- Wed Feb 25, 2015 10:59 am
#10699
I've eventually got MQTT to work on this build, but it's taken a long time! To figure out why it wasn't working I created a state machine so I could monitor each step. The main issue seemed to be the m:publish function which can't be recalled until it's completed its work. I've now trimmed it back and the code to the minimum that works for me. It seems to survive temporarily stopping the broker and the wifi node. "init.lua" contains just dofile("MQTT.lc") after compiling with node.compile("MQTT.lua"). Remaining HEAP is 11912 - so not much left to play with!
Code: Select all
--—————————————————————————–
--MQTT.lua test code for NODEMCU 0.9.5 build 20150213
--LICENCE: http://opensource.org/licenses/MIT
--Over engineered by: MikeV for an ESP01 module
--—————————————————————————–
--External modules
--—————————————————————————–
t=require("DS18B20") --see http://tech.scargill.net/lua-and-the-ds18b20ds18b20p-temperature-sensor/
--—————————————————————————–
--Configuration parameters & initialise variables
--—————————————————————————–
broker = "192.168.1.108" -- 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
GPIO0 = 3 -- IO Index of GPIO0 which is connected to a DS18B20
GPIO2 = 4 -- IO Index of GPIO2 which is connected to an LED
gpio.mode(GPIO2,gpio.OUTPUT) -- Make GPIO2 an output
count = 0 -- Test number of mqtt_do cycles
mqtt_state = 0 -- State control
--—————————————————————————–
function mqtt_do()
count = count + 1 -- For testing number of interations before failure
temp = t.readNumber(GPIO0) -- get reading from DS18B20
if mqtt_state < 5 then
mqtt_state = wifi.sta.status() --State: Waiting for wifi
elseif mqtt_state == 5 then
m = mqtt.Client(clientID, 120, userID, userPWD)
mqtt_state = 10 -- State: initialised but not connected
m:on("message",
function(conn, topic, data)
print(topic .. ":" ) --topic is not examined only printed for the purposes of this test
if data ~= nil then
print(data)
if data == "OFF" then -- Only "OFF" or "ON" is recognised to change GPIO2 state
gpio.write(GPIO2,gpio.LOW)
elseif data == "ON" then
gpio.write(GPIO2,gpio.HIGH)
end
end
end)
m:on("offline",
function(conn)
print("Offline!")
mqtt_state = 10 -- State: reset to initialised but not connected
end)
elseif mqtt_state == 10 then
m:connect( broker , mqttport, 0,
function(conn)
print("Connected to MQTT:" .. broker .. ":" .. mqttport .." as " .. clientID )
m:subscribe("sensor/"..clientID.."/action",0,
function(conn)
print("subscribed!")
mqtt_state = 20 -- Go to publish state
end)
end)
elseif mqtt_state == 20 then
mqtt_state = 25 -- Publishing...
if gpio.read(GPIO2) == 0 then -- Read the current state of GPIO2
io_status = "OFF"
else
io_status = "ON"
end
m:publish("sensor/"..clientID.."/temp", temp.."C GPIO:"..io_status.." #:"..count.." ", 0, 0,
function(conn)
-- Print confirmation of data published
print(temp.." degC GPIO:"..io_status.." #:"..count.." published!")
mqtt_state = 20 -- Finished publishing - go back to publish state.
end)
else print("Publishing..."..mqtt_state)
mqtt_state = mqtt_state - 1 -- takes us gradually back to publish state to retry
end
end
--—————————————————————————–
--Run it!
--—————————————————————————–
tmr.alarm(0, 1000, 1, function() mqtt_do() end)
which is necessary after the 20150127 firmware.
