MAVLink

https://mavlink.io/en/
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### Compile the C++ example

Source: https://mavlink.io/en/mavgen_cpp/example_cpp_udp.html

Build the example using cmake with the local installation path.

```sh
cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=$(pwd)/../../install
cmake --build build
```

--------------------------------

### Run the UDP example

Source: https://mavlink.io/en/mavgen_cpp/example_cpp_udp.html

Execute the compiled binary to start listening for MAVLink messages.

```sh
./build/udp_example
```

--------------------------------

### Navigate to examples directory

Source: https://mavlink.io/en/mavgen_cpp/example_cpp_udp.html

Change the working directory to the C++ examples folder.

```sh
cd examples/cpp
```

--------------------------------

### Run Illuminator Emulator

Source: https://mavlink.io/en/services/illuminator.html

Starts the illuminator emulator. Ensure Python 3 is installed.

```bash
python3 illuminator.py
```

--------------------------------

### MAVLink Bridge and System Components

Source: https://mavlink.io/en/services/image_transmission.html

Example commands to start essential components for MAVLink communication and system control on a MAV.

```bash
px_mavlink_bridge_udp &
px_system_control --heartbeat &
px_camera -o lcm &

```

--------------------------------

### Install Custom Pymavlink Libraries

Source: https://mavlink.io/en/mavgen_python/index.html

Install the generated MAVLink libraries for a custom dialect locally using the setup program.

```shell
python setup.py install --user
```

--------------------------------

### Compile C UDP Example with CMake

Source: https://mavlink.io/en/mavgen_c/example_c_udp.html

Compile the C UDP example using CMake, specifying the installation path for MAVLink. Ensure you are in the correct directory.

```sh
cd examples/c
cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=$(pwd)/../../install
cmake --build build
```

--------------------------------

### Example output

Source: https://mavlink.io/en/mavgen_cpp/example_cpp_udp.html

Expected terminal output when the example successfully connects to an autopilot.

```sh
~/github/mavlink/mavlink/examples/cpp$  ./build/udp_example

Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
...
```

--------------------------------

### Install Python 3 and Pip on Ubuntu

Source: https://mavlink.io/en/getting_started/installation.html

Ensure Python and Pip are installed on Ubuntu Linux before proceeding with MAVLink installation.

```bash
sudo apt install python3 python3-pip
```

--------------------------------

### MAV_CMD_MISSION_START (300)

Source: https://mavlink.io/en/messages/common.html

Start running a mission.

```APIDOC
## MAV_CMD_MISSION_START (300)

### Description
Start running a mission.

### Parameters
- **Param 1 (First Item)** - The first mission item to run
- **Param 2 (Last Item)** - The last mission item to run
```

--------------------------------

### Run C UDP Example

Source: https://mavlink.io/en/mavgen_c/example_c_udp.html

Execute the compiled C UDP example. By default, it listens on localhost:14550. Ensure a MAVLink-compatible system (like PX4 or ArduPilot) is running and publishing to this address.

```sh
./build/udp_example
```

--------------------------------

### Install Standard Pymavlink

Source: https://mavlink.io/en/mavgen_python/index.html

Install the standard MAVLink dialect libraries for MAVLink 1 and 2 using pip.

```shell
pip install pymavlink
```

--------------------------------

### MAV_CMD_START_RX_PAIR (500)

Source: https://mavlink.io/en/messages/common.html

Starts receiver pairing.

```APIDOC
## MAV_CMD_START_RX_PAIR (500)

### Description
Starts receiver pairing.

### Parameters
- **RC Type** (enum) - RC type.
- **RC Sub Type** (enum) - RC sub type.
```

--------------------------------

### Install MAVLink Headers with CMake

Source: https://mavlink.io/en/mavgen_c

Installs MAVLink headers locally into an 'install' directory using CMake. This allows subsequent projects to find and use the library.

```shell
cmake -Bbuild -H. -DCMAKE_INSTALL_PREFIX=install -DMAVLINK_DIALECT=common -DMAVLINK_VERSION=2.0
cmake --build build --target install
```

