BH1750 Light Intensity Detection Sensor

Uses the original ROHM BH1750FVI chip. Power supply: 3-5V, illuminance range: 0-65535lx. The sensor has a built-in 16-bit AD converter with direct digital output, omitting complex calculations and calibration. It does not distinguish ambient light sources and has spectral characteristics close to visual sensitivity, enabling high-precision measurement of a wide range of brightness at 1 lux. Standard NXP IIC communication protocol; the module includes communication level shifting inside, allowing direct connection to 5V microcontroller IO.

Module Source

Purchase link: https://detail.tmall.com/item.htm?_u=52t4uge534a7&id=598334245306&spm=a1z09.2.0.0.47582e8dxs1caw Materials download link: https://pan.baidu.com/s/13bVmmj0eM22mT8pBusjIyQ?pwd=8889 Extraction code: 8889

Specifications

Operating voltage: 3-5V Operating current: 200uA Detection range: 1~65536 lx Module dimensions: 32.6mm x 15.2mm x 11.6mm Output method: IIC Number of pins: 5 Pin

View Materials

Measurement steps:

1. After the module is powered on, it enters power-down mode. It needs to be started by sending a Power On command via IIC.
2. After the module is started, send a measurement command via IIC to perform measurement.
3. The measurement commands include single-shot measurement and continuous measurement. After the measurement is completed, it enters power-down mode again.

The values corresponding to each command are shown in the table below. The ones we use are: Power On (0x01): Start the module and have it wait for a measurement command. Continuously H-Resolution Mode (0X10): Start measurement with 1 LX resolution. The measurement time is typically 120ms (the manual recommends using this command). One Time H-Resolution Mode (0X20): Start measurement with 1 lx resolution. The measurement time is typically 120ms. After completion, the system automatically sets to "power-down" mode.

Send sequence: Start signal -> Send device address + write -> Wait for module ACK -> Send command -> Wait for module ACK -> Stop signal. Read sequence: Start signal -> Send device address + read -> Wait for module ACK -> Receive high 8 bits of data -> Master sends ACK -> Receive low 8 bits of data -> Master sends NACK -> Stop signal. After reading is complete, combine the high and low bits of the data and divide by 1.2 to obtain the light intensity data.

Porting Process

Pin Selection

Port to Project

Our goal is to port the example to the ESP32-S3 dev board. Complete driver code has been provided for you. Follow the steps below to complete the porting. For detailed instructions on creating folders and new .c and .h files, refer to section 1.4.2 in the [DHT11 Temperature and Humidity Sensor] chapter; we will not repeat it here. The only difference is that we replace the file names bsp_dht11.c and bsp_dht11.h with bsp_bh1750.c and bsp_bh1750.h, and rename the folder to BH1750.

Write Code

In the file bsp_bh1750.c, write the following code.

/*
 * LCSC-Openkits (LCKFB) software and hardware materials and related expansion board software and hardware materials are all open source on the official website.
 * Dev board official website: www.lckfb.com
 * Technical support resides on the forum; any technical questions are welcome for exchange and learning at any time.
 * LCKFB Forum: club.szlcsc.com
 * Follow our Bilibili account: [LCSC-Openkits (LCKFB)] to keep up with our latest updates!
 * We do not make money by selling boards; we take cultivating engineers as our mission.
 * Change Logs:
 * Date           Author       Notes
 * 2024-01-05     LCKFB-lp    first version
 */

#include "bsp_bh1750.h"
#include "stdio.h"

unsigned char BUF[8];                         //Receive data buffer

void delay_ms(unsigned int ms)
{
    vTaskDelay(ms / portTICK_PERIOD_MS);
}
void delay_us(unsigned int us)
{
    ets_delay_us(us);
}
void delay_1ms(unsigned int ms)
{
    vTaskDelay(ms / portTICK_PERIOD_MS);
}
void delay_1us(unsigned int us)
{
    ets_delay_us(us);
}
/******************************************************************
 * Function Name: GY30_GPIO_Init
 * Function Description: MLX90614 pin initialization
 * Function Parameters: None
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void GY30_GPIO_Init(void)
{
    gpio_config_t lll_config = {
        .pin_bit_mask = (1ULL<<BH1750_SCL_PIN)|(1ULL<<BH1750_SDA_PIN), // Configure pins
        .mode =GPIO_MODE_OUTPUT,                   // Output mode
        .pull_up_en = GPIO_PULLUP_ENABLE,         // Enable pull-up
        .pull_down_en = GPIO_PULLDOWN_DISABLE,    // Disable pull-down
        .intr_type = GPIO_INTR_DISABLE            // Disable pin interrupt
    };
    gpio_config(&lll_config);
}

