How to control LEDs

kwasi · January 24, 2021, 12:10am

I am trying to control an custom external LED board with the pixhawk in auto mode. the challenge is that every LED color (R,G,B) has a signal wire connected an auxiliary pin on the pixhawk and in auto mode, the pixhawk can output a desired PWM to one channel using the DO_SET_SERVO command. I want to output different PWM values at a time to different channels for a single DO_SET_SERVO command

iampete · January 24, 2021, 12:23am

Use scripting, it supports ProfiLEDs and NeoPixels.

kwasi · January 24, 2021, 2:22am

@iampete How do I use lua scripts when I am running in auto mode??

Notorious7 · January 25, 2021, 3:55pm

Lua scripts run independently in a separate thread when your FC boots up, to take control of what your lua script suppose to do after bootup you can time the events upon any conditions you like or can use RC switches to take control of events

kwasi · January 25, 2021, 4:47pm

@Notorious7 and @iampete. So haven’t fully explained what I am doing . I am controlling a swarm of light show drones and with the current capability of the pixhawk, only one servo channel can be controlled in an instance with DO_SET_SERVO command( that an control one LED color). What I want is to control 3 servo channels in an instance (to enable mixing of colors on the LED) else I will be stuck with only RGB for colors. The LED is made from custom PCB and is powered differently from the pixhawk. It only takes signal(PWM) from the pixhawk. Now with using LUA scripts, I would have to write a new script for individual drones which is not scalable

iampete · January 25, 2021, 4:56pm

you can read the mission commands with scripting, or a file on the SD card

kwasi · January 25, 2021, 5:38pm

@iampete Can you please point me to examples like that? Because I am auto-generating the waypoint mission file from a python script and I am still seeing that the mission will be executing one waypoint to another, only one entry for a mission command is made available: reference from https://mavlink.io/en/file_formats/

Notorious7 · January 25, 2021, 5:45pm

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/mission-load.lua

-- Example of loading a mission from the SD card using Scripting
-- Would be trivial to select a mission based on scripting params or RC switch

local function read_mission(file_name)

  -- Open file
  file = assert(io.open(file_name), 'Could open :' .. file_name)

  -- check header
  assert(string.find(file:read('l'),'QGC WPL 110') == 1, file_name .. ': incorrect format')

  -- clear any existing mission
  assert(mission:clear(), 'Could not clear current mission')

  -- read each line and write to mission
  local item = mavlink_mission_item_int_t()
  local index = 0
  while true do

    local data = {}

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github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/logging.lua

-- example of logging to a file on the SD card and to data flash
local file_name = "AHRS_DATA.csv"
local file

-- index for the data and table
local roll = 1
local pitch = 2
local yaw = 3
local interesting_data = {}

local function write_to_file()

  if not file then
    error("Could not open file")
  end

  -- write data
  -- separate with comas and add a carriage return
  file:write(tostring(millis()) .. ", " .. table.concat(interesting_data,", ") .. "\n")

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Check these out for how to read and write files from SD card

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/rgb_led_test.lua

-- This script is a test of led override

local count = 0

function update() -- this is the loop which periodically runs

  count = count + 1

  if count == 1 then
    -- solid red
    -- red,green,blue,rate hz, duration ms
    notify:handle_rgb(255,0,0,0)
  elseif count == 2 then
    -- solid green
    notify:handle_rgb(0,255,0,0)
  elseif count == 3 then
    -- solid blue
    notify:handle_rgb(0,0,255,0)
  elseif count == 4 then
    -- 1hz red  + green

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And this for changing colors of RGB leds

kwasi · January 25, 2021, 5:53pm

@Notorious7 I am going to work on that

kwasi · January 26, 2021, 1:10am

@Notorious7 one last ask, I am looking for line of lua script that will read the current mission index and print out all the parameters

james_pattison · January 26, 2021, 2:23am

https://github.com/ArduPilot/ardupilot/blob/ebfe593e38acefcc6d7d377f93e5d0cb9b9f81bc/libraries/AP_Scripting/examples/Mission_test.lua#L18 and https://github.com/ArduPilot/ardupilot/blob/ebfe593e38acefcc6d7d377f93e5d0cb9b9f81bc/libraries/AP_Scripting/examples/Mission_test.lua#L26