--------------------------------

### Example MAVLink Mission Plain-Text File

Source: https://mavlink.io/en/file_formats/index.html

An example of a mission file adhering to the QGC WPL format. Each line represents a waypoint with its associated parameters, separated by tabs.

```plaintext
QGC WPL 110
0	1	0	16	0.149999999999999994	0	0	0	8.54800000000000004	47.3759999999999977	550	1
1	0	0	16	0.149999999999999994	0	0	0	8.54800000000000004	47.3759999999999977	550	1
2	0	0	16	0.149999999999999994	0	0	0	8.54800000000000004	47.3759999999999977	550	1
```

--------------------------------

### MAV_CMD_VIDEO_START_CAPTURE (2500)

Source: https://mavlink.io/en/messages/common.html

Starts video recording.

```APIDOC
## MAV_CMD_VIDEO_START_CAPTURE (2500)

### Description
Starts video capture (recording).

### Parameters
- **Param 1 (Stream ID)** (uint8) - Required - Video Stream ID (0 for all streams).
- **Param 2 (Status Frequency)** (float) - Required - Frequency CAMERA_CAPTURE_STATUS messages should be sent while recording (Hz).
- **Param 3 (Target Camera ID)** (uint8) - Required - Target camera ID (0: all, 1-6: autopilot-connected, 7-255: MAVLink component id).
```

--------------------------------

### C UDP Example Output

Source: https://mavlink.io/en/mavgen_c/example_c_udp.html

This output shows the successful execution of the C UDP example, indicating that HEARTBEAT messages are being sent and received from a PX4 autopilot on localhost.

```sh
~/github/mavlink/mavlink/examples/c$  ./build/udp_example

Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
Sent heartbeat
Got heartbeat from PX4 autopilot
...
```

--------------------------------

### MAV_CMD_VIDEO_START_STREAMING (2502)

Source: https://mavlink.io/en/messages/common.html

Starts video streaming.

```APIDOC
## MAV_CMD_VIDEO_START_STREAMING (2502)

### Description
Start video streaming.

### Parameters
- **Param 1 (Stream ID)** (uint8) - Required - Video Stream ID (0 for all streams, 1 for first, 2 for second, etc.).
- **Param 2 (Target Camera ID)** (uint8) - Required - Target camera ID (0: all, 1-6: autopilot-connected, 7-255: MAVLink component id).
```

--------------------------------

### Install Required Python Packages

Source: https://mavlink.io/en/getting_started/installation.html

Install the necessary Python packages for MAVLink by referencing the requirements file in the pymavlink directory.

```bash
python3 -m pip install -r pymavlink/requirements.txt
```

--------------------------------

### Build with Local MAVLink Installation

Source: https://mavlink.io/en/mavgen_cpp/index.html

Command to point CMake to the local installation directory of the MAVLink headers.

```sh
cd ../my_program
cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=../mavlink/install
```

--------------------------------

### MAV_CMD_LOGGING_START (2510)

Source: https://mavlink.io/en/messages/common.html

Request to start streaming logging data over MAVLink.

```APIDOC
## MAV_CMD_LOGGING_START (2510)

### Description
Request to start streaming logging data over MAVLink.

### Parameters
- **Param 1 (Format)** (int) - Required - Format: 0: ULog
- **Param 2-7** (int) - Reserved (set to 0)
```

--------------------------------

### Start Image Streamer Component

Source: https://mavlink.io/en/services/image_transmission.html

Command to start the image streaming component on the MAV. The -v flag provides verbose output.

```bash
px_imagestreamer
# or with verbose output:
px_imagestreamer -v
```

--------------------------------

### Initialize MAVLink Parsing Variables

Source: https://mavlink.io/en/mavgen_cpp/index.html

Setup code for status, message, and channel variables required for parsing.

```cpp
#include <mavlink/common/common.hpp>

mavlink::mavlink_status_t status;
mavlink::mavlink_message_t message;
int chan = mavlink::MAVLINK_COMM_0;
```

