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I've seen several tutorials for the Taranis for outputting RSSI on a channel back up to the RX for use there by a flight controller. For example:

https://github.com/cleanflight/cleanflight/issues/748

I would like to do this on my 9XR Pro running OpenTX, but I can't figure out how. If I go to Mixes -> Channel X -> Source, RSSI is not listed as a potential source.

Since FrSky RSSI (for example) is available to OpenTX, is there any reason this can't be enabled for more than the Taranis? Or is there something I'm missing?

Mapping of telemetry sources onto channels is done in the "Inputs" layer, but that is only available on the Taranis, it was never implemented for the "small LCD" platforms.

What's the purpose of doing that though?

The original firmware on the 'PRO (ersky9x) does support this function.

Mike.

Kilrah wrote:Mapping of telemetry sources onto channels is done in the "Inputs" layer, but that is only available on the Taranis, it was never implemented for the "small LCD" platforms.

What's the purpose of doing that though?

In the case I'm dealing with, FrSky RSSI is notoriously hard to read off the RX pins and convey in a readable format to a MinimOSD or a flight controller, even with various electronic filters. I've struggled with it unsuccessfully for hours, trying various filters, and so have many others. Most of the people I talk to about it say not to bother, even on a scope the signalling doesn't make any sense, and if you have a Taranis, send it back up to the RX on a channel in a format that the flight controller can understand. It's kind of an absurd hack but at this point I'll do what it takes.

Would it be especially tough to implement an RSSI Source for the "small LCD" platforms? Should I attempt a patch, or are there going to be inherent roadblocks/moral objections that make this difficult?

stewlg wrote: It's kind of an absurd hack but at this point I'll do what it takes.

OK. My point is that it may not be very useful as I'd imagine when it starts being interesting (bad reception) the link may be too broken for the info to go back and forth reliably enough to warn you of the problem.

stewlg wrote: Would it be especially tough to implement an RSSI Source for the "small LCD" platforms? Should I attempt a patch, or are there going to be inherent roadblocks/moral objections that make this difficult?

No objection of course, porting the inputs system to sky9x/9XR would sure be welcome. I only had an extremely quick look but I think the only missing thing is the GUI stuff, the background processing seems to already be modular and a #define is all that would be required to enable it.

Of course it would need to target a major version (2.1) as introducing it would break compatibility with current setups.

stewlg wrote:

Kilrah wrote: Would it be especially tough to implement an RSSI Source for the "small LCD" platforms? Should I attempt a patch, or are there going to be inherent roadblocks/moral objections that make this difficult?

Did you get anywhere with this? I'm struggling with the exact same issue. This might be the thing that finally makes me break down and buy a Taranis.

Old topic, but wanted to share my experience, in case others are searching for this also. Recently ran into this post (TNX João!) explaining how to get this to work, and after a lot of trial & error, i now have my 9XR PRo & FrSky X4RSB displaying RSSI in my goggles (Micro MinimOSD) and Telemetry on the screen. Only connections i made between the Rx and FC is the Smarport connection for Telemetry. I took an Rx & Tx from an UART, soldered them together and connected them to the Smartport of the X4RSB)

This is how i got it to work with:

1. Go into your Mixer and configure a Channel (for example 8) as follows:
Source: SC1 (Scaler 1)
Weight: 100
Offset: -100 (without the Offset it won't drop below 50% RSSI, related to the input signal expected to be 1000-2000 instead of 1500-2000)
Fix Offset: ON
Use Output: OFF
Trim: OFF

2. Now go into Model Setup >> Limits >> Check the 'min' and 'max' values of the Channel number (CH8 in this example) you just configured, and make sure the limits go from -100 (min) to 100 (max).

3. Finally go into Model Setup >> Globals >> Scalers >> and setup Scaler1 as follows:
Source: RSSI
Name: RSSI (or whatever you want to name it)
Offset: 0
Multiplier: 20
Divisor: 1
Unit: Pcent
Sign: +
Decimals: 0
Offset At: First

That's what gives me spot on RSSI in Cleanflight/Betaflight GUI, compared to the Telemetry output on the screen. Don't forget to set the RSSI Channel in the Receiver tab.
Betaflight tip: Something to keep in mind is that F1 FCs have 4 AUX channels enabled by default, and F3 FCs have 6 AUX channels enabled by default.
So if you're not getting any output, make sure you have enough AUX channels enabled. Configurable with the CLI command 'set max_aux_channels = X' where X defines the number of channels enabled. AUX channels are limited by default, so save CPU power for the FC.

For the Micro MinimOSD i had to tweak the min/max settings a bit (default 0-1023):
RSSI MIN: 500
RSSI MAX: 985

Enjoy!

That method is for ersky9x, not openTx, which is what the original poster requested.
Using a Scaler for this is one of the reasons I added them, they act as a method to "route" data.

Mike.

Arf... Missed OpenTX...
My bad

On the topic OpenTX 2.2 will have inputs on the 9XR-Pro and other ARM-based 128x64 radios, so it will be possible for them too.