Setup for DJI o3 air unit? FPV on rc car

[rotauq]

Then it should not be the esc triggering the failsafe. Failsafe should recover as soon as the signals stabalise.

On this article i saw people posting with simular problems on a regular drone setup
https://oscarliang.com/quad-arming-issue-fix/

Are you powering the air unit via the FC or a directly on the battery? Eventhough the FC was designed to power the air unit it does draw a lot of power when armed. FC BEC could be a little weak and trigger the failsafe

 

[Lennart]

Then it should not be the esc triggering the failsafe. Failsafe should recover as soon as the signals stabalise.

On this article i saw people posting with simular problems on a regular drone setup
https://oscarliang.com/quad-arming-issue-fix/

View attachment 312235

Are you powering the air unit via the FC or a directly on the battery? Eventhough the FC was designed to power the air unit it does draw a lot of power when armed. FC BEC could be a little weak and trigger the failsafe

I did all my current testing without the o3 air unit like on one picture I sent earlier. But O3 works for completely fine when I connect the FC (9v 2.5A)to a lipo.

I only had to cut the o3 SBUS wire so that I could use my Rx SBUS wire. Arming the o3 and all works until the motor physically rotates and I get rxloss.

When I power the Rx with a lipo and only connect the esc signal wire to ch2 it's the same. When I only connect the servo without the esc signal wire I get jumping channels when turning the servo. Did not happen when the esc was connected additionally. However, the disturbence then is not strong enough to trigger a failsafe.

I even powered the RX with a very weak external PSU. The channel jumping even started from the servos power draw in neutral position.

All in all verrrry strange. And I think it has to be PSU noise or signal wire noise or both. I will give the R8FG a chance.

But until I feel like I really need the extra range I will drive unarmed for now...

 

[Mr9Mojave]

But please don't waste too much of your time on this. I have now contacted the radiolink support maybe they can help.

Maybe my FC does not support PPM because when I set it the receiver mode to PPM it just goes back to the last working protocol after reboot. So I cant even try using it.

Maybe I give R8FG v2.1 a try. It only has SBUS output and I hope it processes sbus differently than my R7FG. I have to buy a new one because the first R7FG got stuck in green LED mode and wont bind after I connected the DJI o3 SBUS and the RX SBUS at the same time...

View attachment 312226

View attachment 312228

The orientation of your FC, is it supposed to be on that angle?

Also is it nice and level, and did you calibrate it?

Sounds like it's hitting fail safe..nice clean build though hope you get it working!

 

[Lennart]

The orientation of your FC, is it supposed to be on that angle?

Also is it nice and level, and did you calibrate it?

Sounds like it's hitting fail safe..nice clean build though hope you get it working!

Thanks.

The picture Is just from bench testing the receiver and I unscrewed everything to access the solder pads.

 

[Mr9Mojave]

Thanks.

The picture Is just from bench testing the receiver and I unscrewed everything to access the solder pads.

Ah of course.

Overall whats your video feed like?

Can you just drive it without having your Rx hooked up to the FC?

Maybe just use the FC for telemetry for now and drive it fpv and see how you go.

I'd say there's a very small step left to get it 100% running, could be wanting more power, most new FC's want direct voltage from the lipo but yeah i wish i could help more, it took me ages to get mine running for I'm not the sharpest tool in the shed.

 

[Lennart]

Ah of course.

Overall whats your video feed like?

Can you just drive it without having your Rx hooked up to the FC?

Maybe just use the FC for telemetry for now and drive it fpv and see how you go.

I'd say there's a very small step left to get it 100% running, could be wanting more power, most new FC's want direct voltage from the lipo but yeah i wish i could help more, it took me ages to get mine running for I'm not the sharpest tool in the shed.

Yes you are correct it's already at 80% of what I want it to do. And it took way more time than I thought it would.

Power supply is strong enough though.

And yes these are two Separate systems and when I don't connect the SBUS wire, it works just fine, minus the extra range I get when armed.

The video feed is just stunning, coming from analog. 1080p full HD and OLED screens in the goggles is just insane

 

[Mr9Mojave]

Yes you are correct it's already at 80% of what I want it to do. And it took way more time than I thought it would.

Power supply is strong enough though.

And yes these are two Separate systems and when I don't connect the SBUS wire, it works just fine, minus the extra range I get when armed.

The video feed is just stunning, coming from analog. 1080p full HD and OLED screens in the goggles is just insane

That's great to hear, yeah stepping up to HD digital from analogue is awesome must admit.

 

[rotauq]

Other than budget there is no reason to keep using analog. HD is so much better it's almost silly in comparison.



An other lazy option would be to use a seperate radio/receiver to arm the FC. Or go the arduino road like Mr9Mojave

 

[Lennart]

That's how it looks like when I take a picture through the goggles lenses. The only downside of this Dji system for me really is all the money you have to spend.
And the heat the air unit produces, that you have to arm it to get full output power and how uncomfortable the goggles are with the stock faceplate.

I will give an update in 3 weeks when my R8FG receiver arrives, which could resolve the SBUS issue.

And I will try connecting an old FC to the RX which is the other possible source of error.

 

[Lennart]

So I went out this evening and did some DISARMED range testing and got to about 200 meters with 6Mbps remaining. It was still smooth video and just the picture's edges were looking more like analog video feed.

Still the same SBUS issues with R8FG receiver. So it should be the flight controllers fault. However, I tested 3 of my old FCs and none of them would even show a receiver connection. What is going on. So my newest FC still does best, since it receives sbus until the motor starts turning.....

