script/libs/bh1750.lua

   1 --[[
   2 @module bh1750
   3 @summary bh1750 数字型光强度传感器
   4 @version 1.0
   5 @date    2022.03.15
   6 @author  Dozingfiretruck
   7 @usage
   8 --注意:因使用了sys.wait()所有api需要在协程中使用
   9 -- 用法实例
  10 local bh1750 = require "bh1750"
  11 i2cid = 0
  12 i2c_speed = i2c.FAST
  13 sys.taskInit(function()
  14     i2c.setup(i2cid,i2c_speed)
  15     bh1750.init(i2cid)--初始化,传入i2c_id
  16     while 1 do
  17         local bh1750_data = bh1750.read_light()
  18         log.info("bh1750_read_light", bh1750_data)
  19         sys.wait(1000)
  20     end
  21 end)
  22 ]]
  23
  24 local bh1750 = {}
  25
  26 local sys = require "sys"
  27
  28 local i2cid
  29
  30 local BH1750_ADDRESS_AD0_LOW     =   0x23 -- address pin low (GND), default for InvenSense evaluation board
  31 local BH1750_ADDRESS_AD0_HIGH    =   0x24 -- address pin high (VCC)
  32
  33 local i2cslaveaddr = BH1750_ADDRESS_AD0_LOW
  34
  35 -- bh1750 registers define
  36 local BH1750_POWER_DOWN             =   0x00    -- power down
  37 local BH1750_POWER_ON                   =   0x01        -- power on
  38 local BH1750_RESET                          =   0x07    -- reset
  39 local BH1750_CON_H_RES_MODE         =   0x10    -- Continuously H-Resolution Mode
  40 local BH1750_CON_H_RES_MODE2    =   0x11        -- Continuously H-Resolution Mode2
  41 local BH1750_CON_L_RES_MODE         =   0x13    -- Continuously L-Resolution Mode
  42 local BH1750_ONE_H_RES_MODE         =   0x20    -- One Time H-Resolution Mode
  43 local BH1750_ONE_H_RES_MODE2    =   0x21        -- One Time H-Resolution Mode2
  44 local BH1750_ONE_L_RES_MODE         =   0x23    -- One Time L-Resolution Mode
  45
  46 local function i2c_send(data)
  47     i2c.send(i2cid, i2cslaveaddr, data)
  48 end
  49
  50 local function i2c_recv(num)
  51     local revData = i2c.recv(i2cid, i2cslaveaddr, num)
  52     return revData
  53 end
  54
  55 function bh1750.power_on()
  56     i2c_send(BH1750_POWER_ON)
  57 end
  58
  59 function bh1750.power_down()
  60     i2c_send(BH1750_POWER_DOWN)
  61 end
  62
  63 local function bh1750_set_measure_mode(mode,time)
  64     i2c_send(BH1750_RESET)
  65     i2c_send(mode)
  66     sys.wait(time)
  67 end
  68
  69 --[[
  70 bh1750初始化
  71 @api bh1750.init(i2c_id)
  72 @number 所在的i2c总线id
  73 @return bool   成功返回true
  74 @usage
  75 bh1750.init(0)
  76 ]]
  77 function bh1750.init(i2c_id)
  78     i2cid = i2c_id
  79     bh1750.power_on()
  80     log.info("bh1750 init_ok")
  81     return true
  82 end
  83
  84 --[[
  85 获取bh1750数据
  86 @api bh1750.read_light()
  87 @return number 光照强度数据, 若读取失败会返回nil
  88 @usage
  89 local bh1750_data = bh1750.read_light()
  90 log.info("bh1750_read_light", bh1750_data)
  91 ]]
  92 function bh1750.read_light()
  93     bh1750_set_measure_mode(BH1750_CON_H_RES_MODE, 180)
  94     -- local _,light = pack.unpack(i2c_recv(2),">h") -- 极端情况下数据溢出导致的光照出现负值, 如string.toHex(i2c_recv(2)) == "FFFF"
  95     local _,light = pack.unpack(i2c_recv(2),">H")
  96     if light then
  97         return light / 1.2
  98     end
  99 end
 100
 101 return bh1750
 102
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 105