ESP8266 Community Forum

- Tue Feb 09, 2016 7:54 am #40782 Hello!
Rookie Lua annd nodemcu user need some input on a few questions.

I am setting up some nodemcu units for my "smarthome".
I have read some code and tutorials around the Lua, and have a working mqtt connection that listens to a topic and reacts to the messages.
But i need my node to do several things, one of them is going to controll a steppermotor and a PIR sensor (and maybe a temperaturesensor).

Another node is going to have several buttons , some leds and maybe some encoders.

A third node is going to have temperaturesensor, relay and other komponents.

I have found som code on the forum to make MQTT work, but i am struggeling to expand the codes.
In my example i have found a code (Engeneerd by rutierut, inspired by MikeV) that controlls gpio output. Originaly it listens for the word "ON" and "OFF" on a spesific topic.
If i add an extra "else if input = <command>" i can listen for additional commands from the MQTT.

BUT, is it possible to load a file when a certain MQTT command is received? I want to start the stepper motor when i certain command is received, can i just put the stepper code in a single file and load it from "if input = <command> then <load file.lua>"?
How do i subscribe for additional topics?

How do i add additional buttons to the MQTT Button code in this discussion?
viewtopic.php?f=19&t=2029

Code: Select all-- Engeneerd by rutierut, inspired by MikeV

broker = "192.168.0.100"     -- IP or hostname of MQTT broker
mqttport = 1883          -- MQTT port (default 1883)
userID = ""              -- username for authentication if required
userPWD  = ""            -- user password if needed for security
clientID = "ESP1"        -- Device ID
GPIO2 = 4                -- IO Index of GPIO2 which is connected to a device

gpio.mode(GPIO2, gpio.OUTPUT)

-- Wifi credentials
wifi.setmode(wifi.STATION)
wifi.sta.config("Rosander","280411050313")

function wifi_connect()
   ip = wifi.sta.getip()
     if ip ~= nil then
          print('Connected, ip is:' .. ip)
          tmr.stop(1)
          ready = 1
     else
          ready = 0
     end
end

function mqtt_do()
if ready == 1 then
  m = mqtt.Client(clientID, 120, userID, userPWD)
  m:connect( broker , mqttport, 0,
  function(conn)
    print("Connected to MQTT:" .. broker .. ":" .. mqttport .." as " .. clientID )
    tmr.stop(0)
    connected = 1;
    sub_mqtt()
    m:on('message', function(conn, topic, input)
         print(input)
     if input == "ON" then
       gpio.write(GPIO2, gpio.HIGH)
      elseif input == "OFF" then
       gpio.write(GPIO2, gpio.LOW)
      elseif input == "TEST" then
       print('Dette var en test')
     else
       print('error')
     end
    end)
  end)
end
end


function sub_mqtt()
    m:subscribe('testtopic', 0, function(conn)
    print('Subscribed')
    end)
    end
   
     
tmr.alarm(0, 1000, 1, function()
     mqtt_do()
     tmr.delay(1000)
     end)
     
tmr.alarm(1, 1111, 1, function()
     wifi_connect()
     end)


- Wed Feb 10, 2016 9:11 am #40851 You can dofile , I not sure about not losing your global vars though....
Probably could use REQUIRE [ie] reacall function from flash / execute / set to nil
I just put 4 segments of my web page in flash the load/send using require--works good
frees up ram, but will run a little slower which caused serial RX issues for me Uart buffer over run.
I know no way to alter UART buffer size..

You will find that LUA Q&A is quite lacking from people in the know ... TerryE will sometimes respond ,when he has time, I think he's the only one. Thx Terry .

If you are planning to do a lot of stuff with a single ESP , you might want to consider
Arduino ESP .... Nodemcu runs short on memory very easily , just rearranging code
can affect free mem, and free memory is often fragmented.