DHT11 for esp8266 - lua

-- dht11 code for esp8266
-- better approach counting back 40 bits from the last meaningful bit
-- untested yet
-- Kevin D

pin = 4

function ReadData()
 gpio_read=gpio.read
 gpio_write=gpio.write
 h=0
 hl=0
 t=0
 tl=0
 cs=0
 bl=0
 cscalc=0
 offset=0
 data={}
 for j = 1, 50, 1 do
  data[j]=0
 end

 gpio.mode(pin, gpio.OUTPUT)
 gpio.write(pin, gpio.LOW)
 tmr.delay(20000)
 gpio.mode(pin, gpio.INPUT)

 for j=1,50,1 do
  bl=0
  while (gpio_read(pin)==0) do end
  while (gpio_read(pin)==1 and bl<10 ) do
   bl=bl+1
  end
  if(bl>=10) then
   offset=j-1-40
   break
  else
   data[j]=bl
  end
 end

 for i=1,8,1 do
  if (data[i+0+offset]>2) then
   h = h+2^(8-i)
  end
 end

 for i=1,8,1 do
  if (data[i+8+offset]>2) then
   hl = hl+2^(8-i)
  end
 end

 for i=1,8,1 do
  if (data[i+16+offset]>2) then
   t = t+2^(8-i)
  end
 end

 for i=1,8,1 do
  if (data[i+24+offset]>2) then
   tl = tl+2^(8-i)
  end
 end

 for i=1,8,1 do
  if (data[i+32+offset]>2) then
   cs = cs+2^(8-i)
  end
 end

 cscalc=(h+hl+t+tl)%256

 if(cs==cscalc) then
  print ("t: "..t.."."..tl)
  print ("h: "..h.."."..hl)
 else
  print ("erreur checksum")
 end
end

ReadData()