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RSSI from Ch8 (Pixhawk SB connected to RSSI on X8R)

Posted by Paul Atherton on May 6, 2015 at 1:56pm

I have the RSSI (PWM) port of my FrSky X8R Rx connected with a servo cable to the SBUS input of the Pixhawk. I have Pixhawk configured for RSSI input to that port (RSSI_PIN set to 103 in Mission Planner, plus RSSI_RANGE set to 3.3) I have read that its possible to get MinimOSD-Extra to see that RSSI data by configuring its RSSI Channel setting to 'Channel 8'. Well, I have tried this and all I get on the OSD (with RSSI Enable RAW checked) is the PWM value being received on Channel 8 within Pixhawk, not the RSSI value as I appear to need to make this work. I know this is the PWM value I am seeing because if I set a switch to ch8 on my Tx, I can see this value change with changes in switch position, so Channel 8 is definitely getting through to the OSD, but its not displaying the RSSI value.

Logic says that there should be some configuration within Mission Planner to configure the Pixhawk to reflect the RSSI value on the Telemetry accessed 'Channel 8', but I have been searching within MP and on the Net, with no results.

Can the developer of MinimOSD-Extra please advise if there is a way to get this PWM data from within Pixhawk onto the OSD please?? (incidentally, the RSSI value is accessible within Pixhawk on the variable called RXRSSI, and it does accurately mimic the value on my Taranis radio. Maybe MinimOSD-Extra just needs to make this variable available to the OSD. Just an idea instead of using channels to get at it.

Cheers, Paul

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Tags: frsky, minimosd-extra, rssi, rxrssi, x8r
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Replies

  • Jim Calvert March 22, 2017 at 5:43am

    Hi Paul,

    My apologies, I should have added the links.  Here are the two most important:

    http://diydrones.ning.com/forum/topics/config-tool-questions-for-mi...

    http://diydrones.ning.com/forum/topics/mavlink-ods-battery-a-b-conf...

    Please do not spend undue time on them but if you have some hints, that would be really appreciated.

    Jim Calvert


    Jim Calvert said:

    Hi Paul,

    Clearly you know a fair amount about this OSD.

    So I have a favour to ask.  I have 3 other topics in the OSD forum that no one has touched in several days.

    Is there any chance that you might look at them please.

    For you they are probably trivial.

    Many thanks

    Jim Calvert



    Paul Atherton said:


    Jim,

    You can have OpenTx assign the RSSI to any channel you like, and then have Ardupilot listen to the chosen channel by configuring the RSSI_CHANNEL paramater to suit. This will allow Ardupilot to send out that RSSI value on the telemetry stream and you can choose the option in MinimOSD for Mavlink RSSI instead of Ch8 - so should be able to access that via the Mavlink telemetry stream instead of directly from the channel.

    Hope this helps. Cheers, Paul
    Jim Calvert said:

    Now I have a request; do you know any way to set this up using something other than Ch8.  The MinimOSD forces me to use ONLY Ch8.  I don't think the Taranis will put out the RSSI value on a pin (just a channel).  Please correct me if not so.

    Thanks

    Jim Calvert

  • Paul Atherton March 22, 2017 at 12:52am

    Jim,

    Links to those 3 topics please?

    To be honest, I rarely use MinimOSD these days - the RSSI choices it has are the same on most OSDs. My OSD of choice is PlayUAV OSD - its a graphics OSD rather than text, and there are a small group of guys who have taken over continued development of this project since the original developer (Tom Ren) disappeared. The chat about PlayUAV OSD is here: http://fpvlab.com/forums/showthread.php?40658-A-Graphics-OSD-for-AP...


    Jim Calvert said:

    Hi Paul,

    Clearly you know a fair amount about this OSD.

    So I have a favour to ask.  I have 3 other topics in the OSD forum that no one has touched in several days.

    Is there any chance that you might look at them please.

    For you they are probably trivial.

    Many thanks

    Jim Calvert

  • Jim Calvert March 21, 2017 at 6:48pm

    Hi Paul,

    Clearly you know a fair amount about this OSD.

    So I have a favour to ask.  I have 3 other topics in the OSD forum that no one has touched in several days.

    Is there any chance that you might look at them please.

    For you they are probably trivial.

