Pixhawk first connection

• Connect to usb
• Understand LED's
• Write some dronekit code read heartbeat
• Read GPS data with dronekit

Connect to USB

• dmsg

[768651.390811] usb 3-2: Product: PX4 FMU v2.x
[768651.390814] usb 3-2: Manufacturer: 3D Robotics
[768651.390816] usb 3-2: SerialNumber: 0
[768651.391528] cdc_acm 3-2:1.0: ttyACM0: USB ACM device

LED's

• Flashing blue: Disarmed, no GPS lock found
• Flashing green: Disarmed (ready to arm), GPS lock acquired.
• Full list: http://ardupilot.org/plane/docs/common-leds-pixhawk.html

Connect GPS and Compass

• LED go to blinking green
• my GPS led blink with green led's

Dronekit hello

#!/usr/bin/env python
from dronekit import connect, VehicleMode

connection_string = "/dev/ttyACM0"

# Connect to the Vehicle.
print("Connecting to vehicle on: %s" % (connection_string,))
vehicle = connect(connection_string, wait_ready=True)

# Get some vehicle attributes (state)
print "Get some vehicle attribute values:"
print " GPS: %s" % vehicle.gps_0
print " Battery: %s" % vehicle.battery
print " Last Heartbeat: %s" % vehicle.last_heartbeat
print " Is Armable?: %s" % vehicle.is_armable
print " System status: %s" % vehicle.system_status.state
print " Mode: %s" % vehicle.mode.name    # settable

# Close vehicle object before exiting script
vehicle.close()

Read GPS data

#!/usr/bin/env python
from dronekit import connect, VehicleMode
import time

connection_string = "/dev/ttyACM0"

def log_gps(self, name, msg):
    print msg

# Connect to the Vehicle.
print("Connecting to vehicle on: %s" % (connection_string,))
vehicle = connect(connection_string, wait_ready=True)

#vehicle.add_message_listener('GLOBAL_POSITION_INT', log_gps)
vehicle.add_message_listener('GPS_RAW_INT', log_gps)

time.sleep(5)
vehicle.close()

Result

• GPS_RAW_INT: The global position, as returned by the Global Positioning System (GPS). This is NOT the global position estimate of the sytem, but rather a RAW sensor value. See message GLOBAL_POSITION for the global position estimate. Coordinate frame is right-handed, Z-axis up (GPS frame)

GPS_RAW_INT {time_usec : 4246687000, fix_type : 4, lat : 324283000, lon : 350107200, alt : 45700, eph : 98, epv : 171, vel : 14, cog : 23071, satellites_visible : 8}

• GLOBAL_POSITION_INT: fused GPS and accelerometers). The position is in GPS-frame (right-handed, Z-up)

GLOBAL_POSITION_INT {time_boot_ms : 2848710, lat : 324284000, lon : 350107830, alt : 99400, relative_alt : 8000, vx : -17, vy : 9, vz : 8, hdg : 4893}

Reference

• Pixhawk Overview
• LEDs (Pixhawk)
• GLOBAL_POSITION_INT