Straaaaaange

 

[rotauq]

So I went out this evening and did some DISARMED range testing and got to about 200 meters with 6Mbps remaining. It was still smooth video and just the picture's edges were looking more like analog video feed.

Still the same SBUS issues with R8FG receiver. So it should be the flight controllers fault. However, I tested 3 of my old FCs and none of them would even show a receiver connection. What is going on. So my newest FC still does best, since it receives sbus until the motor starts turning.....

Straaaaaange

View attachment 314447

That's a lot better than my vista+v1 goggles. I think i got only up 120m in low power mode.

What range can you actually get from your Radiolink without getting too much input latency? 300m? Before I switched to the noble nb4 i had a lot of trouble with latency at a distance. It's really hard to drive when it reacts with more than a second delay.

 

[Lennart]

That's a lot better than my vista+v1 goggles. I think i got only up 120m in low power mode.

What range can you actually get from your Radiolink without getting too much input latency? 300m? Before I switched to the noble nb4 i had a lot of trouble with latency at a distance. It's really hard to drive when it reacts with more than a second delay.

I will have to test the latency with my Radiolink.
Did not pay attention to that so probably not too bad at 200meters.
Hopefully I don't have to buy a noble radio when I upp the FPV range

 

[Lennart]

That's a lot better than my vista+v1 goggles. I think i got only up 120m in low power mode.

What range can you actually get from your Radiolink without getting too much input latency? 300m? Before I switched to the noble nb4 i had a lot of trouble with latency at a distance. It's really hard to drive when it reacts with more than a second delay.

I am trying to get it working again now by using my drones old FC for the car.

Is it possible to just connect the dji air unit over a random TX and RX pad? I have the newest Betaflight on my old F4 FC.
But SBUS is not even recognized. Do I have to invert the sbus pad or something?

But I also tried the PPM output of the R7FG receiver and it did not work either. I am a little confused...
I obviously used the sbus/PPM and an RX pad to connect the data cable.

 

[rotauq]

I am trying to get it working again now by using my drones old FC for the car.

Is it possible to just connect the dji air unit over a random TX and RX pad? I have the newest Betaflight on my old F4 FC.
But SBUS is not even recognized. Do I have to invert the sbus pad or something?

But I also tried the PPM output of the R7FG receiver and it did not work either. I am a little confused...
I obviously used the sbus/PPM and an RX pad to connect the data cable.View attachment 316902

https://oscarliang.com/dji-fpv-system-setup/

F4 should have a smartport and should not need manual invertion on/off, but if you wanna try:

 

[Lennart]

Could be stupid: what do you need the brown signal ground cable for?
Do I need to connect it on my R7FG too because the receiver itself is not powered by the flight controllers power output?

Maybe I should try powering the RX with my FC 5v output...

https://oscarliang.com/dji-fpv-system-setup/


View attachment 316910
View attachment 316911
View attachment 316912

F4 should have a smartport and should not need manual invertion on/off, but if you wanna try:

View attachment 316913

 

[rotauq]

Could be stupid: what do you need the brown signal ground cable for?
Do I need to connect it on my R7FG too because the receiver itself is not powered by the flight controllers power output?

View attachment 316916

Maybe I should try powering the RX with my FC 5v output...

Definately not a stupid question. Normally i'd say, just a single/dual signal cable should suffice. Considering the weird interferance you were encountering, it might not be a bad idea at all to give them all the same ground. In your Kakute example it's to clean up what ever mess the VRM might make.

 

[Lennart]

Definately not a stupid question. Normally i'd say, just a single/dual signal cable should suffice. Considering the weird interferance you were encountering, it might not be a bad idea at all to give them all the same ground. In your Kakute example it's to clean up what ever mess the VRM might make.

I literally just tested running the R7FG with my FCs 5v pad (so this "signal" ground was connected) and it did the trick (almost), super clean and stutter free sbus channels in betaflight.

But now it seems the stuttering is in the esc signal wire and the motor is not reacting or just randomly turning and stuff. Definitely don't want to test that with my castle motor...

MAÝBE the last question: Do I have to look at the sbus cable as a positive cable with small power flow, which works best paired with a ground cable?
And should I now connect the signal AND ground wire of my esc to the RX in order to keep the signal for the motor clean?
Or does that burn something up?

 

[rotauq]

I literally just tested running the R7FG with my FCs 5v pad (so this "signal" ground was connected) and it did the trick (almost), super clean and stutter free sbus channels in betaflight.

But now it seems the stuttering is in the esc signal wire and the motor is not reacting or just randomly turning and stuff. Definitely don't want to test that with my castle motor...

MAÝBE the last question: Do I have to look at the sbus cable as a positive cable with small power flow, which works best paired with a ground cable?
And should I now connect the signal AND ground wire of my esc to the RX in order to keep the signal for the motor clean?
Or does that burn something up?

Gnd is seen as a common. So it should not be required. But 'common' from different sources can make a difference.
Nothing will burn if you connect grounds from different sources. As long as you keep the positives separated.

 

[Lennart]

Gnd is seen as a common. So it should not be required. But 'common' from different sources can make a difference.
Nothing will burn if you connect grounds from different sources. As long as you keep the positives separated.

And I learned something new. It took just a couple of weeks to install the ground cable additionally to the signal wire.

Its best to use a common ground for all systems....

How small the problems are in reality

 

[rotauq]

Common ground solves so many problems, not just in electronics

So all is working now?