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As Yet Undiscovered Commands

SMerrony

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It seems that, despite all our efforts thus far, there must be some undiscovered commands for the Tello.

The currently-known commands are listed at Low-Level Protocol on our wiki.

Perhaps we could list here the ones that seem to be missing and see if anyone has any ideas? There are some tantalising gaps in the known message IDs!

My list so far...

  • Disconnect - it seems there should exist a nice way to tell the Tello we are disconnecting
  • Start Motors (without taking off) - the official app seems to be able to do this See below
  • Reset Height - i.e. the high-level height reported in flight data
  • Reset MVO position
  • Reset IMU (eg. for Yaw)
 
Last edited:
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Add on:

- human face tracking and follow movements ( available at atellopilot apps but not in official Tello apps)
- if above function is available, not posibble to activate Follow Me or objects function too.
 
Add on:

- human face tracking and follow movements ( available at atellopilot apps but not in official Tello apps)
- if above function is available, not posibble to activate Follow Me or objects function too.
No - that's not what this is about. Here we are trying to discover some commands that are probably built-in to the Tello firmware, but have not so far been identified.
 
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About
  • Start Motors (without taking off) - the official app seems to be able to do this
There is no separate command, it is activated if the left stick is lower right and right stick is lower left.
FYI, aTelloPilot can do it if the joystick is connected. (It is not possible with OSD stick)
 
About
  • Start Motors (without taking off) - the official app seems to be able to do this
There is no separate command, it is activated if the left stick is lower right and right stick is lower left.
FYI, aTelloPilot can do it if the joystick is connected. (It is not possible with OSD stick)
Do you have any idea what the stick value range is for this to activate? I can't seem to get it to work with a game controller using my Go API.
 
About
  • Start Motors (without taking off) - the official app seems to be able to do this
There is no separate command, it is activated if the left stick is lower right and right stick is lower left.
FYI, aTelloPilot can do it if the joystick is connected. (It is not possible with OSD stick)

I have gotten this to work in the official app, and have tried extensively to replicate it via tellolib. I have tried both coding those positions as well as using joysticks with no luck on either. If aTelloPilot can do it that gives me hope, but since it's not open source we still need to find the command. Maybe @bluejune would be a pal and help us out.

My hope for this feature is that it will allow accurate tracking from the origin point, instead of the position jumping to some random position after auto takeoff.
 
Do you have any idea what the stick value range is for this to activate? I can't seem to get it to work with a game controller using my Go API.

starting motor without taking off is done by sending the stick packet like the following for seconds.
roll, pitch and throttle should be minimum while yaw is maximum.

Code:
User Datagram Protocol, Src Port: 6525, Dst Port: 8889
TELLO_CMD
    SOP   : 0xcc
    SIZE  : 176
    CRC8  : 0x7f
    PACT  : 0x60
    DIR   :  -> TO DRONE
    CMD   : TELLO_CMD_STICK (80)
    SEQ   : 0
    DATASZ: 11
    DATA  : 6c 61 0b 5b 28 0d 06 13 21 45 02
        STICK - roll: 364, pitch: 364, thr: 364, yaw:1684, fastmode:0
    CRC16 : 0x7cec
 
I think that explains why - even with game controllers - my API and some of the others aren't triggering the engine start.

On game controllers, as you move a stick away from one of the major compass points (N, S, E, W) the values go off maximum, i.e SE is not max S + max E but a bit less than max of both. I suspect that proper flight and RC controllers show full deflection at the NE, SE, SW and NW points so that SE generates 100% S + 100% E.

Possible solutions appear to be either a dedicated command in the API to fake the required stick input, or implementing some kind of response curve for the sticks.
 
starting motor without taking off is done by sending the stick packet like the following for seconds.
roll, pitch and throttle should be minimum while yaw is maximum.

How many seconds?

Possible solutions appear to be either a dedicated command in the API to fake the required stick input, or implementing some kind of response curve for the sticks.

I see you got it figured out in your library. Did you fake the stick input somehow? I have tried every combo that has been suggested.
 
I see you got it figured out in your library. Did you fake the stick input somehow? I have tried every combo that has been suggested.
I have done two things, fixed the package (library) to send the FULL range of joystick values as they were accidentally halved before, and changed the app I am working on to always send maximum joystick values when the stick reads over 50% (a crude 'response curve' I suppose). It's working now.
 
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starting motor without taking off is done by sending the stick packet like the following for seconds.
roll, pitch and throttle should be minimum while yaw is maximum.

Code:
CMD   : TELLO_CMD_STICK (80) - roll: 364, pitch: 364, thr: 364, yaw:1684, fastmode:0

@bluejune thanks for the great info! I tried using the same command for shutting off the motors/props without using the LANDING (land) command but it causes the drone to slowly circle down for some time before shutting off the motors.

I am looking for the binary packet equivalent of the SDK 'emergency' command which immediately stops the motors/props.
Do you know what roll, pitch, throttle, and yaw values to send in the TELLO_CMD_STICK message?
 

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