Fellow pilots, when it comes to changing the settings on your VTx, the future has arrived! On all but the cheapest models DIP switches have gone the way of the dinosaurs and now there’s a technology that makes single buttons and rows of LEDs seem like steam power.
SmartAudio is Team BlackSheep’s protocol for communication between and OSD and VTx by using the audio channel. Until recently it was only used by TBS themselves in things like the Core Pro but now support has made it into BetaFlight.
What does all this mean to you? Solder up one wire to a spare UART on your FC and you can set your VTx band, channel and power from your Taranis. There are a few steps you need to follow and updates for perform but it's not that tricky - let's get started.
What do you need?
- A F3 or F4 flight controller (Most F4 board don’t have inverted telemetry so you will need to so some faffing to get an inverted output from your Rx) running Betaflight 3.1.x
- A TBS Unify Pro VTx (V2, HV or HV Race)
- A FrSky radio running OpenTX 2.2.0 RC12 or later (there's a bug in RC11 that stops this working)
- Smartport telemetry already up and running
- The BF LUA scripts
Hardware prep:
First up, let’s get things connected. The white wire in the TBS wiring loom is the audio line and this is the only extra wire you need to connect to make this work.
UART1 was spare on my Kombini flight controller so I simply soldered that white wire to the TX pin. In this case it’s just above the UART3 RX pin which is my SBUS connection.
Setting up Betaflight:
The second and final step to prepare you quad is to tell Betaflight what you just did. Load up the Configurator go into the Ports tab and for your chosen UART select “TBS SmartAudio” in the Peripherals drop down box. You can leave the baud rate as AUTO.
Updating your Taranis:
Over on the radio side of things, we need to get the latest version of OpenTX Companion. At the time of writing, version 2.2.0RC12 is the latest. You can get it here.
Once installed, click the Settings icon in the top toolbar and under Application Settings make sure to tick “Use OpenTX firmware nightly builds” to be able to download the firmware and “Use companion nightly builds” to be notified of further companion release candidate updates.
To flash your radio, it needs to be in bootloader mode - pinch the yaw and roll trim switches towards the middle and turn your radio on then connect a mini USB cable.
This is good time to do some backups. The first icon highlighted will backup all your models and settings, the second will give you a copy of your current firmware should you need to roll back.
I also recommend making a copy of everything on the TARANIS_SD drive that mounts to your computer when you connect in bootloader mode especially if you have the Amber sound pack installed.
Ok, update time! Click the Download icon in the top toolbar and click Download FW. If you get an “Unable to check for updates” error message make sure you have made the setting changes mentioned above.
If all goes well, you’ll be asked if you want to install the firmware now, so click Yes. If you have a custom startup screen, this is the time to add it. If you don’t have one and want one, Painless360 has your back!
Once complete, unplug your USB and reboot your radio. You will probably get an “SD Card Warning” because the new firmware is expecting a slightly different file structure. You can get the latest one in a ZIP file here.
Connect back up in bootloader mode and open the TARANIS_SD drive that you backed up earlier. Delete everything except SOUNDS and MODELS then copy the contents of that ZIP file onto the SD card but don’t overwrite SOUNDS and MODELS. If you had any custom images, copy them from the BMP folder in your backup to the new IMAGES folder on the SD card.
Installing the scripts:
While still connected it’s time to install the LUA script that makes all this magic work.
Head over to https://github.com/betaflight/betaflight-tx-lua-scripts/releases and get the latest version of the BF TX LUA Scripts. Extract the ZIP file and you’ll have a folder called SCRIPTS - just drag this over to the SD card and you’re nearly done.
Setting up the radio:
The last steps are done on the radio itself. With your model selected on the Model Selection screen, long press PAGE to get to page 13 of 13 called Display. Scroll down to Screen 1 and change "None" to "Script". In the next field over select "BF". Now exit back out to the main screen.
From this screen, a long press of Page will take you to the PID setup screen. If your quad isn’t on you’ll not get any numbers here and "No Telemetry" will be flashing at the bottom of the screen.
Using the menus:
Now you are up and running all you need to know are the commands.
A quick press of Menu toggles between the 3 pages: PIDs, rates and VTx options.
Navigating between fields is the same as in any other Taranis menu: Plus and minus to move around, enter to edit, plus and minus to increase/decrease and Exit to, well, exit! Holding Menu will give you the option to save your changes or reload the page to undo any changes you’ve just made. Holding down Exit will take you back to the main screen.
And there you have it, PID, Rates and VTx all adjustable from your radio. Please bear in mind this is all still in beta so there may be some glitches and when working with your quad on the bench, always take your props off!
Happy flying!
Simon
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