    Many thanks

    Jim Calvert



    Paul Atherton said:


    Jim,

    You can have OpenTx assign the RSSI to any channel you like, and then have Ardupilot listen to the chosen channel by configuring the RSSI_CHANNEL paramater to suit. This will allow Ardupilot to send out that RSSI value on the telemetry stream and you can choose the option in MinimOSD for Mavlink RSSI instead of Ch8 - so should be able to access that via the Mavlink telemetry stream instead of directly from the channel.

    Hope this helps. Cheers, Paul
    Jim Calvert said:

    Now I have a request; do you know any way to set this up using something other than Ch8.  The MinimOSD forces me to use ONLY Ch8.  I don't think the Taranis will put out the RSSI value on a pin (just a channel).  Please correct me if not so.

    Thanks

    Jim Calvert

  • Paul Atherton March 19, 2017 at 1:30pm


    Jim,

    You can have OpenTx assign the RSSI to any channel you like, and then have Ardupilot listen to the chosen channel by configuring the RSSI_CHANNEL paramater to suit. This will allow Ardupilot to send out that RSSI value on the telemetry stream and you can choose the option in MinimOSD for Mavlink RSSI instead of Ch8 - so should be able to access that via the Mavlink telemetry stream instead of directly from the channel.

    Hope this helps. Cheers, Paul
    Jim Calvert said:

    Now I have a request; do you know any way to set this up using something other than Ch8.  The MinimOSD forces me to use ONLY Ch8.  I don't think the Taranis will put out the RSSI value on a pin (just a channel).  Please correct me if not so.

    Thanks

    Jim Calvert

  • Jim Calvert March 19, 2017 at 12:50pm

    Hi Paul,

    Many thanks for putting out this note.

    I followed your specs and it worked 1st time.

    I use a Pixhawk with roughly the latest Rover software and Taranis plus radio and X8R receives and a MinimOSD Extra.

    Now I have a request; do you know any way to set this up using something other than Ch8.  The MinimOSD forces me to use ONLY Ch8.  I don't think the Taranis will put out the RSSI value on a pin (just a channel).  Please correct me if not so.

    Thanks

    Jim Calvert



    Paul Atherton said:

    Hey Robert,

    Not sure what version of AP you are running, but on 3.4 there are a lot more RSSI parameters. This is a section cut from my saved parameters file (actually this is from my Plane running 3.5.2, but the same settings are present in 3.4-RC1, and I have this working on my quad using this version):

    RSSI_ANA_PIN,0
    RSSI_CHAN_HIGH,2012
    RSSI_CHAN_LOW,988
    RSSI_CHANNEL,8
    RSSI_PIN_HIGH,0
    RSSI_PIN_LOW,0
    RSSI_TYPE,2

    The last setting suggests that the RSSI value is read from the PWM value of a channel - as you can see, its Ch8 in my case.

    Once that's done and you have your Taranis setup to output the RSSI on Ch8 (or whatever you choose) you should see the value appear against rxrssi in Mission Planner.

    To setup the Taranis, on the Inputs page (within your model screens) choose an input and set one up with the source as RSSI (this is using the telemetry RSSI sensor), all other settings are default, so save this (lets say for argument sake, this is i8). Then on the mixer screen set Ch8 (or whatever you want) to use the input you setup (so i8), but also change the offset to -100 and the weight to 200. That should do it. You can add the rxrssi value to the HUD display if you want.

  • Robert July 11, 2016 at 8:45pm

    Hello Paul,

    Thanks for the info. I might use the beta just to see the OSD on the screen and then would probably put it back to 3.3 until 3.4 is stable.



    Paul Atherton said:

    Robert said:

    Hello Paul,

    I am using APM 3.3 and couldn't find the 3.4 on Mission planner when I am trying to upgrade the firmware. It kept saying the latest is 3.3.3?

    Are you using APM plane?

    3.4 is available through the Beta button on Mission Planner - RC1 (means Release Candidate 1), so use at your own risk.

    I use both Plane and Copter.
  • Paul Atherton July 10, 2016 at 11:23pm

    Robert said:

    Hello Paul,

    I am using APM 3.3 and couldn't find the 3.4 on Mission planner when I am trying to upgrade the firmware. It kept saying the latest is 3.3.3?

