https://wejn.org/2021/04/multi-weekend-project-reversing-yamaha-yas-207-remote-control/

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Written on 2021-04-11

Multi-weekend project intro: Putting the fear of AirPlay into Yamaha
YAS-207 soundbar

bluetooth raspi reversing unix yas_207


Introduction

Recently I bought a "Yamaha YAS-207" soundbar to replace our old and
clunky 2.1 PC-speaker based sound solution for TV and AirPlay.

yas 207 soundbar

I'm happy with the sound itself. However --

From the beginning I was hoping to use the Yamaha soundbar both for
our TV (that we use for Switch and movies) but also for the AirPlay
speaker solution I cobbled together a while ago^1.

And before someone asks why didn't I buy the more expensive YAS-209
(or the even more expensive YSP-2700) that sports the AirPlay
natively: well, I like my devices fairly dumb. No Alexa/Google Home/...
for me, thank you.

Also, where's the fun in spending 150 CHF more when you can buy the
cheaper version, and then spend multiples of the price difference
(and a lot of time) to get a similar feature set?

Anyway.

The purpose of this project is to get AirPlay and TV to work
seamlessly with YAS-207. And for that, I need to completely reverse
engineer the YAS-207 remote control interfaces first - in order to be
able to control the soundbar programmatically.

Hardware overview

The Yamaha YAS-207 has four inputs: HDMI, TOSLINK, Analog (Jack
3.5mm), and Bluetooth.

It sports infrared remote control, and a Bluetooth interface.

The Bluetooth remote control doesn't have a published protocol, so
normally one would be left at the mercy of an Android/iOS app. They
call the app "Home Theater controller".

Plan

The plan is simple: First, reverse engineer the infrared remote
because it might be beneficial to have a single remote for both the
TV and the soundbar. This part should be a piece of cake.

Next up, reverse the Bluetooth communication protocol.

Finally, make a Raspberry Pi based AirPlay speaker that uses the
remote control to automatically adjust the device's parameters (on/
off, input selection, volume, surround settings, etc)

This will follow in a sequence of posts, all tagged with yas 207^2.

Execution:

  * Part I: Reversing the Yamaha YAS-207 infrared remote protocol
  * Part II: Yamaha YAS-207's Bluetooth protocol: basic recon
  * Part III: Streaming Bluetooth Capture Data to Wireshark without
    Btsnoop Net Support Enabled
  * Part IV: Yamaha YAS-207's Bluetooth protocol: first real progress
  * Part V: Yamaha YAS-207's Bluetooth protocol reversed
  * Part VI: Yamaha YAS-207's Minimal Client (and a Soundbar Fake)
  * Part VII: Yamaha YAS-207 vs. Shairport Sync over TOSLINK

All done (for) now.

 1. From PC speakers, a raspberry pi, a usb sound card, and a sonoff
    switch. Because just like one does not simply walk into Mordor,
    one also doesn't want the speaker powered on all the time. -

 2. And should put the Comparison of USB Bluetooth adapters in Linux
    in its proper context. :-) But I'm getting way ahead of myself. -

- - |
(c) 2021 Michal Jirku. I speak only for myself.