Please explain - Litchi App

[DanMan32]

It has to be in range at some point in the orbit (POI) to start the orbit so it should be in range at least periodically.
Then again you can change the radius while it is orbiting so I suppose you could end up out of range for the entire radius.
But you should then be able to physically move closer to get back the signal. It can't be that far out of range.
It is a concern that smart RTH is disabled. That should be left as an option so that it does come back but doesn't unduly defeat the purpose of POI that has no end.

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[dan84uk]

IMO, not really dangerous at all if you're aware of its limitations. There are two simple ways to avoid it getting stuck in an orbit if it loses contact:

1. Don't use orbit if there's a chance of the bird getting out of range (or move closer to the orbit area if you can),

2. Set it up as a waypoint mission where YOU program the orbit points and radius. That way, if it loses contact it'll continue the mission anyway and fly back to you as programmed in your mission.

Or just use DJI GO and have it RTH. Perfect. I consider Orbit to be broken in Litchi

You cant plan for control interference, you can only minimize the chances of it happening with the variables you can control. Anyone can suffer signal loss at any moment through no fault of there own. ( It happened to me) And when it happens and it starts landing off the side of a cliff into the sea, you are going to wish you used GO.

Ill continue using both, selecting the appropriate app for each scenario.

 

[TopDawg]

nice video

 

[dwcola]

Personal Experience: Litchi has worked flawlessly every time I've used it. Have had hundreds of flights both fpv manual and waypoint. It does return to home or hover based on selection if signal is lost. I stopped using GO since I use a Samsung Galaxy (doesn't allow multiple apps without creating issues). The only thing I need with GO that Litchi does not offer are the Gain and Expo settings, however, if those are set correctly, typically I do not need to change unless I want very slow moving shots with lazy expo settings.

 

[tribar]

I have purchased the Litchi app due to the many positive comments on this forum.
I have a P3S which I added itelite range extender to. (Not impressed so far)
I started reading the manual for Litchi and if I am understanding this app,.....if I loose the signal, the RTH feature does not work. The Phantom 3 Standard will just hover. Did I understand this correctly? Because if this is true,.....then the app is a no go for me.
If I misunderstood the manual,....can you explain under what circumstances the P3S would not RTH with Litchi,....VS DJI Go?
Thank you in advance for you time and answers.


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You're absolutely correct, it will hover, but:
Only with the Phantom 3 standard AND only in FPV mode.
This is a limitation/bug in the DJI SDK.

 

[DanMan32]

Are you sure about that?
Some features are stored and executed by the AC, some stored/executed by the app. Some I would suspect stored/hsndled by the RC. RC expo/gain for example I would expect the RC and AC to take care of once set.
No signal response definitely with the AC since on disconnect, there's no way for the app to tell these AC what to do.
Autonomous flight such as POI and waypoint would be totally in AC's control including what to do on signal loss regardless of app.
I suspect POI will just keep going, waypoint execute fail-safe once mission completes.
Critical battery (10% default setting) should land.
Smart RTH on the other hand could go either way as to what component executes (app or AC) and if it would trigger on missions.
If a feature is totally AC dependant to execute, then app used wouldn't matter unless the app can tell/program the AC how to handle mission interruption on conditions.


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[Solly747400]

But not if your flying a waypoint mission or track mode.

I have flown a waypoint mission far beyond my range and it completed the mission. Went out 2.5kms and came back and landed

 

[tribar]

There used to be a warning for this on Litchi's help-page written in red. It's not there anymore so maybe DJI fixed this in a SDK update.
Also gimbal-pitch calculations are executed by the smart device, not by the AC. So if you loose connection during a waypoint mission and have some "Focus Poi" actions, they will NOT work.

 

[Solly747400]

Also gimbal-pitch calculations are executed by the smart device, not by the AC. So if you loose connection during a waypoint mission and have some "Focus Poi" actions, they will NOT work.

Are you sure? It is my understanding that the whole mission with all it's settings/parameters are loaded to the aircraft, as I said earlier, my litchi mission completed while out of range and took pics and a video of 2 focus points, one of them being at the furtherest point of the mission, 2.5kms away. My range is around 900m tops

 

[tribar]

YES, Yaw is calculated and executed by the AC, gimbal-pitch is calculated by the smart device.