--------------------------------

### Example Translation Summary JSON

Source: https://mavlink.io/en/services/component_information.html

An example of a translation summary JSON file, showing entries for French (fr_FR) and German (de_DE) locales with their respective translation file URLs and modification dates.

```json
{
  "fr_FR": {
    "url": "https://raw.githubusercontent.com/PX4/PX4-Metadata-Translations/main/translated/parameters_fr_FR.ts.xz",
    "last-modified": "2023-03-22T06:15:59.203476+00:00"
  },
  "de_DE": {
    "url": "https://raw.githubusercontent.com/PX4/PX4-Metadata-Translations/main/translated/parameters_de_DE.ts.xz",
    "last-modified": "2023-03-22T06:15:59.199476+00:00"
  }
}
```

--------------------------------

### MAV_CMD_DO_RETURN_PATH_START (188)

Source: https://mavlink.io/en/messages/common.html

Mission item to specify the start of a failsafe/landing return-path segment.

```APIDOC
## MAV_CMD_DO_RETURN_PATH_START (188)

### Description
Mission item to specify the start of a failsafe/landing return-path segment. A vehicle using missions for landing will join the mission on the closest path of the return-path segment.

### Parameters
- **Param 5 (Latitude)**: Latitude. 0: not used.
- **Param 6 (Longitude)**: Longitude. 0: not used.
- **Param 7 (Altitude)**: Altitude (m). 0: not used.
```

--------------------------------

### MAV_CMD_DO_LAND_START (189)

Source: https://mavlink.io/en/messages/common.html

Mission item to mark the start of a mission landing pattern, or a command to land with a mission landing pattern.

```APIDOC
## MAV_CMD_DO_LAND_START (189)

### Description
When used in a mission, this is a marker for the start of a sequence of mission items that represent a landing pattern. When sent as a command it triggers a landing using a mission landing pattern.

### Parameters
- **Param 5 (Latitude)**: Latitude for landing sequence selection, or 0.
- **Param 6 (Longitude)**: Longitude for landing sequence selection, or 0.
- **Param 7 (Altitude)**: Altitude (m) for landing sequence selection, or 0.
```

--------------------------------

### Build MAVLink Locally with CMake

Source: https://mavlink.io/en/mavgen_c/example_c_udp.html

Use CMake to install MAVLink locally. This sets up the necessary build environment for MAVLink components.

```sh
cmake -Bbuild -H. -DCMAKE_INSTALL_PREFIX=install
cmake --build build --target install
```

--------------------------------

### SETUP_SIGNING (256)

Source: https://mavlink.io/en/messages/common.html

Configures a MAVLink2 signing key.

```APIDOC
## SETUP_SIGNING (256)

### Description
Setup a MAVLink2 signing key. If called with secret_key of all zero and zero initial_timestamp will disable signing.

### Parameters
- **target_system** (uint8_t) - System ID of the target.
- **target_component** (uint8_t) - Component ID of the target.
- **secret_key** (uint8_t[32]) - Signing key.
- **initial_timestamp** (uint64_t) - Initial timestamp.
```

--------------------------------

### Enum Definition Example

Source: https://mavlink.io/en/guide/xml_schema.html

Example of how to define an enum with multiple entries, including descriptions for the enum and each entry. This specific example defines LANDING_TARGET_TYPE.

```xml
<enum name="LANDING_TARGET_TYPE">
    <description>Type of landing target</description>
    <entry value="0" name="LANDING_TARGET_TYPE_LIGHT_BEACON">
        <description>Landing target signaled by light beacon (ex: IR-LOCK)</description>
    </entry>
    <entry value="1" name="LANDING_TARGET_TYPE_RADIO_BEACON">
        <description>Landing target signaled by radio beacon (ex: ILS, NDB)</description>
    </entry>
    <entry value="2" name="LANDING_TARGET_TYPE_VISION_FIDUCIAL">
        <description>Landing target represented by a fiducial marker (ex: ARTag)</description>
    </entry>
    <entry value="3" name="LANDING_TARGET_TYPE_VISION_OTHER">
        <description>Landing target represented by a pre-defined visual shape/feature (ex: X-marker, H-marker, square)</description>
    </entry>
</enum>
```

