udp frames starting with 0xcc, data is 12 or 13 bytes long - what is this?

[martinpi]

On Wireshark, I see frames like this one:



192.168.0.3 is my PC.
192.168.0.0 is Tello.

The frames with a data length of roughly 160 are the stat frames. "mid:-1;x:0;y:0..."
Then there are the frames which I send, like "go 0 0 0 25 20"
and the frames which I expect, like "ok".

And inbetween, roughly every half second, there are these frames like the one in the picture.
What does that mean?

 

[pgminin]

You have low level protocol decoded in the wiki section here:

Low-Level Protocol

A lot of collaborative effort has taken place via these forums to decode the low-level protocol that the Tello uses to communicate with its native app. We will try to gather the information that has been obtained together on these pages. The Tello communicates with its controller via Wifi on a...

tellopilots.com

Message ID is in bytes 5-6 (little endian), in this case 0x0035 ... its Light Strenght!

 

[martinpi]

You have low level protocol decoded in the wiki section here:

Low-Level Protocol

A lot of collaborative effort has taken place via these forums to decode the low-level protocol that the Tello uses to communicate with its native app. We will try to gather the information that has been obtained together on these pages. The Tello communicates with its controller via Wifi on a...

tellopilots.com

Message ID is in bytes 5-6 (little endian), in this case 0x0035 ... its Light Strenght!

Thanks a lot!

When I am not mistaken, there is a way to send and receive information that is not covered in the SDK.
This information is not encoded in ASCII characters, is this correct?

I found this on the web: "https://github.com/SMerrony/tello/blob/master/ImplementationChart.md"
(where I find 00 35 = light strength. And many others)

 

[f41ardu]

Thanks a lot!

When I am not mistaken, there is a way to send and receive information that is not covered in the SDK.
This information is not encoded in ASCII characters, is this correct?

I found this on the web: "https://github.com/SMerrony/tello/blob/master/ImplementationChart.md"
(where I find 00 35 = light strength. And many others)

That is the low level protocol, there are GO and C# implementations available. I tried to implement this using Processing make some progress but still struggling with getting flightdata and Video, too.

The Processing language is based on Java.

Example:

public byte[] land()
  {
    byte[] packet =  { byte(0xcc), byte(0x60), byte(0x00), byte(0x27), byte(0x68), byte(0x55), byte(0x00), byte(0xe5), byte(0x01), byte(0x00), byte(0xba), byte(0xc7) };

    //payload
    packet[9] = 0x00;//todo. Find out what this is for.
    setPacketSequence(packet);
    setPacketCRCs(packet);
    return packet;
  }
...
......
 /** 
  /*
  /*  document me
  */
  public byte[]setMaxHeight(int height)
  {
     //                                                         crc         typ         cmdL        cmdH        seqL        seqH        heiL        heiH       crc          crc
     byte[] packet = { byte(0xcc), byte(0x68), byte(0x00), byte(0x27), byte(0x68), byte(0x58), byte(0x00), byte(0x00), byte(0x00), byte(0x00), byte(0x00),byte(0x5b) , byte(0xc5) };

     //payload
     packet[9] = (byte)(height & 0xff);
     packet[10] = (byte)((height >>8) & 0xff);

     setPacketSequence(packet);
     setPacketCRCs(packet);

     return (packet);
  }