-- Measure temperature, humidity and post data to thingspeak.com

-- 2014 OK1CDJ

-- DHT11 code is from esp8266.com

---Sensor DHT11 is conntected to GPIO2

pin = 2

Humidity = 0

HumidityDec=0

Temperature = 0

TemperatureDec=0

Checksum = 0

ChecksumTest=0

function getTemp()

Humidity = 0

HumidityDec=0

Temperature = 0

TemperatureDec=0

Checksum = 0

ChecksumTest=0

--Data stream acquisition timing is critical. There's

--barely enough speed to work with to make this happen.

--Pre-allocate vars used in loop.

bitStream = {}

for j = 1, 40, 1 do

bitStream[j]=0

end

bitlength=0

gpio.mode(pin, gpio.OUTPUT)

gpio.write(pin, gpio.LOW)

tmr.delay(20000)

--Use Markus Gritsch trick to speed up read/write on GPIO

gpio_read=gpio.read

gpio_write=gpio.write

gpio.mode(pin, gpio.INPUT)

--bus will always let up eventually, don't bother with timeout

while (gpio_read(pin)==0 ) do end

c=0

while (gpio_read(pin)==1 and c<100) do c=c+1 end

--bus will always let up eventually, don't bother with timeout

while (gpio_read(pin)==0 ) do end

c=0

while (gpio_read(pin)==1 and c<100) do c=c+1 end

--acquisition loop

for j = 1, 40, 1 do

while (gpio_read(pin)==1 and bitlength<10 ) do

bitlength=bitlength+1

end

bitStream[j]=bitlength

bitlength=0

--bus will always let up eventually, don't bother with timeout

while (gpio_read(pin)==0) do end

end

--DHT data acquired, process.

for i = 1, 8, 1 do

if (bitStream[i+0] > 2) then

Humidity = Humidity+2^(8-i)

end

end

for i = 1, 8, 1 do

if (bitStream[i+8] > 2) then

HumidityDec = HumidityDec+2^(8-i)

end

end

for i = 1, 8, 1 do

if (bitStream[i+16] > 2) then

Temperature = Temperature+2^(8-i)

end

end

for i = 1, 8, 1 do

if (bitStream[i+24] > 2) then

TemperatureDec = TemperatureDec+2^(8-i)

end

end

for i = 1, 8, 1 do

if (bitStream[i+32] > 2) then

Checksum = Checksum+2^(8-i)

end

end

ChecksumTest=(Humidity+HumidityDec+Temperature+TemperatureDec) % 0xFF

print ("Temperature: "..Temperature.."."..TemperatureDec)

print ("Humidity: "..Humidity.."."..HumidityDec)

print ("ChecksumReceived: "..Checksum)

print ("ChecksumTest: "..ChecksumTest)

end

--- Get temp and send data to thingspeak.com

function sendData()

getTemp()

-- conection to thingspeak.com

print("Sending data to thingspeak.com")

conn=net.createConnection(net.TCP, 0)

conn:on("receive", function(conn, payload) print(payload) end)

-- api.thingspeak.com 184.106.153.149

conn:connect(80,'192.168.0.107')

conn:send("GET /update?key=DBKBFHIR0L020NIQ&field1="..Temperature.."."..TemperatureDec.."&field2="..Humidity.."."..HumidityDec.." HTTP/1.1\r\n")

conn:send("Host: api.thingspeak.com\r\n")

conn:send("Accept: */*\r\n")

conn:send("User-Agent: Mozilla/4.0 (compatible; esp8266 Lua; Windows NT 5.1)\r\n")

conn:send("\r\n")

conn:on("sent",function(conn)

print("Closing connection")

conn:close()

end)

conn:on("disconnection", function(conn)

print("Got disconnection...")

end)

end

-- send data every X ms to thing speak

--tmr.alarm(2, 60000, 1, function() sendData() end )

tmr.alarm(2, 10000, 1,

function()

--sendData()

getTemp()

end )