Simple wifi web server - hygrometer with DHT22 sensor

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Re: Simple wifi web server - hygrometer with DHT22 sensor

By kartman
- Tue Jan 27, 2015 10:37 pm #8377 I made a proper power supply for the esp board. It now seems to be much more stable. I should slap myself - I should've known better. As for the speed,it seems to be due to my tplink wireless adsl router. If I connect to my other router running openwrt, the performance is much better - not quite as snappy as I'd like, but adequate.
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Re: Simple wifi web server - hygrometer with DHT22 sensor

By jankop
- Fri Jan 30, 2015 8:53 am #8515 Previous program does not work correctly in floating point. That's why I edited it for floating point arithmetic. For proper operation, it is necessary to set in program fpmdht.lua sensor type. This is parameter typeSensor = "dht11" or "dht22".

Load program fpmdht.lua and dht.lua to ESP8266 with LuaLoader


Code: Select all--    Demo http server for sensors DHT11/22
--    Tested with Lua NodeMCU 0.9.5 build 20150127 floating point !!!
-- 1. Flash Lua NodeMCU to ESP module.
-- 2. Set in program fpmdht.lua sensor type. This is parameter typeSensor="dht11" or "dht22".
-- 3. You can rename the program fpmdht.lua to init.lua
-- 4. Load program fpmdht.lua and dht.lua to ESP8266 with LuaLoader
-- 5. HW reset module
-- 6. Login module to your AP - wifi.setmode(wifi.STATION),wifi.sta.config("yourSSID","yourPASSWORD")
-- 7. Run program fpmdht.lua - dofile(fpmdht.lua)
-- 8. Test IP address - wifi.sta.getip()
-- 9. Test it with your browser and true IP address of module.
--10. The sensor is repeatedly read every minute.
--11. The pictures on page are external.
--12. The length of html code is limited to 1460 characters including header.
--    The author of the program module dht.lua for reading DHT sensor is Javier Yanez
               --*******************************
sensorType="dht22"    -- set sensor type dht11 or dht22
               --*******************************

   wifi.setmode(wifi.STATION)
   --wifi.sta.config("yourSSID","yourPASSWORD")
   wifi.sta.connect()
   tmr.delay(1000000)
   humi="XX"
   temp="XX"
   fare="XX"
   count=1
   PIN = 4 --  data pin, GPIO2
--load DHT module and read sensor
function ReadDHT()
   dht=require("dht")
   dht.read(PIN)
   if sensorType=="dht11"then
   humi=dht.getHumidity()/256
   temp=dht.getTemperature()/256
   else
   humi=dht.getHumidity()/10
   temp=dht.getTemperature()/10
   end
   fare=(temp*9/5+32)
   print("Humidity:    "..humi.."%")
   print("Temperature: "..temp.." deg C")
   print("Temperature: "..fare.." deg F")
   -- release module
   dht=nil
   package.loaded["dht"]=nil
end

ReadDHT()
tmr.alarm(1,60000,1,function()ReadDHT()count=count+1 if count==5 then count=0 wifi.sta.connect()print("Reconnect")end end)

srv=net.createServer(net.TCP) srv:listen(80,function(conn)
    conn:on("receive",function(conn,payload)
   --print(payload) -- for debugging only
   strstr={string.find(payload,"GET / HTTP/1.1")}
   if(strstr[1]~=nil)then
   --generates HTML web site
   conn:send('HTTP/1.1 200 OK\r\nConnection: keep-alive\r\nCache-Control: private, no-store\r\n\r\n\
   <!DOCTYPE HTML>\
    <html><head><meta content="text/html;charset=utf-8"><title>ESP8266</title></head>\
   <body bgcolor="#ffe4c4"><h2>Hygrometer with<br>'..sensorType..' sensor</h2>\
   <h3><font color="green">\
   <IMG SRC="http://esp8266.fancon.cz/common/hyg.gif"WIDTH="64"HEIGHT="64"><br>\
   <input style="text-align: center"type="text"size=4 name="j"value="'..humi..'"> % of relative humidity<br><br>\
   <IMG SRC="http://esp8266.fancon.cz/common/tmp.gif"WIDTH="64"HEIGHT="64"><br>\
   <input style="text-align: center"type="text"size=4 name="p"value="'..temp..'"> Temperature grade C<br>\
   <input style="text-align: center"type="text"size=4 name="p"value="'..fare..'"> Temperature grade F</font></h3>\
   <IMG SRC="http://esp8266.fancon.cz/common/'..sensorType..'.gif"WIDTH="200"HEIGHT="230"BORDER="2"></body></html>') end
    conn:on("sent",function(conn) conn:close() end)
    end)
end)
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Re: Simple wifi web server - hygrometer with DHT22 sensor

By sxcurtin
- Fri Jan 30, 2015 10:02 pm #8558 Really nice... But I have invalid data. I get -1 for humidity and -3277 for temperature (*C) Tried another sensor (DHT22) no joy, same values with no sensor present. Not sure what's up. It's as if it's not reading from the sensor at all. I tried the same sensors on an arduino, and they're working fine. Only thing is my ground pin is pin 3 of the sensor, not 4 as most resources say.
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