BH1750FVI 是一款 IIC 接口的数字型光强度传感器集成电路。下面介绍一下其在 Windows 10 IoT Core 环境下的用法。
项目运行在 Raspberry Pi 2/3 上，使用 C# 进行编码。
1. 准备
包含 BH1750FVI 的传感器，这里选择的是淘宝上最多的 GY-30；Raspberry Pi 2/3 一块，环境为 Windows 10 IoT Core；公母头杜邦线 4-5 根
2. 连线
Raspberry Pi 2/3 的引脚如图
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由于采用的是 IIC 通信方式，因此我们需要把 GY-30 上的 SDA 与 Pin3 相连，SCL 与 Pin5 相连。VCC 接 3.3V，GND 接地。ADD 决定了传感器的地址，将其连接至 VCC ≥ 0.7 V 的时候，地址为 0x5C，接地时为 0x23。可以不连接。
SDA - Pin3
SCL - Pin5
VCC - 3.3V
GND - GND
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3. 代码
GitHub : https://github.com/ZhangGaoxing/windows-iot-demo/tree/master/BH1750FVIDemo
需要新建一个 Windows 通用 项目 ，并且添加引用 Windows IoT Extensions for the UWP
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在项目中添加一个 C# 代码文件 BH1750FVI.cs，代码如下
using System;
using System.Threading.Tasks;
using Windows.Devices.I2c;
namespace BH1750FVIDemo
{
/// <summary>
/// I2C Address Setting
/// </summary>
enum AddressSetting
{
/// <summary>
/// ADD Pin connect to high power level
/// </summary>
AddPinHigh = 0x5C,
/// <summary>
/// ADD Pin connect to low power level
/// </summary>
AddPinLow = 0x23
};
/// <summary>
/// The mode of measuring
/// </summary>
enum MeasurementMode
{
/// <summary>
/// Start measurement at 1 lx resolution
/// </summary>
ContinuouslyHighResolutionMode = 0x10,
/// <summary>
/// Start measurement at 0.5 lx resolution
/// </summary>
ContinuouslyHighResolutionMode2 = 0x11,
/// <summary>
/// Start measurement at 4 lx resolution
/// </summary>
ContinuouslyLowResolutionMode = 0x13,
/// <summary>
/// Start measurement at 1 lx resolution once
/// </summary>
OneTimeHighResolutionMode = 0x20,
/// <summary>
/// Start measurement at 0.5 lx resolution once
/// </summary>
OneTimeHighResolutionMode2 = 0x21,
/// <summary>
/// Start measurement at 4 lx resolution once
/// </summary>
OneTimeLowResolutionMode = 0x23
}
/// <summary>
/// Setting light transmittance
/// </summary>
enum LightTransmittance
{
Fifty,
Eighty,
Hundred,
Hundred_Twenty,
Hundred_Fifty,
Two_Hundred
}
class BH1750FVI
{
I2cDevice sensor;
private byte sensorAddress;
private byte sensorMode;
private byte sensorResolution = 1;
private double sensorTransmittance = 1;
private byte registerHighVal = 0x42;
private byte registerLowVal = 0x65;
/// <summary>
/// Constructor
/// </summary>
/// <param name="address">Enumeration type of AddressSetting</param>
/// <param name="mode">Enumeration type of MeasurementMode</param>
public BH1750FVI(AddressSetting address, MeasurementMode mode)
{
sensorAddress = (byte)address;
sensorMode = (byte)mode;
if (mode == MeasurementMode.ContinuouslyHighResolutionMode2 || mode == MeasurementMode.OneTimeHighResolutionMode2)
{
sensorResolution = 2;
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="address">Enumeration type of AddressSetting</param>
/// <param name="mode">Enumeration type of MeasurementMode</param>
/// <param name="transmittance">Enumeration type of LightTransmittance</param>
public BH1750FVI(AddressSetting address, MeasurementMode mode, LightTransmittance transmittance)
{
sensorAddress = (byte)address;
sensorMode = (byte)mode;
if (mode == MeasurementMode.ContinuouslyHighResolutionMode2 || mode == MeasurementMode.OneTimeHighResolutionMode2)
{
sensorResolution = 2;
}
switch (transmittance)
{
case LightTransmittance.Fifty:
{
registerHighVal = 0x44;
registerLowVal = 0x6A;
sensorTransmittance = 0.5;
}
break;
case LightTransmittance.Eighty:
{
registerHighVal = 0x42;
registerLowVal = 0x76;
sensorTransmittance = 0.8;
}
break;
case LightTransmittance.Hundred:
{
registerHighVal = 0x42;
registerLowVal = 0x65;
}
break;
case LightTransmittance.Hundred_Twenty:
{
registerHighVal = 0x41;
registerLowVal = 0x7A;
sensorTransmittance = 1.2;
}
break;
case LightTransmittance.Hundred_Fifty:
{
registerHighVal = 0x41;
registerLowVal = 0x7E;
sensorTransmittance = 1.5;
}
break;
case LightTransmittance.Two_Hundred:
{
registerHighVal = 0x41;
registerLowVal = 0x73;
sensorTransmittance = 2;
}
break;
}
}
/// <summary>
/// Initialize BH1750FVI
/// </summary>
public async Task InitializeAsync()
{
var settings = new I2cConnectionSettings(sensorAddress);
settings.BusSpeed = I2cBusSpeed.FastMode;
var controller = await I2cController.GetDefaultAsync();
sensor = controller.GetDevice(settings);
sensor.Write(new byte[] { 0x01 });
sensor.Write(new byte[] { registerHighVal });
sensor.Write(new byte[] { registerLowVal });
}
/// <summary>
/// Read data from BH1750FVI
/// </summary>
/// <returns>A double type contains data</returns>
public double Read()
{
byte[] readBuf = new byte[2];
sensor.WriteRead(new byte[] { sensorMode }, readBuf);
byte temp = readBuf[0];
readBuf[0] = readBuf[1];
readBuf[1] = temp;
double result = BitConverter.ToUInt16(readBuf, 0) / (1.2 * sensorResolution * sensorTransmittance);
return result;
}
/// <summary>
/// Cleanup
/// </summary>
public void Dispose()
{
sensor.Dispose();
}
}
}
下面解释如何使用
代码包含三个枚举类型，两个构造函数，三个方法。
第一步调用构造函数将 BH1750FVI 实例化。
第二步调用 InitializeAsync() 初始化 I2C 设备
第三步调用 Read() 读取数据，返回的是一个 double 类型的值
当需要关闭设备时，调用 Dispose()