    Are you using APM plane?

    3.4 is available through the Beta button on Mission Planner - RC1 (means Release Candidate 1), so use at your own risk.

    I use both Plane and Copter.
  • Robert July 10, 2016 at 8:45pm

    Hello Paul,

    I am using APM 3.3 and couldn't find the 3.4 on Mission planner when I am trying to upgrade the firmware. It kept saying the latest is 3.3.3?

    Are you using APM plane?



    Paul Atherton said:

    Hey Robert,

    Not sure what version of AP you are running, but on 3.4 there are a lot more RSSI parameters. This is a section cut from my saved parameters file (actually this is from my Plane running 3.5.2, but the same settings are present in 3.4-RC1, and I have this working on my quad using this version):

    RSSI_ANA_PIN,0
    RSSI_CHAN_HIGH,2012
    RSSI_CHAN_LOW,988
    RSSI_CHANNEL,8
    RSSI_PIN_HIGH,0
    RSSI_PIN_LOW,0
    RSSI_TYPE,2

    The last setting suggests that the RSSI value is read from the PWM value of a channel - as you can see, its Ch8 in my case.

    Once that's done and you have your Taranis setup to output the RSSI on Ch8 (or whatever you choose) you should see the value appear against rxrssi in Mission Planner.

    To setup the Taranis, on the Inputs page (within your model screens) choose an input and set one up with the source as RSSI (this is using the telemetry RSSI sensor), all other settings are default, so save this (lets say for argument sake, this is i8). Then on the mixer screen set Ch8 (or whatever you want) to use the input you setup (so i8), but also change the offset to -100 and the weight to 200. That should do it. You can add the rxrssi value to the HUD display if you want.

  • Paul Atherton July 10, 2016 at 4:16pm

    Hey Robert,

    Not sure what version of AP you are running, but on 3.4 there are a lot more RSSI parameters. This is a section cut from my saved parameters file (actually this is from my Plane running 3.5.2, but the same settings are present in 3.4-RC1, and I have this working on my quad using this version):

    RSSI_ANA_PIN,0
    RSSI_CHAN_HIGH,2012
    RSSI_CHAN_LOW,988
    RSSI_CHANNEL,8
    RSSI_PIN_HIGH,0
    RSSI_PIN_LOW,0
    RSSI_TYPE,2

    The last setting suggests that the RSSI value is read from the PWM value of a channel - as you can see, its Ch8 in my case.

    Once that's done and you have your Taranis setup to output the RSSI on Ch8 (or whatever you choose) you should see the value appear against rxrssi in Mission Planner.

    To setup the Taranis, on the Inputs page (within your model screens) choose an input and set one up with the source as RSSI (this is using the telemetry RSSI sensor), all other settings are default, so save this (lets say for argument sake, this is i8). Then on the mixer screen set Ch8 (or whatever you want) to use the input you setup (so i8), but also change the offset to -100 and the weight to 200. That should do it. You can add the rxrssi value to the HUD display if you want.

  • Robert July 10, 2016 at 3:41pm

    Hello Paul,

    How do you configure Mission Planner to read the RSSI? I only found this RSSI on Mission Planner?

    Where can I find the RXRSSI variable? Thanks

    3702266016?profile=original



    Paul Atherton said:

    No. I found that the Pixhawk  SBUS port (when configured as per my original post) is only capable of reading an analog input for RSSI on this port (I.e. voltage from 0 to 3.3v), but the output from the X8R is not analog, but advertised as PWM, so not directly compatible. If it were pure PWM, then it should be possible to convert the output to an analog signal to make it compatible, but from what I have read, the PWM output is not a regular PWM output on that RSSI port, so I didn't find a way to use it directly. I did however find an alternate solution to the original problem - I.e. a way to get RSSI through to the OSD.

    My solution is to configure the Taranis to put the RSSI value onto a spare channel, and have the Pixhawk configured to read the RSSI from this channel. This is then accessible in Mission Planner in the RxRSSI variable. This is also accessible on the OSD by configuring it either one of two ways - either:

    1. By having that RSSI sent through Channel 8 and configuring the OSD to access the RSSI on channel 8

    2. By configuring the OSD to access the RSSI from Mavlink data

    Both of these work.

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