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Understanding how Capture connects

Good Morning Px4D team, I have a technical question that maybe you can help me with. I understand that when using a “phone or table” the phone uses WiFi? to connect to the drone and send the waypoint info prior to take off (is this correct?) 

With that said, upon take off, then drone is not longer controlled by the app and autonomously flying. Theoretically (not that we will) I should be able to turn off the controller and phone and drone will complete the mission?

We were under the impression, more so, when using a device connected to a controller, that it was the controller sending the information and maintaining a link with the UAS.

It is important for me to understand what is happening to be able to have a mitigation plan should something go wrong in the air etc.

In short I would to know how the app communicates with the drone.
PS: I are also using a crystalsky to run the app.

Any answer PIX4D ?
If my tablet or crystal sky is connected via USB to the controller, it is not using wifi but rather the freq. Of the controller which means is stronger and more reliable tham wifi…?

Hi Cesar,

You can plan missions with our app on a mobile device (phone or tablet). Then, for DJI drones, you need to connect it to a remote controller (via Wi-Fi or USB depending on the drone) which will serve as relay to connect to the drone. 

Keep in mind that a connection [mobile device (app)]-[remote controller]-[drone] is required to trigger the image capture.

  • If the connection [mobile device (app)]-[remote controller] is lost (ex: phone is switched off), but the remote controller is still connected to the drone, the drone will continue to fly the mission, going through the waypoints (that information is sent to the remote controller at the start of the mission). However, no pictures will be captured, because the trigger comes from the app.
  • If the connection [remote controller]-[drone] is lost (ex: remote controller switched off), safety procedures defined the DJI GO (4) app will kick in.

It is with the remote controller that you can take over manual control of the drone at anytime during the mission. In the app, you can only use the Abort feature, which triggers the safety procedures defined the DJI GO (4). 

You should find all the necessary information in our Getting Started set of articles for Android or iOS, particularly in step 3. You will also find some safety recommendations.

I hope this helps!

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So is there a wifi connection between the phone and the aircraft even when the phone is connected to the controller ? Think of a DJI Phantom 4 pro. And forget the phone, let use a regular tablet.

What happens if I turn off the wifi ?

my question more directly, if I have wifi turned off on the tablet, and the tablet is connected via USB to the controller (DJI) is the trigger for the photos being sent via the controllers STRONGER/more consistent 2.5ghz signal? 

In the case of DJI Phantom 4 Pro only USB connection between the device and controller is possible. So turning off the Wi-Fi on the device has no impact on the drone or triggering. 

For example, DJI Spark, DJI Phantom 3 Standard, and Parrot Bebob 2 use Wi-Fi to establish the connection between the controller and device, but this is not the case for most drones (also P4P - USB).

As you already mentioned, in the end, default signal (e.g. 2.400 - 2.483 GHz or 5.725 - 5.825 GHz) is used to send the actual command to trigger the images from the controller to the drone. 


I assume that the M200 is triggered via the controller. If you loose momentary connection between the controller and the drone you may not collect those pictures?


There are different picture trigger modes.

  • Android: The action to take a picture is based on a time lapse. 
  • iOS Safe: The drone stops to take every picture which significantly increases the flight time. The way-points where to shoot are uploaded to the drone before starting the mission. This means the drone can fly the mission without requiring a connection with the app.
  • iOS Fast: The app sends a signal to the drone when to take a photo. This mode does not make the drone stop but the connection with the drone should be maintained without interruption. It is solely based on the position of the aircraft.

Gaps in the image acquisition can happen because of connection loss with the Fast mode (iOS).