Discussions

Hi guys,

I'm using a Pixhawk with latest AC3.2-rc10 in combination with an FrSky X8R connected over SBUS and have been trying to get the rssi signal read from the receiver and monitoring it with Mission Planner for a while now, but I still can't get it working. Maybe you'll be able to help my figure out a solutionm to this.

I checked the signal on the rssi output of the receiver with an oscilloscope and despite the fact, that the Frsky manual claims the rssi to output an analog voltage (0..3.3 V), it seems to be a kind of PWM Signal (square wave signal with about 90% high level and 10% low level). So I made a low pass filter with a 1K resistor and 10 µF capacitor, smoothening the signal to an analog voltage of about 3,1 volts.

Moreover I set the correct parameters in my pixhawk

RSS_PIN 103

RSSI_RANGE 3,3 (the German version of MP seems to require "," instead of "." otherwise it interprets the "3.3" as "33")

and connected the rssi output of the X8R to the SBUS labeled port on the pixhawk, which in the wiki is stated to be the default rssi input pin of the pixhawk.

But in Mission Planner the rssi-value under the "status"-tab remains 0, no matter what the input voltage on pin 103 is. I also tested this with directly feeding an analog voltage into pin 103, but did not see any changes. Setting the RSSI_RANGE parameter to 5 also had no effect on this.

Do you have any ideas, what could be wrong with my setup? Or is the rssi code disabled in AC3.2? I read, that PWM rssi will be supported in a future realese of AC, but analog rssi should be working right now. Is that correct?

Thanks and have a nice day.

Lukas