nodemcu-firmware/lua_modules/bh1750/bh1750.lua

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2015-01-30 14:20:30 +01:00
-- ***************************************************************************
-- BH1750 module for ESP8266 with nodeMCU
-- BH1750 compatible tested 2015-1-22
--
-- Written by xiaohu
--
-- MIT license, http://opensource.org/licenses/MIT
-- ***************************************************************************
local moduleName = ...
local M = {}
_G[moduleName] = M
--I2C slave address of GY-30
local GY_30_address = 0x23
-- i2c interface ID
local id = 0
--LUX
local l
--CMD
local CMD = 0x10
local init = false
--Make it more faster
local i2c = i2c
function M.init(sda, scl)
i2c.setup(id, sda, scl, i2c.SLOW)
--print("i2c ok..")
init = true
end
local function read_data(ADDR, commands, length)
i2c.start(id)
i2c.address(id, ADDR, i2c.TRANSMITTER)
i2c.write(id, commands)
i2c.stop(id)
i2c.start(id)
i2c.address(id, ADDR,i2c.RECEIVER)
tmr.delay(200000)
c = i2c.read(id, length)
i2c.stop(id)
return c
end
local function read_lux()
dataT = read_data(GY_30_address, CMD, 2)
--Make it more faster
UT = dataT:byte(1) * 256 + dataT:byte(2)
l = (UT*1000/12)
return(l)
end
function M.read()
if (not init) then
print("init() must be called before read.")
else
read_lux()
end
end
function M.getlux()
return l
end
return M