--------------------------------

### Setup Message Signing with mavutil

Source: https://mavlink.io/en/mavgen_python/message_signing.html

Use the `setup_signing` method from `mavutil` to configure message signing for a connection. This method allows specifying a secret key, whether to sign outgoing messages, a callback for unsigned messages, an initial timestamp, and a link ID. If `link_id` or `initial_timestamp` are not provided, they are handled internally.

```python
#Setup signing
def setup_signing(self, secret_key, sign_outgoing=True, allow_unsigned_callback=None, initial_timestamp=None, link_id=None)
```

--------------------------------

### Install tcpdump on Linux

Source: https://mavlink.io/en/guide/wireshark.html

Installs the tcpdump utility on Debian-based Linux systems. This tool is used for capturing network traffic.

```bash
apt update
apt install tcpdump
```

--------------------------------

### Configure Signing with Custom Unsigned Message Callback

Source: https://mavlink.io/en/mavgen_python/message_signing.html

Set up message signing using `mavutil.setup_signing`, providing a custom `allow_unsigned_callback` function to control which unsigned messages are accepted. This example allows `RADIO_STATUS` messages.

```python
# Assuming you already have a connection set up
the_connection = mavutil.mavlink_connection(...)

# Create a callback to specify the messages to accept
def my_allow_unsigned_callback(self,msgId):
    #Allow radio status messages
    if msgId==mavutil.mavlink.MAVLINK_MSG_ID_RADIO_STATUS:
        return True
    return False

# Pass the callback  to the connection (here we also pass an arbitrary secret key)
secret_key = chr(42)*32
the_connection.setup_signing(secret_key, sign_outgoing=True, allow_unsigned_callback=my_allow_unsigned_callback)
```

--------------------------------

### MAVLink Enum Definition Example

Source: https://mavlink.io/en/guide/define_xml_element.html

This example defines the LANDING_TARGET_TYPE enum, which specifies different types of landing targets with descriptive entries and values.

```xml
<enum name="LANDING_TARGET_TYPE">
    <description>Type of landing target</description>
    <entry value="0" name="LANDING_TARGET_TYPE_LIGHT_BEACON">
        <description>Landing target signaled by light beacon (ex: IR-LOCK)</description>
    </entry>
    <entry value="1" name="LANDING_TARGET_TYPE_RADIO_BEACON">
        <description>Landing target signaled by radio beacon (ex: ILS, NDB)</description>
    </entry>
    <entry value="2" name="LANDING_TARGET_TYPE_VISION_FIDUCIAL">
        <description>Landing target represented by a fiducial marker (ex: ARTag)</description>
    </entry>
    <entry value="3" name="LANDING_TARGET_TYPE_VISION_OTHER">
        <description>Landing target represented by a pre-defined visual shape/feature (ex: X-marker, H-marker, square)</description>
    </entry>
```

--------------------------------

### Find MAVLink Dependency in CMakeLists.txt

Source: https://mavlink.io/en/mavgen_c

Configures a CMake project to find the installed MAVLink library and link it to an executable. Requires the MAVLink installation prefix to be set.

```cmake
find_package(MAVLink REQUIRED)

add_executable(my_program my_program.c)

target_link_libraries(my_program PRIVATE MAVLink::mavlink)
```

