[luatos sensor] 1 light sensing bh1750

1 Preface

Sort out the codes of several sensors .
BMP pressure ：https://doc.openluat.com/wiki/21?wiki_page_id=2729
Compass ：https://doc.openluat.com/wiki/21?wiki_page_id=2750
The light intensity ：https://doc.openluat.com/wiki/21?wiki_page_id=2668
color ：https://doc.openluat.com/wiki/21?wiki_page_id=2746

This chapter is about the light intensity sensor BH1750.

2 Hardware connection

esp32 Only one... Is supported i2c,id by 0
View source code ：https://gitee.com/dreamcmi/LuatOS-ESP32/blob/master/components/luat/port/luat_i2c_esp32.c

3 Official instance code

PROJECT = "sensor"
VERSION = "1.0.0"

require "log"
require "sys"
require "misc"

-- i2c ID
i2cid = 2

-- i2c  rate 
speed = 100000

--  initialization 
function init(address)
    if i2c.setup(i2cid, speed, -1, 1) ~= speed then
        log.error("i2c", "setup fail", addr)
        return
    end
    addr = address
end

--  Reading data 
function send(...)
    sys.wait(10)
    if not addr then 
        log.info("i2c", "addr err")
        return 
    end
    local t = {
    ...}
    if i2c.send(i2cid, addr, t) ~= #t then
        log.error("i2c", "send fail", #t)
        return
    end
    return true
end

--  send data 
function read(n)
    sys.wait(10)
    if not addr then 
        log.info("i2c", "addr err")
        return "\x00" 
    end
    val = i2c.recv(i2cid, addr, n)
    if val and #val>0 then
        return val
    end
    return "\x00"
end

--  Color recognition sensor 
function TCS34725()
    init(0x29) 
    send(0x83, 0xff)
    send(0x81, 0x00)
    send(0x8f, 0x00)
    send(0x80, 0x03)
    sys.wait(800)
    while true do
        sys.wait(1000)
        send(0x94)
        _, c, red, green, blue = pack.unpack(read(8), "<HHHH")
        if red and green and blue then
            lux = (-0.32466 * red) + (1.57837 * green) + (-0.73191 * blue)
            log.info("red", red)
            log.info("green", green)
            log.info("blue", blue)
            log.info("c, lux", c, lux)
        else
            log.info("TCS34725", "err")
        end
    end
end

sys.taskInit(function()
	sys.wait(3000)
	TCS34725()
end)

sys.init(0, 0)
sys.run()

4 Change code

sen_BH1750.lua

---  Module function ：BH1750
-- @module BH1750
-- @author Dozingfiretruck ,youkai
-- @license MIT
-- @copyright OpenLuat.com
-- @release 2021.03.14

--  Source code https://doc.openluat.com/wiki/21?wiki_page_id=2668

BH1750_i2c_id = 0 --BH1750_i2c_id esp32 i2c 0

BH1750_ADDRESS_AD0_LOW     =   0x23 -- address pin low (GND), default for InvenSense evaluation board
BH1750_ADDRESS_AD0_HIGH    =   0x24 -- address pin high (VCC)

BH1750_i2c_slaveaddr = BH1750_ADDRESS_AD0_LOW     -- ADDRES

-- BH1750 registers define
BH1750_POWER_DOWN   	    =   0x00	-- power down
BH1750_POWER_ON			=   0x01	-- power on
BH1750_RESET			    =   0x07	-- reset
BH1750_CON_H_RES_MODE	    =   0x10	-- Continuously H-Resolution Mode
BH1750_CON_H_RES_MODE2	=   0x11	-- Continuously H-Resolution Mode2
BH1750_CON_L_RES_MODE	    =   0x13	-- Continuously L-Resolution Mode
BH1750_ONE_H_RES_MODE	    =   0x20	-- One Time H-Resolution Mode
BH1750_ONE_H_RES_MODE2	=   0x21	-- One Time H-Resolution Mode2
BH1750_ONE_L_RES_MODE	    =   0x23	-- One Time L-Resolution Mode

local function BH1750_i2c_send(data)
    i2c.send(BH1750_i2c_id, BH1750_i2c_slaveaddr, data)
end
local function BH1750_i2c_recv(num)
    revData = i2c.recv(BH1750_i2c_id, BH1750_i2c_slaveaddr, num)
    return revData
end

local function BH1750_power_on()
    BH1750_i2c_send(BH1750_POWER_ON)
end

local function BH1750_power_down()
    BH1750_i2c_send(BH1750_POWER_DOWN)
end

local function BH1750_set_measure_mode(mode,time)
    BH1750_i2c_send(BH1750_RESET)
    BH1750_i2c_send(mode)
    sys.wait(time)
end

local function BH1750_read_light()
    BH1750_set_measure_mode(BH1750_CON_H_RES_MODE2, 180)
    _,light = pack.unpack(BH1750_i2c_recv(2),">h")
    light = light / 1.2
    return light;
end

function BH1750_init(t_spi_id)
    BH1750_i2c_id = t_spi_id
    log.info("BH1750_i2c_id",BH1750_i2c_id)
    if i2c.setup(t_spi_id,i2c.SLOW) ~= i2c.SLOW then
        log.error("I2c.init","fail")
        return
    else
        print("BH1750_init ok.")
    end
    BH1750_power_on()
end

function BH1750_get()
    log.info("BH1750_read_light", BH1750_read_light()*10)
    sys.wait(100)
end

main.lua

PROJECT = "sensor"
VERSION = "1.0.0"

_G.sys = require("sys")

require("sen_BH1750")       --  Light sense 

--  load I²C Function test module 
T1_BH1750 = 1

-- i2c ID
esp32_i2c_id = 0        -- esp32 Only one way i2c, id by 0

sys.taskInit(function()
    if T1_BH1750 == 1 then
        BH1750_init(esp32_i2c_id)
    end
    
    while 1 do
        if T1_BH1750 == 1 then
            BH1750_get()
        end
        sys.wait(100)
    end
end)

sys.run()

result