Discussions

What's the current status of RSSI support on Pixhawk?

Posted by turdsurfer on October 20, 2014 at 12:57pm

I'm been searching and reading (even in Github), but haven't found any definitive answer(s) yet.

Is this something that is already supported or is it in a todo queue somewhere (which I can't find)?

The manual refers to PWM RSSI. Unfortunately, there are 2 flavours of PWM (servo PWM as EzUHF uses for RSSI I believe, and 'normal' PWM as FrSky outputs for RSSI). The manual isn't clear on which it's referring to, or if it's both:

http://copter.ardupilot.com/wiki/common-pixhawk-overview/#Pixhawk_PWM_Connectors_for_Servos_and_ESCs_and_PPM-SUM_in_and_SBUS_out

If it's referring to servo-PWM {

then I must make a RC filter for my FrSky RSSI output

}

else {

just connect it directly.

}

Thanks

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frsky, pwm, pixhawk, rssi

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Replies

Taag July 10, 2015 at 5:01pm

Hi,

I've Frsky x8r and Pixhawk with the lastest firmware on board. Can you explain me how make the connections between the Frsky x8r and the Pixhawk. I know I need a RC filter.

Thank you very much.
Matthias Badaire October 27, 2014 at 1:50pm

There is no code AFAIK in APM for pwm rssi. We read analog voltage, that's it.

Connecting directly might work but most likely there will be delay in the rssi information received by the pixhawk, or it will jump up and down all the time.

Just use a voltmeter on your rssi signal and see what happens, APM will the same thing.

I personally use the RC filter on my D4R, D8R, X8R, X4R..

To be complete, having PWM rssi in APM should be possible and I believe there is a PR in Github for that .. never commited AFAIK
Paul Meier October 24, 2014 at 5:21am

I tried with the Iris, join ch 2 of frsky D4R-II rx to sbus on pixhawk, and it works. By the way I am using arducopter 3.1.5

PS dont forget this: Quote

"Reply by Matthias Badaire on May 13, 2014 at 3:08am

http://copter.ardupilot.com/wiki/common-pixhawk-overview/

Virtual Pin 103: RSSI (Received Signal Strength Input) input pin voltage (SBus connector output pin). This is the voltage measured by the RSSI input pin on the SBUS-out connector (the bottom pin of the 2nd last servo connector on the 14 connector servo rail).

Modify RSSI_PIN to 103

http://copter.ardupilot.com/wiki/arducopter-parameters/#Receiver_RS...

Modify RSSI_RANGE to 5.0

http://copter.ardupilot.com/wiki/arducopter-parameters/#Receiver_RS..."

(I modified RSSI_RANGE to 3.3 and get value rxrssi of up to 99 in MP)
- Esteban Jaramillo > Paul Meier October 26, 2014 at 11:21am
  
  So I already did this and I'm only getting 100%, 75% or 0% in the RSSI
  - Artem > Esteban Jaramillo October 26, 2014 at 1:25pm
    
    Are you using x8r rx? In my case I have a pretty good resolution..... I regularly see values in mid 90, 80, 70 and 60..... Never gone lower though...
Artem October 23, 2014 at 8:06am

Out of my experience, x8r + pixhawk do not need a filter, just plug and play. First read it on the 3.2 beta forum, tried and it works, but have not seen it documented thought.
- Artem > Artem October 23, 2014 at 2:41pm
  
  Do you want me to take a video?
  - Esteban Jaramillo > Artem October 23, 2014 at 2:42pm
    
    it's ok man I just want to know if it's working ok as the guy above wrote it won't register correctly
    - Artem > Esteban Jaramillo October 23, 2014 at 2:52pm
      
      Looking at RSSI on taranis vs rxrssi in MP difference is about 8-9% but I think this is more due to taranis showing its own RSSI i.e. how well it receives the telemetry from x8r (which uses more bandwidth thus introducing more errors) also taranis is on the ground with all the wifi mess and x8r in the semi-clean air, so I think this is a legitimate difference.
- Esteban Jaramillo > Artem October 23, 2014 at 2:36pm
  
  Can anyone confirm this?