--------------------------------

### MAVLink Message Definition Example

Source: https://mavlink.io/en/guide/define_xml_element.html

Example of a MAVLink message definition for 'SAFETY_SET_ALLOWED_AREA'. It shows the structure with ID, name, description, and fields with their types, names, and units.

```xml
<message id="54" name="SAFETY_SET_ALLOWED_AREA">
      <description>Set a safety zone (volume), which is defined by two corners of a cube. This message can be used to tell the MAV which setpoints/waypoints to accept and which to reject. Safety areas are often enforced by national or competition regulations.</description>
      <field type="uint8_t" name="target_system">System ID</field>
      <field type="uint8_t" name="target_component">Component ID</field>
      <field type="uint8_t" name="frame" enum="MAV_FRAME">Coordinate frame. Can be either global, GPS, right-handed with Z axis up or local, right handed, Z axis down.</field>
      <field type="float" name="p1x" units="m">x position 1 / Latitude 1</field>
      <field type="float" name="p1y" units="m">y position 1 / Longitude 1</field>
      <field type="float" name="p1z" units="m">z position 1 / Altitude 1</field>
      <field type="float" name="p2x" units="m">x position 2 / Latitude 2</field>
      <field type="float" name="p2y" units="m">y position 2 / Longitude 2</field>
      <field type="float" name="p2z" units="m">z position 2 / Altitude 2</field>
    </message>
```

--------------------------------

### Set MAVLink Install Prefix for CMake

Source: https://mavlink.io/en/mavgen_c

Sets the CMake prefix path to locate the local MAVLink installation directory. This is necessary for the `find_package(MAVLink)` command to succeed.

```shell
cd ../my_program
cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=../mavlink/install
```

--------------------------------

### Initialize Signing Structure

Source: https://mavlink.io/en/mavgen_c/message_signing_c.html

Initialize the `mavlink_signing_t` structure with secret key, link ID, timestamp, flags, and an optional callback for accepting unsigned packets.

```c
mavlink_signing_t signing;
memset(&signing, 0, sizeof(signing));
memcpy(signing.secret_key, key.secret_key, 32);
signing.link_id = (uint8_t)chan;
signing.timestamp = key.timestamp;
signing.flags = MAVLINK_SIGNING_FLAG_SIGN_OUTGOING;
signing.accept_unsigned_callback = accept_unsigned_callback;

mavlink_status_t *status = mavlink_get_channel_status(chan);
status.signing = &signing;
```

--------------------------------

### Remove Existing MAVlink ROS Package

Source: https://mavlink.io/en/getting_started/ros.html

Before installing the MAVROS MAVlink library, remove any previously installed MAVlink ROS packages to avoid conflicts. This command is specific to your ROS distribution.

```shell
sudo apt-get remove ros-${rosversion -d}-mavlink
```