 

[Solly747400]

Yaw is calculated and executed by the AC, gimbal-pitch is calculated by the smart device.

Like I said, it worked for me and I definately don't have 2.5kms range

 

[tribar]

When there's only a few degrees of vertical difference between the Pois and the AC you won't probebly notice it, but gimbal-pitch is definitely not gonna change after you loose connection.
Here's a good example, the 2 houses don't stay in the middle of the frame:

 

[tribar]

To get a good understanding how to use Litchi, visit:
Phantom Filmschool

 

[CRF319]

Are you sure? It is my understanding that the whole mission with all it's settings/parameters are loaded to the aircraft, as I said earlier, my litchi mission completed while out of range and took pics and a video of 2 focus points, one of them being at the furtherest point of the mission, 2.5kms away. My range is around 900m tops

Copied from - Help - Litchi
Waypoint Gimbal Pitch
Litchi can control the gimbal pitch automatically during the mission, as long as the aircraft is within range of the remote controller.

 

[tribar]

Copied from - Help - Litchi
Waypoint Gimbal Pitch
Litchi can control the gimbal pitch automatically during the mission, as long as the aircraft is within range of the remote controller.

This also applies to flying speed !
This can affect the duration of a mission in a negative way.

 

[gvsukids]

But using interpolate allows the gimbal to adjust within flight outside of control range


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[tribar]

But using interpolate allows the gimbal to adjust within flight outside of control range


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NO, it's the same thing.
But... Take it or leave it.

 

[dwallersv]

I did a bit of research about the app and found it can some how damage the battery.

You found completely bogus information. It is complete horse manure.

 

[dwallersv]

Thanks everyone. I do not think I want an app that does not return to home after a mission regardless of which mission I choose.
I purchased this app for possible longer range as my itelite is lucky to get me 3/4 of a mile in range. I can see I will probably be purchasing a P4 with 4K or a P3P very shortly for better range. Also would like to have Fat Shark goggles should I choose to fly FPV.

I think you're misunderstanding the RTH limitations with Litchi. These issues are with features that are not available on DJI GO [4] -- just don't use them (Focus, Orbit).

Focus and Orbit are not unattented features. They're not really even properly called "missions". They require connection to the RC and direct, interactive monitoring to start and stop the "mission". So, there should never be a situation where you're flying either of these features and are not right there with the AC basically LOS, able to take control if something goes wrong.

Rather, the sort of missions you seems to have pointed you to Litchi for are Waypoint Missions. These are uploaded to the AC when started, and can run autonomously when disconnected. End-of-mission behavior is flexible (land, return home, reverse course back to first WP, etc.).

Litchi will do exactly what you want, unless what you wanted to do was fly to a remote location at potential range limit of the control signal, and run an Orbit. However, in that case, just go there and run the Orbit.

 

[dwallersv]

Not for the faint of heart, but something I did to get myself comfortable with RTH and the autonomous mission features.

Grab the Reynolds Wrap and make a foil cover for your RC antennas. Took 3 sheets thickness to completely attenuate the signal so I could "disconnect" from the AC with it sitting on the ground a few feet away.

Go to a flat, very big, wide-open field. Somewhere you can easily get a good distance beyond 20m away horizontally, but still see the AC, and if it drops straight down and lands, fine.

Take off and head away 100 feet or so. Stay low -- 10-20 feet.

Cover your antennas, and watch the fun.

Rinse and repeat again and again, with different settings (come home, hover in place, land immediately, etc.). Do it within 20m circle of the homepoint too, just to see how this works differently. Try it all out with a simple Litchi mission too.

I spent a few hours and 3 batteries doing this one afternoon. It accomplished two important things: 1) I trust this mechanism much more now, as I've seen it work over and over; 2) I'm very familiar with all its ins and outs, and have a heightened awareness to check on my settings every time I fly because all that repetition has fixed this in my thinking unconsciously as "something important".

I would recommend NOT to simply turn your RC off to simulate the loss of contact. If something goes wrong with the method above, you can pull the "hat" off your RC antenna and re-establish contact pretty quickly.