Lua Script Reference

Lua General Functions general purpose functions
Lua Model Functions model manipulation functions
Lua Display Functions LCD display functions

General syntax

Local vs. global

All Lua scripts in OpenTX exist in same Lua environment. This means, that they share global functions and variables. Using global variable with the same name from two different scripts could lead to unpredictable results. Therefore the use of global variables and functions should be avoided!

TODO: how to share data between scripts

Warning

Even variables defined inside local functions without local keyword are global. For example if we have two scripts, script1:

local function run()
    global_var = 7
    local local_var = "foo"
end

and script2:

local function run()
    if global_var == 7 then
        print("Whoops")
    end
    if local_var == "foo" then
        print("We don't get here, local_var is nil")
    end
end

If we execute both scripts, we would see a printout "Whoops" (note: OpenTX currently does not support print function, this is just an example). This means that variable global_var is actually global even if it is first defined in some local function.

###Local variables Script can have any number of local variables, their value is preserved between each call to run function. They are defined as:

local simple_number = 4
local some_array = {1, 2, 120}

Local variables are only visible to the script that defined them. Two scripts can define a local variable with the same name. These two variables don't share anything, each script has his own instance of variable. In other words, scripts can't share local variables.

On the other hand variables local_var are separate for each script and don't share theri value (they only happen to have the same name).

Local functions

Script can have any number of local functions:

local function some_function(a, b, c)
    local value1 = a + b * c
    return value1
end

Inputs syntax

Input are only used in model scripts. However same number format is used when using function getValue().

Number format

Inputs are analogue values from opentTX that converted to 16 bit signed integers before they reach Lua script.

Analogue values such as sticks and sliders have value multiplied by 10. Examples:

aileron stick value	input value to script
0	0
60.5	650
-100.0	-1000

Switches (real and logical) are represented as:

switch position	input value to script
down	-1000
middle	0
up	1000

Telemetry values TODO

telemetry value	input value to script
altitude 120.5m	TODO
A1 voltage 5.47V	TODO
consumption 1260mAh	TODO

Types of inputs

There are two kinds of inputs:

SOURCE
VALUE

SOURCE

Source type provides current value of selected OpenTX variable (stick position, slider, channel). User assigns assigns actual source for this input in Custom script menu. Source can be any value OpenTX knows about (inputs, channels, telemetry values, switches, custom functions,...).

Syntax: { name, SOURCE }
Example: { "Aileron", SOURCE }

Defines SOURCE type input with name Aileron. Name length is limited to TODO.