--------------------------------

### Camera Definition XML Example

Source: https://mavlink.io/en/services/camera_def.html

This XML file defines camera parameters, their types, default values, and relationships, including options, exclusions, and conditional ranges.

```xml
<?xml version="1.0" encoding="UTF-8" ?>
<mavlinkcamera>
    <definition version="7">
        <model>T100</model>
        <vendor>Foo Industries</vendor>
    </definition>
    <parameters>
        <!-- control = 0 tells us this should not create an automatic UI control -->
        <parameter name="CAM_MODE" type="uint32" default="1" control="0">
            <description>Camera Mode</description>
            <!-- This tells us when this parameter changes, these parameters must be updated (requested)-->
            <updates>
                <update>CAM_SHUTTERSPD</update>
                <update>CAM_ISO</update>
                <update>CAM_VIDRES</update>
            </updates>
            <options>
                <option name="Photo" value="0">
                    <!-- This tells us when Camera Mode is set to Photo mode, the following parameters should be ignored (hidden from UI or disabled)-->
                    <exclusions>
                        <exclude>CAM_VIDRES</exclude>
                        <exclude>CAM_VIDFMT</exclude>
                    </exclusions>
                </option>
                <option name="Video" value="1">
                    <!-- Conversely, when Camera Mode is set to Photo mode, the following parameters should be ignored (hidden from UI or disabled)-->
                    <exclusions>
                        <exclude>CAM_PHOTOFMT</exclude>
                        <exclude>CAM_PHOTOQUAL</exclude>
                        <exclude>CAM_COLORMODE</exclude>
                    </exclusions>
                    <parameterranges>
                        <parameterrange parameter="CAM_ISO" condition="CAM_EXPMODE=1">
                            <roption name="100" value="100" />
                            <roption name="150" value="150" />
                            <roption name="200" value="200" />
                            <roption name="300" value="300" />
                            <roption name="400" value="400" />
                            <roption name="600" value="600" />
                            <roption name="800" value="800" />
                            <roption name="1600" value="1600" />
                            <roption name="3200" value="3200" />
                        </parameterrange>
                    </parameterranges>
                </option>
            </options>
        </parameter>
        <parameter name="CAM_WBMODE" type="uint32" default="0">
            <description>White Balance Mode</description>
            <options>
                <option name="Auto" value="0" />
                <option name="Incandescent" value="1" />
                <option name="Sunset" value="3" />
                <option name="Sunny" value="4" />
                <option name="Cloudy" value="5" />
                <option name="Fluorescent" value="7" />
            </options>
        </parameter>
        <parameter name="CAM_EXPMODE" type="uint32" default="0">
            <description>Exposure Mode</description>
            <updates>
                <update>CAM_SHUTTERSPD</update>
                <update>CAM_ISO</update>
            </updates>
            <options default="0">
                <option name="Auto" value="0">
                    <exclusions>
                        <exclude>CAM_ISO</exclude>
                        <exclude>CAM_SHUTTERSPD</exclude>
                    </exclusions>
                </option>
                <option name="Manual" value="1">
                    <exclusions>
                        <exclude>CAM_EV</exclude>
                    </exclusions>
                </option>
            </options>
        </parameter>
        <parameter name="CAM_SHUTTERSPD" type="float" default="0.016666">
            <description>Shutter Speed</description>
            <options>
                <option name="4" value="4" />
                <option name="3" value="3" />
                <option name="2" value="2" />
                <option name="1" value="1" />
                <option name="1/30" value="0.033333" />
                <option name="1/60" value="0.016666" />
                <option name="1/125" value="0.008" />

```

--------------------------------

### MAV_CMD_STORM32_DO_GIMBAL_MANAGER_SETUP (60010)

Source: https://mavlink.io/en/messages/storm32.html

Command to configure a gimbal manager. Note: This is a Work In Progress command.

```APIDOC
## MAV_CMD_STORM32_DO_GIMBAL_MANAGER_SETUP (60010)

### Description
Command to configure a gimbal manager. The selected profile is reported in the STORM32_GIMBAL_MANAGER_STATUS message.

### Parameters
- **Param 1 (Profile)** (uint32) - Required - Gimbal manager profile (0 = default).
- **Param 7 (Gimbal ID)** (uint32) - Required - Gimbal ID of the gimbal manager to address.
```

--------------------------------

### Mavgen Command Line Tool Help

Source: https://mavlink.io/en/getting_started/generate_libraries.html

Displays the full syntax and available options for the mavgen.py command-line tool. This includes language, protocol version, and validation settings.

```sh
usage: mavgen.py [-h] [-o OUTPUT] [--lang {Ada,C,CS,JavaScript,JavaScript_Stable,JavaScript_NextGen,TypeScript,Python2,Python3,Python,Lua,WLua,ObjC,Swift,Java,C++11}]
                 [--wire-protocol {0.9,1.0,2.0}] [--no-validate] [--error-limit ERROR_LIMIT] [--strict-units]
                 XML [XML ...]

This tool generate implementations from MAVLink message definitions

positional arguments:
  XML                   MAVLink definitions

options:
  -h, --help            show this help message and exit
  -o OUTPUT, --output OUTPUT
                        output directory.
  --lang {Ada,C,CS,JavaScript,JavaScript_Stable,JavaScript_NextGen,TypeScript,Python2,Python3,Python,Lua,WLua,ObjC,Swift,Java,C++11}
                        language of generated code [default: Python]
  --wire-protocol {0.9,1.0,2.0}
                        MAVLink protocol version. [default: 1.0]
  --no-validate         Do not perform XML validation. Can speed up code generation if XML files are known to be correct.
  --error-limit ERROR_LIMIT
                        maximum number of validation errors to display
  --strict-units        Perform validation of units attributes.

