Niston Cloud's IoT Signaleer - Firmware 1.0

-- WiFi IoT Signaleer 1.0 for ESP8266/nodeMCU - See http://imgur.com/sNi8Ou6
-- (c) 2016 Chris Burri @ NISTON Engineering Works
-- http://niston.wordpress.com

-- HTTP Polling Version:
-- Periodically retrieves a status URL and updates connected lamps & beeper accordingly.
-- Status page must serve string in the format: "ID=SIGNLR;R=0;Y=0;G=1;S=0" where
-- R=Red Lamp, Y=Yellow Lamp, G=Green Lamp, S=Beeper and
-- 0=Off, 1=On, 2=Blink, 3=Blink_Reversed (see Signal definitions below for explanation of "reversed")
-- ID=SIGNLR is the Protocol's Magic String. It must preclude everything else and match with what's in the magicID variable.


-- Signaleer configuration
httpURL = "https://my.server.com/signaleer.aspx";   -- status page URL
wlanSSID = "wlanSSID";      -- WiFi network name
wlanPwd = "wlanPassword";   -- WiFi network password
pollInterval = 90;          -- HTTP polling run interval (polling for status update) in seconds
pollMaxRetries = 5;         -- maximum http.get() retries during poll run before aborting
pollRetryDelay = 5;         -- delay in seconds between failure and rescheduled poll
beepMaxDuration = 15;       -- maximum audible alert duration in seconds

-- Code Below --

-- Update protocol related
magicID = "ID=SIGNLR";      -- magic string

-- Timer definitions (7 IDs available form 0...6).
timerBlink = 0;             -- Main/Blinker procedure timer
timerPoll = 1;              -- HTTP poll procedure timer
timerRescheduler = 2;       -- HTTP failed poll reschedule timer
timerResetBeeper = 3;       -- Beep limiter timer

-- GPIO pin definitions
pinBeeper = 1;              -- beeper GPIO pin
pinLampRed = 2;             -- red lamp GPIO pin
pinLampYellow = 6;          -- yellow lamp GPIO pin
pinLampGreen = 7;           -- green lamp GPIO pin

-- Signal definitions
SIG_OFF = "0";              -- signal off
SIG_ON = "1";               -- signal on
SIG_BLINK = "2";            -- signal alternating (2Hz)
SIG_BLINK_REV = "3";        -- signal alternating (2Hz reversed: on when blink is off, off when blink is on)

-- signal image variables
signalRed = SIG_OFF;        -- red signal lamp
signalYellow = SIG_OFF;     -- yellow signal lamp
signalGreen = SIG_OFF;      -- green signal lamp
signalBeeper = SIG_OFF;     -- piezo beeper

-- State variables
intervalBlink = 500;        -- milliseconds between run/blinker state change intervals - do NOT configure this
stringLastStatus = nil;     -- last obtained status string; nil when no update
blinkState = 0;             -- blinker status; alternates between 0 and 1 at 2Hz (intervalBlink=500ms)
pollFails = 0;              -- count of subsequently failed HTTP polls. reset to zero after pollMaxRetries
flagBeeptimeExceeded = 0;   -- Beep duration limiter: set to 1 if beeper is to be silenced
signalBeeperPrevious = 0;   -- previous beeper state, used to detect state transitions

-- Initialize GPIO ports
function InitGPIO()
    gpio.mode(pinBeeper,gpio.OUTPUT);
    gpio.mode(pinLampRed,gpio.OUTPUT);
    gpio.mode(pinLampYellow, gpio.OUTPUT);
    gpio.mode(pinLampGreen, gpio.OUTPUT);
    gpio.write(pinBeeper, 0);
    gpio.write(pinLampRed, 0);
    gpio.write(pinLampYellow, 0);
    gpio.write(pinLampGreen, 0);
end

-- WiFi STA_GOTIP callback
function WifiConnected(previousState)
  ip, nm, gw = wifi.sta.getip();
  print("WiFi connected (DHCP). IPAddr=" .. ip .. " Netmask=" .. nm .. " Gateway=" .. gw);
  ExecutePoll(); -- poll immediately when connected
end

-- Wifi STA_WRONGPWD callback
function WifiWrongPwd()
  print("WiFi connection failed: Invalid Password.");
end

-- Wifi STA_CONNECTING callback
function WifiConnecting()
  ssid, password, bssid_set, bssid = wifi.sta.getconfig();
  print("WiFi connecting to " .. ssid .. " (" .. bssid .. ")...");
end

