Sending data from DHT22 temperature/humidity sensor and LDR luminosity sensor to ThingSpeak using Adafruit HUZZAH ESP8266 Breakout (NodeMCU 0.9.6). Wiring: http://imgur.com/eGqkAUY

dht_ldr.lua

my_thingspeak = {
  api_key = ""; -- your ThingSpeak channel write API key
}

pin = 4 -- GPIO2
temp, humi, lumi = 0, 0, 0
url = "/update?"

maj_v, min_v, dev_v = node.info()
user_agent = "NodeMCU "..maj_v.."."..min_v.."."..dev_v.." (ESP8266 Lua)" 

function send()
  dht_status, temp, humi = dht.read(pin)
  
  if dht_status == dht.OK then
    print("Temperature: "..temp.." C")
    print("Humidity:    "..humi.." %")
    url = url.."field1="..temp.."&field2="..humi.."&"
  elseif dht_status == dht.ERROR_CHECKSUM then
    print("DHT checksum error.")
  elseif dht_status == dht.ERROR_TIMEOUT then
    print("DHT time out.")
  end
  
  lumi = adc.read(0)
  print("Luminosity:  "..lumi)
  url = url.."field3="..lumi
    
  conn = net.createConnection(net.TCP, 0) 
  conn:connect(80, "184.106.153.149")
  
  conn:on("receive", function(conn, payload)
    print(payload)
  end)
  
  conn:on("connection", function(conn)
    print("Sending data to ThingSpeak...")
    conn:send("GET "..url.." HTTP/1.1\r\n") 
    conn:send("Host: api.thingspeak.com\r\n") 
    conn:send("X-THINGSPEAKAPIKEY: "..my_thingspeak.api_key.."\r\n")
    conn:send("Accept: */*\r\n") 
    conn:send("User-Agent: "..user_agent.."\r\n")
    conn:send("\r\n")
  end)
  
  conn:on("sent", function(conn)
    print("Done.")
    conn:close()
  end)
end

send()

tmr.alarm(0, 60000, 1, function()
  send()
end)

init.lua

my_network = {
  essid = "";    -- your ESSID name
  password = ""; -- your ESSID password
}

print("Setting up WiFi...")
wifi.setmode(wifi.STATION)
wifi.sta.config(my_network.essid, my_network.password)
wifi.sta.connect()

tmr.alarm(0, 1000, 1, function()
  sta_status = wifi.sta.status()
  
  if sta_status == 1 then     --1: STATION_CONNECTING
    print("Connecting...")
  elseif sta_status == 5 then --5: STATION_GOT_IP
    tmr.stop(0)
    print("Done.")
    dofile("dht_ldr.lua")
  end 
end)