MAVLink Protocol

MAVLink v2 Frame:

+-----+-----+-----+-----+--------+--------+---------+------+-------+
| STX | LEN | SEQ | SYS | COMP   | MSG ID | PAYLOAD | CRC  | SIG   |
| FD  |     |     | ID  | ID     | (3B)   |         | (2B) | (13B) |
+-----+-----+-----+-----+--------+--------+---------+------+-------+

Common message types:
- HEARTBEAT (0): System alive indicator
- SET_MODE (11): Change flight mode
- COMMAND_LONG (76): Execute command
- MISSION_ITEM (39): Waypoint data
- RC_CHANNELS_OVERRIDE (70): Override RC input

# pymavlink - Python MAVLink library
pip install pymavlink

from pymavlink import mavutil

# Connect to telemetry radio
conn = mavutil.mavlink_connection('/dev/ttyUSB0', baud=57600)

# Or UDP connection
conn = mavutil.mavlink_connection('udp:127.0.0.1:14550')

# Wait for heartbeat
conn.wait_heartbeat()
print(f"System {conn.target_system} Component {conn.target_component}")

# Arm the vehicle (dangerous!)
conn.mav.command_long_send(
    conn.target_system, conn.target_component,
    mavutil.mavlink.MAV_CMD_COMPONENT_ARM_DISARM,
    0, 1, 0, 0, 0, 0, 0, 0
)

# Force landing
conn.mav.command_long_send(
    conn.target_system, conn.target_component,
    mavutil.mavlink.MAV_CMD_NAV_LAND,
    0, 0, 0, 0, 0, 0, 0, 0
)