/******************************************************************
 * Function Name: IIC_Start
 * Function Description: IIC start sequence
 * Function Parameters: None
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void IIC_Start(void)
{
        SDA_OUT();

        SDA(1);
        delay_us(5);
        SCL(1);
        delay_us(5);

        SDA(0);
        delay_us(5);
        SCL(0);
        delay_us(5);

}
/******************************************************************
 * Function Name: IIC_Stop
 * Function Description: IIC stop signal
 * Function Parameters: None
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void IIC_Stop(void)
{
        SDA_OUT();
        SCL(0);
        SDA(0);

        SCL(1);
        delay_us(5);
        SDA(1);
        delay_us(5);

}

/******************************************************************
 * Function Name: IIC_Send_Ack
 * Function Description: Master sends ACK or NACK signal
 * Function Parameters: 0=send ACK  1=send NACK
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void IIC_Send_Ack(unsigned char ack)
{
        SDA_OUT();
        SCL(0);
        SDA(0);
        delay_us(5);
        if(!ack) SDA(0);
        else         SDA(1);
        SCL(1);
        delay_us(5);
        SCL(0);
        SDA(1);
}

/******************************************************************
 * Function Name: I2C_WaitAck
 * Function Description: Wait for slave acknowledge
 * Function Parameters: None
 * Function Return: 0=ACK received  1=timeout, no ACK
 * Author: LC
 * Notes: None
******************************************************************/
unsigned char I2C_WaitAck(void)
{

    char ack = 0;
    unsigned char ack_flag = 10;
    SCL(0);
    SDA(1);
    SDA_IN();
    delay_us(5);
    SCL(1);
    delay_us(5);

    while( (SDA_GET()==1) && ( ack_flag ) )
    {
            ack_flag--;
            delay_us(5);
    }

    if( ack_flag <= 0 )
    {
            IIC_Stop();
            return 1;
    }
    else
    {
            SCL(0);
            SDA_OUT();
    }
    return ack;
}

/******************************************************************
 * Function Name: Send_Byte
 * Function Description: Write one byte
 * Function Parameters: dat=data to write
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void Send_Byte(uint8_t dat)
{
        int i = 0;
        SDA_OUT();
        SCL(0);//Pull clock low to start data transfer

        for( i = 0; i < 8; i++ )
        {
                SDA( (dat & 0x80) >> 7 );
                delay_us(1);
                SCL(1);
                delay_us(5);
                SCL(0);
                delay_us(5);
                dat<<=1;
        }
}

/******************************************************************
 * Function Name: Read_Byte
 * Function Description: IIC read sequence
 * Function Parameters: None
 * Function Return: Data read
 * Author: LC
 * Notes: None
******************************************************************/
unsigned char Read_Byte(void)
{
        unsigned char i,receive=0;
        SDA_IN();//Set SDA as input
        for(i=0;i<8;i++ )
        {
            SCL(0);
            delay_us(5);
            SCL(1);
            delay_us(5);
            receive<<=1;
            if( SDA_GET() )
            {
            receive|=1;
            }
            delay_us(5);
        }
        SCL(0);
        return receive;
}

/******************************************************************
 * Function Name: Single_Write
 * Function Description: Write command to BH1750
 * Function Parameters: REG_Address=command to write
 * Function Return: 0=write success  1=device address error (module not recognized)  2=command error
 * Author: LC
 * Notes: None
******************************************************************/
char Single_Write_BH1750(uint8_t REG_Address)
{
        IIC_Start();                        //Start signal
        Send_Byte(SlaveAddress);            //Send device address + write
        if( I2C_WaitAck() != 0 )return 1;
        Send_Byte(REG_Address);             //Internal register address
        if( I2C_WaitAck() != 0 )return 2;
        IIC_Stop();                         //Send stop signal
        return 0;
}

/******************************************************************
 * Function Name: Multiple_read_BH1750
 * Function Description: Read internal data of BH1750
 * Function Parameters: None
 * Function Return: Illuminance, unit: lx
 * Author: LC
 * Notes: None
******************************************************************/
float Multiple_read_BH1750(void)
{
       uint16_t dis_data=0;
       uint8_t dat_buff[2];

       IIC_Start();                            //Start signal
       Send_Byte(SlaveAddress+1);              //Send device address + read
       I2C_WaitAck();

       dat_buff[0] = Read_Byte();              //Read high 8 bits
       IIC_Send_Ack(0);                        //Respond ACK
       dat_buff[1] = Read_Byte();              //Read low 8 bits
       IIC_Send_Ack(1);                        //Respond NACK
       IIC_Stop();                             //Stop signal

