solartrack

-- ============================================================
-- SOLAR TRACKER
-- CC:Tweaked + Create Rotation Speed Controller
--
-- SAFE / CONSERVATIVE VERSION
--
-- IMPORTANT:
-- When this program starts, the panel MUST physically be
-- facing EAST.
--
-- Coordinate system:
--
--       EAST          SOUTH          WEST
--        -90°           0°           +90°
--
-- The computer does not read the Mechanical Bearing's actual
-- angle. It maintains an estimated position based on the
-- rotation commands it sends.
--
-- ============================================================


-- ============================================================
-- FIND ROTATION SPEED CONTROLLER
-- ============================================================

local rsc = peripheral.find("Create_RotationSpeedController")

if not rsc then
    error("ERROR: Create_RotationSpeedController not found.")
end


-- ============================================================
-- CONFIGURATION
-- ============================================================

-- Absolute software limits.
local MIN_ANGLE = -90
local MAX_ANGLE = 90

-- Known physical starting position.
local START_ANGLE = -90

-- Park position for nighttime.
local PARK_ANGLE = -90


-- ------------------------------------------------------------
-- SAFETY RPM
-- ------------------------------------------------------------
--
-- DO NOT use 32 RPM for normal tracking.
--
-- The panel only needs roughly 0.5 RPM to follow the
-- Minecraft sun continuously.
--
-- We use a low maximum speed so the mechanism cannot suddenly
-- receive a huge command when there is a position error.
--

local MAX_TRACKING_RPM = 2

-- Maximum speed allowed while returning to East.
local MAX_PARK_RPM = 1


-- ------------------------------------------------------------
-- CONTROL
-- ------------------------------------------------------------

local KP = 0.35

-- Ignore tiny errors.
local DEADZONE = 1.0


-- ------------------------------------------------------------
-- GEAR RATIO
-- ------------------------------------------------------------
--
-- Keep this at 1.0 unless your gearing changes.
--
-- With the way the position calculation below is written:
--
-- panel RPM = motor RPM * GEAR_RATIO
--

local GEAR_RATIO = 1.0


-- ------------------------------------------------------------
-- LOOP TIMING
-- ------------------------------------------------------------
--
-- 0.1 seconds gives frequent updates but can cause lots of
-- target-speed changes.
--
-- 0.25 seconds is deliberately calmer.
--

local LOOP_TIME = 0.25


-- ------------------------------------------------------------
-- DIRECTION CHANGE PROTECTION
-- ------------------------------------------------------------
--
-- Don't immediately slam from positive RPM to negative RPM.
--
-- First command 0 RPM, wait, then reverse.
--

local DIRECTION_CHANGE_DELAY = 0.5


-- ============================================================
-- PANEL POSITION
-- ============================================================
--
-- This is intentionally NOT loaded from a file.
--
-- The physical assumption is:
--
--     PROGRAM START = PANEL FACING EAST
--
-- Therefore:
--

local panelAngle = START_ANGLE


-- ============================================================
-- MOTOR STATE
-- ============================================================

local currentRPM = 0


-- ============================================================
-- SAFE MOTOR CONTROL
-- ============================================================

local function stopMotor()

    if currentRPM ~= 0 then
        rsc.setTargetSpeed(0)
        currentRPM = 0
    end

end


local function setMotor(targetRPM, maximumRPM)

    maximumRPM = maximumRPM or MAX_TRACKING_RPM


    -- --------------------------------------------------------
    -- Round to Create's integer RPM requirement.
    -- --------------------------------------------------------

    targetRPM = math.floor(targetRPM + 0.5)


    -- --------------------------------------------------------
    -- Clamp RPM.
    -- --------------------------------------------------------

    if targetRPM > maximumRPM then
        targetRPM = maximumRPM
    elseif targetRPM < -maximumRPM then
        targetRPM = -maximumRPM
    end


    -- --------------------------------------------------------
    -- If we're already at the requested speed, do nothing.
    -- --------------------------------------------------------

    if targetRPM == currentRPM then
        return currentRPM
    end


    -- --------------------------------------------------------
    -- Direction change protection.
    -- --------------------------------------------------------

    if currentRPM ~= 0
        and targetRPM ~= 0
        and ((currentRPM > 0 and targetRPM < 0)
        or (currentRPM < 0 and targetRPM > 0)) then

        -- Stop first.
        rsc.setTargetSpeed(0)
        currentRPM = 0

        sleep(DIRECTION_CHANGE_DELAY)

    end


    rsc.setTargetSpeed(targetRPM)

    currentRPM = targetRPM

    return currentRPM

end


-- ============================================================
-- SUN POSITION
-- ============================================================

local function getSunAngle()

    local hour = os.time("ingame")

    -- 06:00 -> -90° East
    -- 12:00 ->   0° South
    -- 18:00 -> +90° West

    local angle = (hour - 12) * 15


    -- --------------------------------------------------------
    -- Clamp to physical panel limits.
    -- --------------------------------------------------------

    if angle < MIN_ANGLE then
        angle = MIN_ANGLE
    elseif angle > MAX_ANGLE then
        angle = MAX_ANGLE
    end


    return angle

end


-- ============================================================
-- DAY/NIGHT
-- ============================================================

local function isDaytime()

    local hour = os.time("ingame")

    return hour >= 6 and hour < 18

end


-- ============================================================
-- SAFE POSITION UPDATE
-- ============================================================

local function updatePanelPosition(rpm, seconds)

