a time which made them an easy prey once it became possible to download music.

That reminds me of my old CD setup: I had 3 of the Sony 200-disc CD changers and a "Slink-e" device to computer control them. I wrote some Python code that would pause shuffle all the tracks on all the discs, and hold two of the devices paused while the third was playing. When it reached the end of the track, it would pause that one, unpause another one, and then seek the newly-paused player to a new song and pause it there.

It was really empowering to have this because: I had more CDs than a single player could handle, and it took a quite a long time to change discs, maybe 10-30 seconds.

Of course, this was back in the early '90s. By the mid to late '90s I had ripped all my CDs to mp3s and later spent 2 weeks re-ripping them as FLACs.

http://www.whanafi.net/Sliinke.html

Old skool hacking was so rewarding as a kid as you learned about both hardware and software. Now, I feel like the younger curious minded individuals are primarily software centric. At least with things like Arduino/Pi/etc, you can get back into hardware as well.

Single board computers like the Raspberry Pi and microcontrollers like Arduino above all have made this type of hacking far more affordable. While it was possible to use the parallel printer port as a makeshift user port replacement it came with the baggage of an entire desktop or notebook machine taking up space, using power and making noise.

Check out the ESPhome project[1], now part of the Home Assistant universe. It makes creating ESP32 projects a breeze and has native IR transmit capabilities. This will let you tie the device into Home Assistant which bring integration with nearly everything. You get a great mobile interface, automation engine, and hooks to nearly every smart device currently being sold.

[1] https://esphome.io/components/remote_transmitter.html

Interesting!

I've been looking for ways to integrate my Fujitsu mini-split A/C heads, and while Fujitsu offers a Wireless LAN device [1], it appears to be a 3rd-party device that just emits IR to control the head. The device also depends on proprietary Cloud control and app, and while these have been reversed for HA integration, it seems like ESPHome can serve as an alternative.

[1] https://www.fujitsugeneral.com/us/residential/benefits/wirel...

I have done exactly this with my own ducted Fujitsu system. I initially used the IRMQTTServer project from the IRremoteESP8266 library, which integrates into HA through MQTT.

https://github.com/crankyoldgit/IRremoteESP8266/blob/master/...

I now use esphome on absolutely everything and it's WAY better, and I was able to eliminate MQTT from my stack. I could have used the built in climate component—it worked 99% perfectly. But in order to make the Fujitsu climate component behave consistently with the air conditioner itself (e.g. setting "dry" mode forces "auto" fan speed) I re-implemented the climate component as a custom component.

https://gist.github.com/sjwright/8591ebd36b53bbed588179135c2...

I have three zones, so I took three "D1 Mini" style ESP8266 clones, attached an IR emitter to D5/GPIO14 and embedded it inside the air conditioner itself. Each AC has a little daughter board for status LEDs and the IR receiver; there's also 12 volts going to that which I use to power the D1 Mini, which in turn regulates a 3.3V output for powering my IR emitter.

Awesome! Thanks for the info :)

Love it - I dream of an alternate universe in which IoT was done with infrared, RCA jacks, and 8 bit microcontrollers instead of JSON, Docker and billion-transistor SoCs.

I have a raspberry pi set up with an infrared LED to control my old NAD amplifier. It's from the time period where no stereo amplifier was complete without a motorized volume knob, so the knob physically turns when I control it from my phone over HTTP - to me this is much cooler than a touch screen or voice control :)

Rotel still allows this, at least on models a few years old. I have a RA-1572 amplifier, and it's a joy to work with. Plug a serial or a network cable, and start talking to it. It supports the same commands over RS232 or TCP (basic TCP, not HTTP or what have you – just don't open too many connections too often, or it will choke). They also support IR IN / OUT, but I've never attempted to work with those. I seem to remember that the IR codes were documented somewhere, but I can't remember where I've seen that (I've never needed them).

The protocol is documented here: https://www.rotel.com/manuals-resources/rs232-protocols. The TCP commands are the same as the RS232 commands, the docs say on which port it listens, etc.

I've started building a "remote control" to an amp to be used from an I3 bar: https://github.com/vladvasiliu/amp-mate-rs (older Python version which doesn't do much: https://github.com/vladvasiliu/amp_mate).

I created a Home Assistant plugin for the RS232 protocol:

https://github.com/claes/homeassistant-rotelserial

> I have a raspberry pi set up with an infrared LED to control my old NAD amplifier.

Interesting - could you share a little about how you have done this?

I have a Raspberry Pi that I use as a jukebox, connected to a NAD C320BEE amplifier, and I would like the jukebox to turn the amplifier and (active) loudspeakers on, using a usb-controlled relay, when I unpause mpd and off when I pause it, but unfortunately when the amplifier is powered on, it is humming until a source is physically selected!

Yeah absolutely - the last two images on this page show the hardware:

https://peteshadbolt.co.uk/writing/rpi/

It works great, just bouncing IR off the walls in my room to put the amp on standby, change volume, switch input, mute etc etc.