```

--------------------------------

### Add MAVLink Library to CMake Project

Source: https://mavlink.io/en/mavgen_c/index.html

Install MAVLink headers locally using CMake and then find the package in your project's CMakeLists.txt. Pass the local install directory to CMake when building your program.

```sh
cmake -Bbuild -H. -DCMAKE_INSTALL_PREFIX=install -DMAVLINK_DIALECT=common -DMAVLINK_VERSION=2.0
cmake --build build --target install
```

```cmake
find_package(MAVLink REQUIRED)

add_executable(my_program my_program.c)

target_link_libraries(my_program PRIVATE MAVLink::mavlink)
```

```sh
cd ../my_program
cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=../mavlink/install
```

--------------------------------

### MAVLink Command Entry Example (XML)

Source: https://mavlink.io/en/guide/xml_schema.html

Defines a MAVLink command entry, specifying its value, name, and parameters. Use this structure to define custom commands or understand existing ones.

```xml
<enum name="MAV_CMD">
....
      <entry value="94" name="MAV_CMD_NAV_PAYLOAD_PLACE" hasLocation="true" isDestination="true">
        <description>Descend and place payload. Vehicle moves to specified location, descends until it detects a hanging payload has reached the ground, and then releases the payload. If ground is not detected before the reaching the maximum descent value (param1), the command will complete without releasing the payload.</description>
        <param index="1" label="Max Descent" units="m" minValue="0">Maximum distance to descend.</param>
        <param index="2">Empty</param>
        <param index="3">Empty</param>
        <param index="4">Empty</param>
        <param index="5" label="Latitude">Latitude</param>
        <param index="6" label="Longitude">Longitude</param>
        <param index="7" label="Altitude" units="m">Altitude</param>
      </entry>
...
</enum>
```

--------------------------------

### CreateDirectory

Source: https://mavlink.io/en/services/ftp.html

Sends a command to create a new directory at the specified path. The operation will fail if the directory is not empty.

```APIDOC
## CreateDirectory

### Description
Sends a command to create a directory at the specified path. The drone responds with an ACK on success or NAK on failure.

### Parameters
- **data[0]** (string) - Required - The full path of the directory to be created.
- **size** (integer) - Required - The length of the directory path string.
```

--------------------------------

### MAV_CMD_IMAGE_START_CAPTURE (2000)

Source: https://mavlink.io/en/messages/common.html

Initiates an image capture sequence on a target camera.

```APIDOC
## MAV_CMD_IMAGE_START_CAPTURE (2000)

### Description
Start image capture sequence. CAMERA_IMAGE_CAPTURED must be emitted after each capture.

### Parameters
- **Param 1 (Target Camera ID)** - Target camera ID. 7 to 255: MAVLink camera component id. 1 to 6 for cameras attached to the autopilot. 0: all cameras.
- **Param 2 (Interval)** - Desired elapsed time between two consecutive pictures (in seconds).
- **Param 3 (Total Images)** - Total number of images to capture. 0 to capture forever.
- **Param 4 (Sequence Number)** - Capture sequence number starting from 1. Only valid for single-capture.
```

--------------------------------

### MAV_CMD_DO_SET_MODE (176)

Source: https://mavlink.io/en/messages/common.html

Set system mode.

```APIDOC
## MAV_CMD_DO_SET_MODE (176)

### Description
Set system mode.

### Parameters
- **Param 1 (Mode)** (float) - Mode flags. MAV_MODE values can be used to set some mode flag combinations.
- **Param 2 (Custom Mode)** (float) - Custom system-specific mode.
- **Param 3 (Custom Submode)** (float) - Custom sub mode.
```

--------------------------------

### MAV_CMD_GIMBAL_REQUEST_AXIS_CALIBRATION (42503)

Source: https://mavlink.io/en/messages/ardupilotmega.html

Starts commutation calibration on the gimbal.

```APIDOC
## MAV_CMD_GIMBAL_REQUEST_AXIS_CALIBRATION (42503)

### Description
Starts commutation calibration on the gimbal.
```
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