rssiLEDs.lua

-- RSSI LED Ring script
-- Based on the throttle indicator on the LED bar by btastic_fpv
--
-- Ring 1 shows 1RSS, ring 2 shows 2RSS (ExpressLRS diversity).
-- If 2RSS is unavailable, ring 2 mirrors ring 1.
-- If a ring has no signal at all, its first LED pulses slowly.

---------------------------------------------------------------
-- User settings
---------------------------------------------------------------

-- Ring color (0-255 per channel). Change this line for other variants.
local COLOR = {255, 255, 255}   -- white
-- local COLOR = {0, 120, 255}  -- blue
-- local COLOR = {255, 40, 0}   -- orange

local RSSI_MIN = -117           -- dBm mapped to an empty ring
local RSSI_MAX = -3             -- dBm mapped to a full ring

local PULSE_PERIOD = 200        -- link-lost pulse period in 10 ms ticks (200 = 2 s)
local PULSE_MIN = 8             -- dimmest level of the pulse (0-255)

local LED_GROUP1 = {10,11,12,13,14,15,16,17,18,19}
local LED_GROUP2 = {0,1,2,3,4,5,6,7,8,9}

---------------------------------------------------------------
-- Helpers
---------------------------------------------------------------

local function init()
end

-- Set one LED to COLOR scaled by level (0-255)
local function setLed(index, level)
  local s = level / 255
  setRGBLedColor(index,
    math.floor(COLOR[1] * s + 0.5),
    math.floor(COLOR[2] * s + 0.5),
    math.floor(COLOR[3] * s + 0.5))
end

-- Smooth 0..1..0 pulse, returned as a brightness level (PULSE_MIN-255)
local function pulseLevel()
  local phase = (getTime() % PULSE_PERIOD) / PULSE_PERIOD
  local wave = (1 - math.cos(phase * 2 * math.pi)) / 2
  return math.floor(PULSE_MIN + wave * (255 - PULSE_MIN))
end

-- Convert dBm to 0.0-1.0, or nil if there is no signal
local function rssiToFraction(dbm)
  if dbm == nil or dbm == 0 then
    return nil
  end
  return math.max(0, math.min(1, (dbm - RSSI_MIN) / (RSSI_MAX - RSSI_MIN)))
end

-- Fill a ring. fraction is 0.0-1.0, or nil for the link-lost pulse.
local function fillSlots(fraction, ledGroup)
  local n = #ledGroup

  -- No signal: pulse the first LED, keep the rest off
  if fraction == nil then
    local level = pulseLevel()
    for i = 1, n do
      setLed(ledGroup[i], (i == 1) and level or 0)
    end
    return
  end

  local lit = fraction * n
  local full = math.floor(lit)
  -- Squared for a more even-looking fade on the partial LED
  local partial = math.floor(((lit - full) ^ 2) * 255)

  for i = 1, n do
    if i <= full then
      setLed(ledGroup[i], 255)
    elseif i == full + 1 then
      setLed(ledGroup[i], partial)
    else
      setLed(ledGroup[i], 0)
    end
  end
end

---------------------------------------------------------------
-- Main
---------------------------------------------------------------

local function run()
  local f1 = rssiToFraction(getValue("1RSS"))
  local f2 = rssiToFraction(getValue("2RSS"))

  fillSlots(f1, LED_GROUP1)
  fillSlots(f2 or f1, LED_GROUP2)   -- mirror ring 1 if 2RSS is unavailable

  applyRGBLedColors()
end

local function background()
end

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