       //Combine data, i.e. illuminance data
       dis_data=( dat_buff[0] << 8 ) + dat_buff[1];
       return ((float)dis_data/1.2);
}

/******************************************************************
 * Function Name: GY30_Init
 * Function Description: Initialize BH1750
 * Function Parameters: None
 * Function Return: None
 * Author: LC
 * Notes: None
******************************************************************/
void GY30_Init(void)
{
       GY30_GPIO_Init();
       Single_Write_BH1750(0x01);//Power on
}

In the file bsp_bh1750.h, write the following code.

/*
 * LCSC-Openkits (LCKFB) software and hardware materials and related expansion board software and hardware materials are all open source on the official website.
 * Dev board official website: www.lckfb.com
 * Technical support resides on the forum; any technical questions are welcome for exchange and learning at any time.
 * LCKFB Forum: club.szlcsc.com
 * Follow our Bilibili account: [LCSC-Openkits (LCKFB)] to keep up with our latest updates!
 * We do not make money by selling boards; we take cultivating engineers as our mission.
 * Change Logs:
 * Date           Author       Notes
 * 2024-01-05     LCKFB-lp    first version
 */
#ifndef _BSP_GY30_H_
#define _BSP_GY30_H_

#include <stdio.h>
#include <inttypes.h>
#include "sdkconfig.h"
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_rom_sys.h"
#include "esp_timer.h"
#include "driver/uart.h"
#include "rom/ets_sys.h"
#include "esp_system.h"
#include "driver/gptimer.h"
#include "esp_log.h"
#include "freertos/queue.h"
#include "driver/spi_master.h"
#include "nvs_flash.h"
#include "esp_adc/adc_cali_scheme.h"
#include "esp_adc/adc_cali.h"
#include "driver/adc.h"
#include "esp_adc_cal.h"

//Port porting
#define BH1750_SCL_PIN          1
#define BH1750_SDA_PIN          2

//Set SDA output mode
#define SDA_OUT()        gpio_set_direction(BH1750_SDA_PIN,GPIO_MODE_OUTPUT)
//Set SDA input mode
#define SDA_IN()         gpio_set_direction(BH1750_SDA_PIN,GPIO_MODE_INPUT)
//Get SDA pin level change
#define SDA_GET()        gpio_get_level(BH1750_SDA_PIN)
//SDA and SCL output
#define SDA(x)           gpio_set_level(BH1750_SDA_PIN, (x?1:0))
#define SCL(x)           gpio_set_level(BH1750_SCL_PIN, (x?1:0))

#define          SlaveAddress   0x46 //Define the slave address of the device on the IIC bus; modify according to the ALT ADDRESS address pin
                              //When the ALT ADDRESS pin is grounded, the address is 0x46; when connected to power, the address is 0xB8

float Multiple_read_BH1750(void);
char Single_Write_BH1750(uint8_t REG_Address);
void GY30_Init(void);

void delay_us(unsigned int us);
void delay_ms(unsigned int ms);
void delay_1us(unsigned int us);
void delay_1ms(unsigned int ms);
#endif

Porting Verification

In the main function of your own project, write the following.

/*
 * LCSC-Openkits (LCKFB) software and hardware materials and related expansion board software and hardware materials are all open source on the official website.
 * Dev board official website: www.lckfb.com
 * Technical support resides on the forum; any technical questions are welcome for exchange and learning at any time.
 * LCKFB Forum: club.szlcsc.com
 * Follow our Bilibili account: [LCSC-Openkits (LCKFB)] to keep up with our latest updates!
 * We do not make money by selling boards; we take cultivating engineers as our mission.
 * Change Logs:
 * Date           Author       Notes
 * 2024-01-05     LCKFB-lp    first version
 */
#include <stdio.h>
#include "bsp_bh1750.h"

void app_main(void)
{
    float temp;
    GY30_Init();
    printf("start\r\n");
    while(1)
    {
        Single_Write_BH1750(0x10);          // Continuous high-resolution mode measurement
        delay_1ms(180);                     //Measurement typically takes 120ms
        temp = Multiple_read_BH1750();      //Read out data
        printf("illuminance = %.2f lx\r\n",temp);
        delay_1ms(500);
    }
}

Power-on effect

Driver code:

File Download

📌 Materials Download Center (click to jump)

📌 In the Materials Download Center -> Module Porting Materials Download, inside the compressed package of this chapter.