The software side is done with LIRC. LIRC is very old and a bit awkward to get running but it works.

Send me an email at hello @ peteshadbolt.co.uk and I can share the LIRC configuration as well as an Ansible role to install LIRC etc.

An 1/8 inch mono jack for remote control is somewhat common, but there's no broadly accepted standards for the protocol. So what's described here (RC-5) probably only works for Marantz and a few other brands. Other brands may have their own way of doing it. Here's a blog post on Pioneer's way of doing it, which they call "SR": https://blog.eikeland.se/2012/09/09/pioneer-sr-link-control/

Sony equipment use to have a way of doing this as well, via the S-Link[1] / Control-A1 bus on stereo equipment (and some video equipment too, I believe). There's a handy Arduino library[2] for doing this - a couple of years ago I added support for the dual cassette deck I have, although the PR hasn't been merged yet. I'd also be remiss if I didn't mention the Slink-e [3], a commercial product that seemed to be very capable (unfortunately it is now discontinued).

In fact, these protocols are (I believe) more capable than a regular "Remote" socket since they allow bi-directional communication, meaning you can both send commands to the equipment and request data from them. But it's been a while since I've looked at them in detail.

Also, I recall being confused by the several (seemingly incompatible) systems offered by Sony: S-Link, Control-A1 and Control-A1 II.

[1] http://www.brian-patti.com/s-link/

[2] https://github.com/Ircama/Sony_SLink

[3] http://www.nirvis.com/slink-e.htm

The HEOS line of Denon/Marantz also has a HTTP API with a fully public API specification[1], which is great!

You can use the ESP wifi connection to control it if you want to and it has quite a few features (afaik you can do everything the HEOS app can do). Do other vendors also have such an open approach?

[1] https://www.marantz.com/-/media/files/documentmaster/marantz...

This seems like the right thread to ask: Has anyone seen a HDMI-CEC embeddable amplifier board?

I'd love to DIY some speakers or a soundbar, maybe something like the Tech Ingredients "Worlds Best Speakers". But the convenience snob in me doesn't want to go back to a Harmony, or other multi-system remote. I've gotten really spoiled by being able to use my TV remote to control the soundbar volume, TV, chromecast, etc... all over HDMI.

I've done some searches for an amplifier board, like the youtubers are using to make homemade soundbars. Either I don't know the right combination of search terms, or they just don't seem to make such a thing. I don't REALLY want to make a bunch of space for a receiver, I'm fairly space constrained in the TV area because reasons.

https://youtu.be/CKIye4RZ-5k

Maybe I'm way off base from what you're asking, but would a Raspberry Pi with an amplifier hat solve this?

I _think_ Rpi supports HDMI-CEC, but then again I've never seen CEC working properly outside of the fantasy realm

One of the options I had seen was some sort of a CEC communication board. Looked like it might be for sending like a "turn on" signal to other devices.

I've had pretty good luck with CEC with my 5 year old Samsung TV. Compared to my in-laws new house that has a Denon receiver and IR blasters and some universal remote, that they paid big bucks to have an AV company install, CEC is like a space age rocket ship!

It may surprise the average consumer, but one of the features found in higher-end AV equipment is not just more channels or watts, but control idempotentcy.

When doing home integrations in a past life, we would often choose high-end Denon/Marantz over similarly spec'd Onkyo/Pioneer units specifically for this reason.

Serial ports provided the ability to more robustly connect and get device feedback, which was huge. Also, discrete on/off and source selection were all but required for a fluid integration.

Imagine trying to keep a home integration system synced with the state of an AV receiver if all you have was an IR transmitter and some Source Up/Down commands. We attempted a couple of these and every time the client was so (understandably) disappointed that we started requiring pricier equipment models in order to make the system meet expectations.

I have a number of 1980s-vintage Technics AM/FM radios around the house. All of these use an RCA-style plug labeled "REMOTE", and I believe are intended to be used for hooking a Technics radio up to a Technics stereo amplifier. Sadly, the manuals for the tuners I do have are mostly mum on what it does - they're like bad API documentation saying `remote: the remote input` or such.

I have a passing interest in doing something with this on all of the tuners, but all I've really managed to reliably do is get them to tune to exactly 1000kHz AM if I short the center to ground.

Check whether you can control your model using lirc, using an audio cable and a soundcard's line-out. Had it running with an Onkyo receiver.

Is it in-only, like IR remotes, or can you get info out?

There is an “output” to these RC5 devices, but it’s not for what you might think.

It’s for relaying remote signals to other equipment. So you have one remote to the unit and to the output of that you hook another device or an IR extender or whatever. This can allow you to have one piece of equipment “front and center” and other equipment in a closet.

Plagued by the same vendor compatibility issue as everything else. I don’t know why I ever had even remotely high hopes for HDMI CEC to work as intended (it has gotten better in the past couple years).

So you can get “data out” but not values and addresses. Just another device’s input / requests.

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