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#!/usr/bin/env python
# -*- coding: utf-8 -*-
© Copyright 2015-2016, 3D Robotics.
Demonstrates how to get and set vehicle state and parameter information,
and how to observe vehicle attribute (state) changes.
Full documentation is provided at
from __future__ import print_function
from dronekit import connect, VehicleMode
import time
#Set up option parsing to get connection string
import argparse
parser = argparse.ArgumentParser(description='Print out vehicle state information. Connects to SITL on local PC by default.')
help="vehicle connection target string. If not specified, SITL automatically started and used.")
args = parser.parse_args()
connection_string = args.connect
sitl = None
#Start SITL if no connection string specified
if not connection_string:
import dronekit_sitl
sitl = dronekit_sitl.start_default()
connection_string = sitl.connection_string()
# Connect to the Vehicle.
# Set `wait_ready=True` to ensure default attributes are populated before `connect()` returns.
print("\nConnecting to vehicle on: %s" % connection_string)
vehicle = connect(connection_string, wait_ready=True)
# Get all vehicle attributes (state)
print("\nGet all vehicle attribute values:")
print(" Autopilot Firmware version: %s" % vehicle.version)
print(" Major version number: %s" % vehicle.version.major)
print(" Minor version number: %s" % vehicle.version.minor)
print(" Patch version number: %s" % vehicle.version.patch)
print(" Release type: %s" % vehicle.version.release_type())
print(" Release version: %s" % vehicle.version.release_version())
print(" Stable release?: %s" % vehicle.version.is_stable())
print(" Autopilot capabilities")
print(" Supports MISSION_FLOAT message type: %s" % vehicle.capabilities.mission_float)
print(" Supports PARAM_FLOAT message type: %s" % vehicle.capabilities.param_float)
print(" Supports MISSION_INT message type: %s" % vehicle.capabilities.mission_int)
print(" Supports COMMAND_INT message type: %s" % vehicle.capabilities.command_int)
print(" Supports PARAM_UNION message type: %s" % vehicle.capabilities.param_union)
print(" Supports ftp for file transfers: %s" % vehicle.capabilities.ftp)
print(" Supports commanding attitude offboard: %s" % vehicle.capabilities.set_attitude_target)
print(" Supports commanding position and velocity targets in local NED frame: %s" % vehicle.capabilities.set_attitude_target_local_ned)
print(" Supports set position + velocity targets in global scaled integers: %s" % vehicle.capabilities.set_altitude_target_global_int)
print(" Supports terrain protocol / data handling: %s" % vehicle.capabilities.terrain)
print(" Supports direct actuator control: %s" % vehicle.capabilities.set_actuator_target)
print(" Supports the flight termination command: %s" % vehicle.capabilities.flight_termination)
print(" Supports mission_float message type: %s" % vehicle.capabilities.mission_float)
print(" Supports onboard compass calibration: %s" % vehicle.capabilities.compass_calibration)
print(" Global Location: %s" % vehicle.location.global_frame)
print(" Global Location (relative altitude): %s" % vehicle.location.global_relative_frame)
print(" Local Location: %s" % vehicle.location.local_frame)
print(" Attitude: %s" % vehicle.attitude)
print(" Velocity: %s" % vehicle.velocity)
print(" GPS: %s" % vehicle.gps_0)
print(" Gimbal status: %s" % vehicle.gimbal)
print(" Battery: %s" % vehicle.battery)
print(" EKF OK?: %s" % vehicle.ekf_ok)
print(" Last Heartbeat: %s" % vehicle.last_heartbeat)
print(" Rangefinder: %s" % vehicle.rangefinder)
print(" Rangefinder distance: %s" % vehicle.rangefinder.distance)
print(" Rangefinder voltage: %s" % vehicle.rangefinder.voltage)
print(" Heading: %s" % vehicle.heading)
print(" Is Armable?: %s" % vehicle.is_armable)
print(" System status: %s" % vehicle.system_status.state)
print(" Groundspeed: %s" % vehicle.groundspeed) # settable
print(" Airspeed: %s" % vehicle.airspeed) # settable
print(" Mode: %s" % # settable
print(" Armed: %s" % vehicle.armed) # settable
# Get Vehicle Home location - will be `None` until first set by autopilot
while not vehicle.home_location:
cmds = vehicle.commands
if not vehicle.home_location:
print(" Waiting for home location ...")
# We have a home location, so print it!
print("\n Home location: %s" % vehicle.home_location)
# Set vehicle home_location, mode, and armed attributes (the only settable attributes)
print("\nSet new home location")
# Home location must be within 50km of EKF home location (or setting will fail silently)
# In this case, just set value to current location with an easily recognisable altitude (222)
my_location_alt = vehicle.location.global_frame
my_location_alt.alt = 222.0
vehicle.home_location = my_location_alt
print(" New Home Location (from attribute - altitude should be 222): %s" % vehicle.home_location)
#Confirm current value on vehicle by re-downloading commands
cmds = vehicle.commands
print(" New Home Location (from vehicle - altitude should be 222): %s" % vehicle.home_location)
print("\nSet Vehicle.mode = GUIDED (currently: %s)" %
vehicle.mode = VehicleMode("GUIDED")
while not'GUIDED': #Wait until mode has changed
print(" Waiting for mode change ...")