-- Wifi STA_FAIL callback
function WifiConnectionFail()
 print("WiFi connection failed: Connection Failure.");
end

-- WiFi Setup
function SetupWiFi()
  wifi.sta.eventMonStop();
  wifi.sta.autoconnect(0);
  wifi.setmode(wifi.STATION);
  wifi.setphymode(wifi.PHYMODE_N);
  wifi.sta.sethostname("Signaleer");
  wifi.sta.config(wlanSSID, wlanPwd, 0);
  wifi.sleeptype(wifi.NONE_SLEEP);
  wifi.sta.eventMonReg(wifi.STA_GOTIP, function(previous_State) WifiConnected(previous_State) end);
  wifi.sta.eventMonReg(wifi.STA_WRONGPWD, function() WifiWrongPwd() end);
  wifi.sta.eventMonReg(wifi.STA_CONNECTING, function() WifiConnecting() end);
  wifi.sta.eventMonReg(wifi.STA_FAIL, function() WifiConnectionFail() end);
  wifi.sta.eventMonStart(200);
  wifi.sta.connect();
  wifi.sta.autoconnect(1);
end

-- test all actors (lamp & beeper test)
function TestActors()
 ClearActors();
 Beep(500);
 tmr.delay(1000000);
 tmr.wdclr();
 gpio.write(pinLampRed, 1);
 Beep(75);
 tmr.delay(1000000);
 tmr.wdclr();
 gpio.write(pinLampYellow, 1);
 Beep(75);
 tmr.delay(1000000);
 tmr.wdclr();
 gpio.write(pinLampGreen, 1);
 Beep(75);
 tmr.delay(1000000);
 tmr.wdclr();
 ClearActors();
 tmr.delay(1000000);
 tmr.wdclr();
end

-- stop all actors
function ClearActors()
  gpio.write(pinBeeper, 0);
  gpio.write(pinLampRed, 0);
  gpio.write(pinLampYellow, 0);
  gpio.write(pinLampGreen, 0);
end

-- hard beep for duration milliseconds
function Beep(duration)
  duration = duration or 500;
  gpio.write(pinBeeper, 1);
  tmr.delay(duration * 1000);
  gpio.write(pinBeeper, 0);
end

-- signal image "WAITING FOR IP": red/yellow alternating blink
function SignalWaitIP()
    signalRed = SIG_BLINK;
    signalYellow = SIG_BLINK_REV;
    signalGreen = SIG_OFF;
    signalBeeper = SIG_OFF;
    UpdateSignaleer();
end

-- signal image "WAITING FOR UPDATE": red/yellow+green alternating blink
function SignalWaitUpdate()
    signalRed = SIG_BLINK;
    signalYellow = SIG_BLINK_REV;
    signalGreen = SIG_BLINK_REV;
    signalBeeper = SIG_OFF;
    UpdateSignaleer();
end

-- signal image "GENERAL ERROR": red/beeper alternating blink
function SignalErrorStatus()
    signalRed = SIG_BLINK;
    signalYellow = SIG_OFF;
    signalGreen = SIG_OFF;
    signalBeeper = SIG_BLINK_REV;
    UpdateSignaleer();
end

-- fetch status URL from HTTP server
function ExecutePoll()
  print("Polling " .. httpURL .. " for update...");
  http.get(httpURL, nil, function(code, data)
    if (code == 200) then
      -- reset poll fail count
      pollFails = 0;
      -- parse the received data
      if ParseStatusString(data) == 0 then
        print("OK: " .. stringLastStatus);
      else
        print("FAIL: Protocol error (Magic not found).");
      end
    else
      pollFails = pollFails + 1;
      if pollFails < pollMaxRetries then
        -- schedule retry
        print("FAIL (Code " .. code .. "): Scheduling retry #" .. pollFails .. "...");
        tmr.alarm(timerRescheduler, (pollRetryDelay * 1000), tmr.ALARM_SINGLE, function()
            -- execute rescheduled Poll
            ExecutePoll();
        end)
      else
        -- give up
        print("FAIL (Code " .. code .. "): Update failed.");
        stringLastStatus = 'ERROR';
        pollFails = 0;
      end
    end
  end)
end

