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Apr 09, 2017, 12:52 PM
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Quote:
Originally Posted by Lanza View Post
Sorry I have only used it with PPM. But I would not be surprised if pin 3 is used for SBUS too, and pin 4 for RSSI. I am using this as reference: http://hypomaniac.co.uk/passing-rssi-x8r-pixhawk/
Anybody check it have the RSSI input??
Last edited by Arkbox; Aug 21, 2017 at 08:48 AM.
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Aug 23, 2017, 03:27 AM
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Pin 3 is common input for PPM or SBUS.

Pin 4 is analog RSSI input. You can set the voltage range 0-3.3V or 0-5V in the Mission Planner.

If you want to feed common PWM format RSSI (1-2ms), leave pin 4 open and enter in the Mission Planner the receiver channel number which carries the PWM. I have tested a Frsky XM+ with PWM signal on ch16 and it works just fine.

I love this micropix more and more.
Last edited by hobbya; Aug 23, 2017 at 04:08 AM.
Aug 24, 2017, 01:06 AM
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Quote:
Originally Posted by hobbya View Post
Pin 3 is common input for PPM or SBUS.

Pin 4 is analog RSSI input. You can set the voltage range 0-3.3V or 0-5V in the Mission Planner.

If you want to feed common PWM format RSSI (1-2ms), leave pin 4 open and enter in the Mission Planner the receiver channel number which carries the PWM. I have tested a Frsky XM+ with PWM signal on ch16 and it works just fine.

I love this micropix more and more.
This information is not available in any source, are you sure about analog RCCI input 4? Or it only teoretical?
about PWM I know, but seems Frsky X8R has not Sbus RSSI output. I dont find it.

And what about last versions upgrade?? I can't upgrade to 3.5~
Aug 24, 2017, 01:12 AM
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I have tested it myself.
RSSI is pin 4 (you need to set RSSI_ANA_PIN to 103 on Mission Planner)
Receiver tested: XM+ (need to flash a FW on Frsky website which supports ch16 PWM RSSI)
FW on micropix: v3.5.1 (upgraded from stock v3.1.5 via Mission Planner)

X8R is different from XM+. It has embedded telemetry and a dedicated RSSI output pin. However the RSSI output is high frequency PWM which requires a RC filter to change it to analog RSSI voltage (0-3.3V varying according to signal strength).

XM+ has no embedded telemetry but can transmit standard PWM RSSI over ch8 or ch16 by flashing the appropriate FW. It also has a RSSI output pad but it does not work well (0V for no RX signal and 3.3V for whatever RX signal strength) .
Last edited by hobbya; Aug 28, 2017 at 01:31 AM.
Aug 24, 2017, 03:40 AM
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mpjf01's Avatar
Quote:
Originally Posted by hobbya View Post
flashing the appropriate FW. It also has a RSSI output pad but it does not work well (0V for no RX signal and 3.3V for whatever RX signal strength) .
Is this with the 170313 version?
Aug 24, 2017, 04:20 AM
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Quote:
Originally Posted by mpjf01 View Post
Is this with the 170313 version?
Exactly. The package contains a load of different FW's. I have picked "XM+FCC170313-RSSI16.frk" for my experiment.
Aug 24, 2017, 05:02 AM
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mpjf01's Avatar
I might try the version without the RSSI channel then in the hope that FRSKY believes that those using RSSI output on a channel wouldn't need the pad output and so didn't bother fixing that. I've been reluctant to flash my second XM+ having had the first lockup during the flash and stay that way.
Aug 24, 2017, 05:12 AM
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The green LED on XM+ turns steadily on for a good signal and blinks when rx starts to drop packets. I have hoped to use this as the analog RSSI instead of the 'useless' RSSI pad but it just will not work properly after verifying on an oscilloscope.
To get a reliable RSSI from XM+, PWM on ch8 or ch16 is the only way.
Last edited by hobbya; Aug 28, 2017 at 01:31 AM.
Aug 24, 2017, 05:38 AM
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I have an XM+ coming but I was wondering about taking the RSSI directly from ch16 in sbus as mentioned by JC RIP. Is this possible with the ardupilot software ?
RSSI With FrSky XM & XM Plus (6 min 36 sec)
Aug 24, 2017, 09:16 AM
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Quote:
Originally Posted by Lanza View Post
I have an XM+ coming but I was wondering about taking the RSSI directly from ch16 in sbus as mentioned by JC RIP. Is this possible with the ardupilot software ?
Arducopter version later than v3.5 can take PWM input over RC channel. This implies the FC must be Pixhawk as APM can only work up to v3.2.1.

Below is what I have tested successfully:
1) display RxRSSI on Mission Planner
2) display on MinimOSD by feeding PWM RSSI directly to OSD board
3) display on MWOSD by feeding PWM RSSI directly to OSD board

What I want to do next is to see if Arducopter can send RSSI to OSD board via Mavlink. Up to the moment only 0% and 100% can be displayed and I still do not know how to improve. I appreciate support from other hobbyists.
Last edited by hobbya; Aug 24, 2017 at 09:55 PM.
Aug 24, 2017, 09:09 PM
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I will not have the chance to test this in a while but I was wondering if you tried to map the RSSI into a channel to get it into the SBUS stream or is that a different type of RSSI or the XM+ is not capable of doing that?

I am looking at https://pixhawk.org/users/rc_rssi
Aug 24, 2017, 09:55 PM
Registered User
It is confident that pixhawk can decode the RSSI mapped into a rc channel on sbus because Mission Planner can display the strength properly.

Displaying on the OSD is another story since it depends on the Mavlink communication between pixhawk and OSD. If I can figure this out I can save some hardware and wirings in my new quadcopter build. I want my new quad as compact as possible.
Aug 24, 2017, 10:22 PM
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Maybe you can setup the channel as a passthrough http://diydrones.com/group/arducopte...Group%3A394475

And in night_ghost's minimosd show the raw value of the channel. Is not RSSI but it can give you a number.
Aug 24, 2017, 11:37 PM
Registered User
I confirm everything is ok. Pixhawk can pass the RSSI over Mavlink to either MinimOSD or MWOSD.

Attached is my setting to display RSSI on Mission Planner and pass PWM RSSI via Mavlink to OSD.

I obtained the PWM range by using a SBUS-to-PWM converter as well as an oscilloscope. One might also write codes to obtain the values. Some good reference here.
Last edited by hobbya; Aug 25, 2017 at 09:25 PM.
Aug 25, 2017, 11:04 AM
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Quote:
Originally Posted by hobbya View Post
I confirm everything is ok. Pixhawk can pass the RSSI over Mavlink to either MinimOSD or MWOSD.

Attached is my setting to display RSSI on Mission Planner and pass PWM RSSI via Mavlink to OSD.

I obtained the PWM range by using a SBUS-to-PWM converter as well as an oscilloscope. However I believe using the stock values (2000 and 1000) should still work fine.
This is fantastic!
Thank you!


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