BetaFPV Lite Radio 2 - OpenTX 2.3.x
• Chris
The one thing that was annoying me with BetaFPV’s Lite Radio 2 is the power up/down time - you need to press that power button for what feels like an eternity to switch the radio on or off.
Unfortunately with OpenTX 2.2.x you cannot adjust the time needed to press to button to power cycle it, with 2.3.x you can. According to this thread in the Betaflight OpenTX fork you can run 2.3.x without any bigger issues (Big thank you to user knoopx for trying that out).
DISCLAIMER: Before flashing make sure that you meet the following two conditions:
- back up your original firmware and settings, so that you have something you can come back to
- make sure that the Radio is in working order and will actually bind with your model. If it does not bind, chances are that something else is wrong and debugging will be harder - since you will not know if something went wrong during the flash or was wrong from the beginning.
Overview
The Lite Radio 2 seems to be more or less compatible with the Taranis X7. I say more or less, because you can flash the same base firmware, but you will still run into a couple of problems: The Lite Radio obviously has no screen and no SD card slot, less obvious: it does not have a real time clock.
After flashing the radio with 2.3.x, it will power up but the red light will come on. You will have to press the setup button to basically confirm the “RTC check” error which would have normally been shown on the screen if there was one available. Luckily you can disable this behavior and I will show you how.
The only feature you will lose is that the LED will not start blinking once the battery is running low. The transmitter will still start to vibrate, so I do not consider that a big loss.
Updating the Radio
Download and install the OpenTX companion for 2.3.x (at the moment I write this article the latest version is 2.3.9).
Connect your transmitter
Press the setup button on the back of the transmitter and press the power button, no LED will come up, but when you attach it to the computer, you should see a “Taranis” drive appear. The radio is now in bootloader mode you are ready to start the OpenTX companion.
Create a Profile
In the OpenTX companion create a Profile with the “Radio Type” set to FrSky Taranis X7 / X7S. Set the “Profile Name” to something descriptive like “BetaFPV Lite Radio 2”. Leave the Build options as they are.
Set the “Default Stick Mode” to Mode 2 and the “Default Channel Order” to T A E R.
Do not forget to select the newly added profile, in case you have multiple profiles.
Flash the firmware
Click the “Download” button [1] in the top bar of the OpenTX companion, in the following dialog box click “Download firmware” to acquire the latest 2.3.x firmware.
Click the “Write Firmware to Radio” button [2] on the left bar to write the firmware you just downloaded to your BetaFPV Lite 2 Radio.
Update the settings
To update the settings, click the “Read Models and Settings From Radio” button [1] in the left bar of the OpenTX companion. A warning will open up letting you know, that your EEPROM is from a different version. After confirming this, another window will show up, displaying the saved model (AE-SBUS) and general radio settings. In case of the BetaFPV Lite Radio, this will be the only model.
Immediately flash back this updated EEPROM by clicking the “Write Models and Settings” button [2]. Close the settings window and read the settings back again by clicking the “Read Models and Settings From Radio” button [1] one more time.
Click the “Edit Radio Settings Button” [3]. In the “Setup” tab adjust the following settings:
- Show Splash Screen on Startup: —
- Power On Delay: 0 sec
- Power Off Delay: 0 sec
Obviously you can set them to your own preference, those are mine.
In the “Hardware” tab scroll down to “RTC Batt Check” and disable the checkbox. If you leave this enabled, the red LED will come on when you power on the radio and you will have to dismiss the message (that you cannot see) by pressing the setup button on the back of the transmitter.
Close the Radio settings tab.
Double click the model and in the “Setup” tab scroll down to the “External Radio Module” section. Set the protocol to “SBUS output at VBat”, do not touch any other settings in this section, especially the (wrongly shown PPM Frame Length). Close the model window.
Be aware that the OpenTX companion has a bug here: Do not change the “PPM Frame Length” settings here. This setting actually has nothing to do with PPM and will mess up your timings, resulting in your transmitter not transmitting anything useful. Technically this needs to be set to 7ms.
You can right click the model and select “Print Model” to verify that the external module is set to “SBUS output at VBat”, the “Frame length” is at 7ms and the “Polarity” is set to Negative - if you see anything else in this section, your radio will not work properly.
Click “Write Models and Settings to Radio”, and confirm by clicking “Write to TX” in the next window. For the peace of mind I always like to have the “Check Firmware compatibility” active.
You are now basically done. Power off the transmitter by long pressing the power button. After that you can power it on again - if you used my settings it will come on immediately.
Now verify from within the Betaflight configurator that everything is still working in the receiver tab as you would expect it.
Downloads
For your convenience, here are the binary files for your BetaFPV Light Radio:
2.2.4
This are the original firmware and settings files that I dumped from my radio, use those if you want to go back to stock settings.
2.3.9
This are the 2.3.9 OpenTX firmware and my adapted settings.
Chris is a Vienna based software developer. In his spare time he enjoys reviewing tech gear, ripping quads of all sizes and making stuff.
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