# Check that vehicle is armable
while not vehicle.is_armable:
print(" Waiting for vehicle to initialise...")
# If required, you can provide additional information about initialisation
# using `vehicle.gps_0.fix_type` and ``.
#print "\nSet Vehicle.armed=True (currently: %s)" % vehicle.armed
#vehicle.armed = True
#while not vehicle.armed:
# print " Waiting for arming..."
# time.sleep(1)
#print " Vehicle is armed: %s" % vehicle.armed
# Add and remove and attribute callbacks
#Define callback for `vehicle.attitude` observer
last_attitude_cache = None
def attitude_callback(self, attr_name, value):
# `attr_name` - the observed attribute (used if callback is used for multiple attributes)
# `self` - the associated vehicle object (used if a callback is different for multiple vehicles)
# `value` is the updated attribute value.
global last_attitude_cache
# Only publish when value changes
if value!=last_attitude_cache:
print(" CALLBACK: Attitude changed to", value)
print("\nAdd `attitude` attribute callback/observer on `vehicle`")
vehicle.add_attribute_listener('attitude', attitude_callback)
print(" Wait 2s so callback invoked before observer removed")
print(" Remove Vehicle.attitude observer")
# Remove observer added with `add_attribute_listener()` specifying the attribute and callback function
vehicle.remove_attribute_listener('attitude', attitude_callback)
# Add mode attribute callback using decorator (callbacks added this way cannot be removed).
print("\nAdd `mode` attribute callback/observer using decorator")
def decorated_mode_callback(self, attr_name, value):
# `attr_name` is the observed attribute (used if callback is used for multiple attributes)
# `attr_name` - the observed attribute (used if callback is used for multiple attributes)
# `value` is the updated attribute value.
print(" CALLBACK: Mode changed to", value)
print(" Set mode=STABILIZE (currently: %s) and wait for callback" %
vehicle.mode = VehicleMode("STABILIZE")
print(" Wait 2s so callback invoked before moving to next example")
print("\n Attempt to remove observer added with `on_attribute` decorator (should fail)")
vehicle.remove_attribute_listener('mode', decorated_mode_callback)
print(" Exception: Cannot remove observer added using decorator")
# Demonstrate getting callback on any attribute change
def wildcard_callback(self, attr_name, value):
print(" CALLBACK: (%s): %s" % (attr_name,value))
print("\nAdd attribute callback detecting ANY attribute change")
vehicle.add_attribute_listener('*', wildcard_callback)
print(" Wait 1s so callback invoked before observer removed")
print(" Remove Vehicle attribute observer")
# Remove observer added with `add_attribute_listener()`
vehicle.remove_attribute_listener('*', wildcard_callback)
# Get/Set Vehicle Parameters
print("\nRead and write parameters")
print(" Read vehicle param 'THR_MIN': %s" % vehicle.parameters['THR_MIN'])
print(" Write vehicle param 'THR_MIN' : 10")
print(" Read new value of param 'THR_MIN': %s" % vehicle.parameters['THR_MIN'])
print("\nPrint all parameters (iterate `vehicle.parameters`):")
for key, value in vehicle.parameters.iteritems():
print(" Key:%s Value:%s" % (key,value))
print("\nCreate parameter observer using decorator")
# Parameter string is case-insensitive
# Value is cached (listeners are only updated on change)
# Observer added using decorator can't be removed.
def decorated_thr_min_callback(self, attr_name, value):
print(" PARAMETER CALLBACK: %s changed to: %s" % (attr_name, value))
print("Write vehicle param 'THR_MIN' : 20 (and wait for callback)")
for x in range(1,5):
#Callbacks may not be updated for a few seconds
if vehicle.parameters['THR_MIN']==20:
#Callback function for "any" parameter
print("\nCreate (removable) observer for any parameter using wildcard string")
def any_parameter_callback(self, attr_name, value):
print(" ANY PARAMETER CALLBACK: %s changed to: %s" % (attr_name, value))
#Add observer for the vehicle's any/all parameters parameter (defined using wildcard string ``'*'``)
vehicle.parameters.add_attribute_listener('*', any_parameter_callback)
print(" Change THR_MID and THR_MIN parameters (and wait for callback)")
## Reset variables to sensible values.
print("\nReset vehicle attributes/parameters and exit")
vehicle.mode = VehicleMode("STABILIZE")
#vehicle.armed = False
#Close vehicle object before exiting script
print("\nClose vehicle object")
# Shut down simulator if it was started.
if sitl is not None: