Getting the current value of a drone state or setting

In this example, we will be using the get_state() method to query the current value of the “maximum tilt” drone’s setting.

When the maximum tilt drone setting is changed by the controller (Olympe) with the MaxTilt() command message the drone sends the MaxTiltChanged() event message in response. Changing a drone setting will be demonstrated in the following example. Here, we’re just interested in getting the current drone setting.

When Olympe connects to a drone it also asks the drone to send back all its states and settings event messages. Olympe can later provide you with this information through the olympe.Drone.get_state() method. So if Olympe is connected to a drone, olympe.Drone.get_state() always returns the current drone state associated to an event message.

In this case, we will be passing the MaxTiltChanged() message to the olympe.Drone.get_state() method. This will return a dictionary of the MaxTiltChanged() event message which provides the following parameters:

MaxTiltChanged Parameters:

• current (float) – Current max tilt

• min (float) – Range min of tilt

• max (float) – Range max of tilt

Note: Don’t be confused here, the “min” and “max” parameters are actually the minimum and the maximum values for the “maximum tilt” setting. Here, we are only interested in the “current” value of this setting.

Let’s get down to some practice! First, reset the simulation (sphinx-cli action -m world fwman world_reset_all in a terminal).

Create the following Python maxtiltget.py script somewhere in your home directory:

import olympe
import os
from olympe.messages.ardrone3.PilotingSettingsState import MaxTiltChanged

DRONE_IP = os.environ.get("DRONE_IP", "10.202.0.1")


def test_maxtiltget():
    drone = olympe.Drone(DRONE_IP)
    drone.connect()
    print("Drone MaxTilt = ", drone.get_state(MaxTiltChanged)["current"])
    drone.disconnect()


if __name__ == "__main__":
    test_maxtiltget()

To execute this script and see your drone taking off, from the same shell/terminal you’ve just source’d the shell script:

$ python ./maxtiltget.py

This should print the current maximum tilt value in your terminal. The following sequence diagram illustrate what is happening in this simple example.

Getting the drone MaxTilt