Continuous throttle pitch for EdgeTX radios

thrvar.lua

-- thrvar.lua  —  Throttle → continuous pitch via PLAY_BACKGROUND
-- Place in /SCRIPTS/FUNCTIONS/thrvar.lua
-- Add to Special Functions: Switch=<your switch>, Function=Lua, File=thrvar

-- ── Config ────────────────────────────────────────────────────────────────
local MIN_FREQ  = 250    -- Hz when throttle is just above the floor
local MAX_FREQ  = 1000   -- Hz at full throttle
local THR_FLOOR = -950   -- throttle values at or below this = silence
                         -- (-1024 is absolute minimum; -950 leaves a small deadband)
-- ─────────────────────────────────────────────────────────────────────────

local thr_id

local function init()
  local info = getFieldInfo("thr")
  if info then thr_id = info.id end
end

local function silence()
  playTone(150, 1, 0, PLAY_BACKGROUND)
end

local function run()
  local thr = getValue(thr_id or "thr")  -- −1024 … +1024
  if thr <= THR_FLOOR then
    silence()
    return
  end
  local freq = MIN_FREQ + math.floor((thr - THR_FLOOR) * (MAX_FREQ - MIN_FREQ) / (1024 - THR_FLOOR))
  playTone(freq, 30000, 0, PLAY_BACKGROUND)
end

local function background()
  silence()
end

return { init = init, run = run, background = background }