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https://github.com/jaqxues/TelloPython

Normal and reverse engineered ("advanced") Python Api for Tello
https://github.com/jaqxues/TelloPython

reverse-engineering tello tello-python3 tellodrone

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Normal and reverse engineered ("advanced") Python Api for Tello

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README 

        
# TelloPython

*Allows to control your Tello Drone via Python.* 



In addition to the "official" and documented APIs, TelloPython also supports also a number of reverse engineered 

function, such as "Flip", which are not in mentioned in the documentation, and only accessible through the App. Have a

look [demo.py](demo.py), a small script to control the drone with your keyboard, which is not possible with the 

documented APIs (using reverse engineered Joystick Controls).



This Readme also goes through the Basics of how the Tello App was reverse engineered and a basic breakdown on how the

app works.



# Introduction to reverse engineering



## Basics

* The Tello App does not send Strings (e. g. "land" or "takeoff" to the Drone). Instead it sends Command Ids to the 

  drone (shorts). To find the ids:

* The `SocketPacketEntitiy` class contains different fields that you need to figure out before sending any command. To

  log the values of the arguments, I used the Xposed Framework (though you can probably figure it out with Wireshark):

    * cmdId: int

    * data: byte[]

    * pactype: int

    * seqnum: short

    * version: int



## How to find these Command Ids etc

* In the Tello App, the raw ids can be found in classes extending `com.ryzerobotics.tello.gcs.core.cmd.e`. (You can run

  the scripts in `dev_utils.py` to find Command Ids used in comparisons. These script need a decompiled Tello Folder

  (preferably from Jadx). A more complete list (still maybe not all ids) can be found in `cmd_ids`

* You should be able to figure out some Commands by having a look at the class `com.ryzerobotics.tello.gcs.core.cmd.c`

  ("ZOCmdStore")

* By setting the Tello Application to `UserDebuggable` you can use the "Android Layout Inspector" and figure out the ids

  of the buttons and search for their `onClickListener` (done to find `flip` command)

* With Xposed, you can hook every method of the classes extending `e`. Check what Id gets sent when using different

  features. (Takeoff, land etc.). A simpler way (less complete) would be hooking the before mentioned"ZOCmdStore" class.

* Similarly, you can hook the constructor of the class `com.ryzerobotics.tello.gcs.core.c` ("ZOCmdParser") and log 

  the `cmdId` field of the result of method `com.ryzerobotics.tello.gcs.ui.bean.SocketPacketEntity a(byte[], int)`. 

  Note that the `byte[]` sometimes contains useful information in form of text.



## Using different commands



###  The Joystick command

The joystick is handled by `com.ryzerobotics.tello.gcs.core.cmd.d.a(int, int, long, long, long)`

Values are set using Commands in "ZOCmdSendManager". Chinese names for the values are mentioned in log statements with 

tag "yaogan" - "Joystick"). You can understand their meaning by Trial and Error or hooking the Tello App and seeing

what values are passed to the method when using the Joystick in app.



| Chinese names | Directions                   | Name     |

| ------------- |:-----------------------------| :--------|

| zuoYou        | right - left                 | roll     |

| qianHou       | forward - backward           | pitch    |

| shangXia      | up - down                    | throttle |

| xuanZhan      | clockwise - counterclockwise | yaw      |



The last `long` argument does not have a specific name. This `speed_mode` variable is either 0 (slow mode) or 1 (quick 

mode). The values of the other arguments are ints between 364 - 1684 (both included).



* Min (movement on corresponding axis): 364

* ...

* Normal (no movement on corresponding axis): 1024

* ...

* Max (movement on corresponding axis): 1684



Speed per axis given by `abs(1024 - x)`. Direction on axis given by `x > 1024`



## The Flip command

The Flip command takes an int (0 <= int <= 7) to set the direction. 0, 1, 2, 3 are front-, left-, back-, right-flip

respectively. Values 4, 5, 6, 7 are for diagonal flips.