Module Development

This section is a quick tutorial on how to create custom modules in MAVProxy.

Location

If developing from the MAVProxy source code, modules are placed in the MAVProxy/modules folder. Then the setup.py build install --user routine needs to be run in order to (re)install MAVProxy and the modules in this folder which will be automatically picked up and become part of the installation.

Note

MAVProxy modules will not be able to detect and run any modules not compiled as part of the above setup.py. This is because MAVProxy runs modules from the Python package install directory, not the MAVProxy source code directory.

The module can then be loaded then using the module load myModule in MAVProxy.

Module File Structure

At the base level, a MAVProxy module is an instance of the MPModule class, with hooks for initialisation and reading Mavlink packets:

#!/usr/bin/env python
'''module template'''
import time, math
from pymavlink import mavutil
from MAVProxy.modules.lib import mp_module
from MAVProxy.modules.lib.mp_settings import MPSetting

class TestModule(mp_module.MPModule):
  def __init__(self, mpstate):
    super(TestModule, self).__init__(mpstate, "test", "test module")
    '''initialisation code'''

  def mavlink_packet(self, m):
    '''handle a mavlink packet'''

def init(mpstate):
  '''initialise module'''
  return TestModule(mpstate)           ``

The initialisation section defines commands and module-wide variables. To add a command:

self.add_command('bat', self.cmd_bat, "show some information")

The above will add the “bat” command to MAVProxy, which the MAVProxy help will show “show some information” and the self.cmd\_bat function will be run.

Within the packet handling, the Mavlink reference is useful for filtering the incoming packets for the relevant data:

if m.get_type() == 'VFR_HUD':
  curspeed =  m.airspeed

The above example will set the variable curspeed to the current airspeed of the vehicle, whenever a VFR_HUD packet is received.

There are a great number of MAVProxy modules, so the best reference would be to look through the these modules for examples of what you want to do.

In particular, the example module (mavproxy_example.py) provides annotated code of many common tasks that can be performed with modules.