-- parse status string from HTTP server
function ParseStatusString(statusString)
    -- statusString must start with protocol magic string
    if string.find(statusString, magicID) == 1 then
        -- parse status String (thanks to RyanE@Freenode)
        for kv in (statusString .. ";"):gfind("(.-);") do local _,_,k,v = kv:find("(.+)=(.+)")
            if (k == "R") then signalRed = v end
            if (k == "Y") then signalYellow = v end
            if (k == "G") then signalGreen = v end
            if (k == "S") then signalBeeper = v end
        end
        stringLastStatus = statusString;
        return 0;
    else
        -- magic ID not present : Communications error, probably wrong protocol/URL
        stringLastStatus = "ERROR";
        return -1;
    end
end

-- update signaleer with current signal image & implement beep duration limiter
function UpdateSignaleer()
    -- upate lamps
    UpdatePin(pinLampRed, signalRed);
    UpdatePin(pinLampYellow, signalYellow);
    UpdatePin(pinLampGreen, signalGreen);
    -- detect state transition: beeper disabled->enabled - arm beep limiter
    if signalBeeperPrevious == SIG_OFF and signalBeeper ~= SIG_OFF then
        -- spin up one-shot timer
        tmr.alarm(timerResetBeeper, (beepMaxDuration * 1000), tmr.ALARM_SINGLE, function()
            -- trigger beep limiter: set flag after beepMaxDuration
            flagBeeptimeExceeded = 1;
            --print("Beeper maximum alert duration exceeded; limiter triggered.");
        end)
    end
    -- detect state transition: beeper enabled->disabled - reset beep limiter
    if signalBeeperPrevious ~= SIG_OFF and signalBeeper == SIG_OFF then
        -- reset & disarm beep limiter
        flagBeeptimeExceeded = 0;
        tmr.stop(timerResetBeeper);
        tmr.unregister(timerResetBeeper);
    end
    signalBeeperPrevious = signalBeeper;
    -- check if beep time exceeded
    if flagBeeptimeExceeded == 0 then
        -- no, update beeper according to status string
        UpdatePin(pinBeeper, signalBeeper);
    else
        -- yes, always silence beeper
        UpdatePin(pinBeeper, SIG_OFF);
    end
end

-- update GPIO pin with signal value
function UpdatePin(pinNumber, Value)
    if Value == SIG_OFF then
      gpio.write(pinNumber, 0);
    elseif Value == SIG_ON then
      gpio.write(pinNumber, 1);
    elseif Value == SIG_BLINK then
      gpio.write(pinNumber, blinkState);
    elseif Value == SIG_BLINK_REV then
      gpio.write(pinNumber, 1 - blinkState);
    end
end

-- string splitter function [sourced from stackoverflow]
function SplitString(pString, pPattern)
   local Table = {}  -- NOTE: use {n = 0} in Lua-5.0
   local fpat = "(.-)" .. pPattern
   local last_end = 1
   local s, e, cap = pString:find(fpat, 1)
   while s do
      if s ~= 1 or cap ~= "" then
     table.insert(Table,cap)
      end
      last_end = e+1
      s, e, cap = pString:find(fpat, last_end)
   end
   if last_end <= #pString then
      cap = pString:sub(last_end)
      table.insert(Table, cap)
   end
   return Table
end

-- main program
print("");
print("");
print("WiFi IoT Signaleer - (c) 2016 Chris Burri @ NISTON Engineering Works");
print("See http://niston.wordpress.com");
print("");
-- initialize GPIO
InitGPIO();
-- Power On Self Test
print ("Lamps & Beeper Test...");
TestActors();
-- Setup and connect WiFi
SetupWiFi();

-- setup main "loop" timer
tmr.alarm(timerBlink, intervalBlink, 1, function()
  -- toggle blinker state
  blinkState = 1 - blinkState;
  -- update light signal & beeper status
  if wifi.sta.getip() == nil then
    -- waiting for IP: blink red/yellow alternating
    SignalWaitIP();
  elseif stringLastStatus == nil then
    -- first status update: blink red/yellow&green alternating
    SignalWaitUpdate();
  elseif stringLastStatus == 'ERROR' then
    -- ERROR: blink red
    SignalErrorStatus();
  else
    -- OK; Update signaleer according to signal image variables
    UpdateSignaleer();
  end
end)

-- setup HTTP polling timer
tmr.alarm(timerPoll, pollInterval * 1000, 1, function()
  if wifi.sta.getip() ~= nil then
    ExecutePoll();
  end
end)

-- ## END OF CODE ##