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Permalink Reply by Jake Stew on July 18, 2012 at 1:16pm

Lots of posts here state the the xbees aren't fast enough for this sort of thing.  The APM sends a lot of telemetry data, which can cause lag.  Some people were using 2 xbees IIRC.

The 3DR radio is much faster, so I would think it would work a lot better.

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DeveloperPermalink Reply by Andrew Tridgell on July 18, 2012 at 4:59pm

Hi Jesse,
If you try it, please let us know how it goes.
I suspect you may need to play with the radio settings to make it work smoothly. The defaults are meant for reliable long range operation, whereas what you want is low latency. I suspect you will do better running the airspeed at 128, and no ECC. That will give you about 1/4 of the latency of the default settings. The range will be lower, but the responsiveness to joystick control should be better.
Cheers, Tridge

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Permalink Reply by Jesse Knight on July 18, 2012 at 5:46pm

Thanks guys.  I'll give it a try so long as no one has a reason to believe it will not work.  I'm an experienced software guy, but am a total novice when it comes to radios.

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Permalink Reply by James Kirkley on July 18, 2012 at 8:21pm

Talk about coincidence.

I was writing up a separate topic I was going to post and saw this post.

I'm very intreagued about the possibility of this type of setup becoming the RC radio of the future.

 

 

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Permalink Reply by Cliff-E on July 18, 2012 at 9:12pm

Hey Tridge, is someone looking into Xbee failsafe? I briefly looked at 2.6 and was wondering (I have something in 2.5.5 for xbee failsafe, but now porting to MAVLink 1.0).

Cause when you are in rc override mode, if the xbee/3dr/etc.. radio fails or loses comm, the code stays on the last commanded signal and ignores the radio_in sigs. You'll end up losing control--correct me if I'm wrong. So if you were pitching forward on the joystick and lost the Xbee/3DRR, well... you get the picture. This happened to us one time under rc_override and the Tx was 'locked out'-- so it rolled 'away'. Luckily not far and was not high. In the end, not a good situation.

I suggest a quick fix is when the mode changes via channel 5, that the override values are reset to 0/-1, so you can get full Tx control again.

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