    -- RPM -> degrees/second
    --
    -- 1 RPM = 6 degrees/second
    --

    local deltaAngle =
        rpm * 6 * seconds * GEAR_RATIO


    panelAngle = panelAngle + deltaAngle


    -- --------------------------------------------------------
    -- HARD SOFTWARE LIMITS
    -- --------------------------------------------------------

    if panelAngle >= MAX_ANGLE then

        panelAngle = MAX_ANGLE
        stopMotor()

    elseif panelAngle <= MIN_ANGLE then

        panelAngle = MIN_ANGLE
        stopMotor()

    end

end


-- ============================================================
-- PARK PANEL AT EAST
-- ============================================================

local function parkPanel()

    local error = PARK_ANGLE - panelAngle


    -- --------------------------------------------------------
    -- Already parked.
    -- --------------------------------------------------------

    if math.abs(error) <= DEADZONE then

        panelAngle = PARK_ANGLE

        stopMotor()

        return true

    end


    -- --------------------------------------------------------
    -- Conservative proportional parking.
    -- --------------------------------------------------------

    local rpm = error * KP


    -- NEVER exceed park RPM.
    if rpm > MAX_PARK_RPM then
        rpm = MAX_PARK_RPM
    elseif rpm < -MAX_PARK_RPM then
        rpm = -MAX_PARK_RPM
    end


    rpm = setMotor(rpm, MAX_PARK_RPM)


    -- --------------------------------------------------------
    -- Update estimated position.
    -- --------------------------------------------------------

    updatePanelPosition(rpm, LOOP_TIME)


    return false

end


-- ============================================================
-- TRACK SUN
-- ============================================================

local function trackSun()

    local sunAngle = getSunAngle()

    local error = sunAngle - panelAngle


    -- --------------------------------------------------------
    -- Deadzone.
    -- --------------------------------------------------------

    if math.abs(error) <= DEADZONE then

        stopMotor()

        return sunAngle, error, 0

    end


    -- --------------------------------------------------------
    -- Proportional controller.
    -- --------------------------------------------------------

    local rpm = error * KP


    -- --------------------------------------------------------
    -- SAFETY LIMIT.
    -- --------------------------------------------------------

    if rpm > MAX_TRACKING_RPM then
        rpm = MAX_TRACKING_RPM
    elseif rpm < -MAX_TRACKING_RPM then
        rpm = -MAX_TRACKING_RPM
    end


    rpm = setMotor(rpm, MAX_TRACKING_RPM)


    -- --------------------------------------------------------
    -- Update our estimated position.
    -- --------------------------------------------------------

    updatePanelPosition(rpm, LOOP_TIME)


    return sunAngle, error, rpm

end


-- ============================================================
-- DISPLAY
-- ============================================================

local function display(day, sunAngle, error)

    term.clear()
    term.setCursorPos(1, 1)

    print("================================")
    print("       SAFE SOLAR TRACKER")
    print("================================")
    print("")

    print(string.format(
        "Minecraft Time : %05.2f",
        os.time("ingame")
    ))

    print(string.format(
        "Panel Angle    : %7.2f deg",
        panelAngle
    ))

    print(string.format(
        "Motor RPM      : %7d",
        currentRPM
    ))

    print("")

    if day then

        print(string.format(
            "Sun Angle      : %7.2f deg",
            sunAngle
        ))

        print(string.format(
            "Tracking Error : %7.2f deg",
            error
        ))

        print("")

        if math.abs(error) <= DEADZONE then

            print("STATUS: ALIGNED")

        elseif error > 0 then

            print("STATUS: ROTATING WEST")

        else

            print("STATUS: ROTATING EAST")

        end

    else

        print(string.format(
            "Park Position  : %7.2f deg",
            PARK_ANGLE
        ))

        print("")

        if math.abs(PARK_ANGLE - panelAngle) <= DEADZONE then

            print("STATUS: PARKED EAST")

        else

            print("STATUS: RETURNING EAST")

        end

    end

end


-- ============================================================
-- STARTUP
-- ============================================================

stopMotor()

panelAngle = START_ANGLE

term.clear()
term.setCursorPos(1, 1)

print("================================")
print("       SAFE SOLAR TRACKER")
print("================================")
print("")
print("STARTING...")
print("")
print("Assumed panel position:")
print("EAST (-90 degrees)")
print("")
print("Maximum tracking RPM:", MAX_TRACKING_RPM)
print("Maximum park RPM:", MAX_PARK_RPM)
print("")
print("Starting in 2 seconds...")

sleep(2)


-- ============================================================
-- MAIN LOOP
-- ============================================================

while true do

    local day = isDaytime()


    -- ========================================================
    -- DAY
    -- ========================================================

    if day then

        local sunAngle, error, rpm =
            trackSun()

        display(
            true,
            sunAngle,
            error
        )


    -- ========================================================
    -- NIGHT
    -- ========================================================

    else

        local parked = parkPanel()

        local error =
            PARK_ANGLE - panelAngle

        display(
            false,
            PARK_ANGLE,
            error
        )

    end


    sleep(LOOP_TIME)

end