The Bh1745 is a digital color sensor able to detect 3 distinct channels of light (red, green, blue) and is most suitable to obtain the illuminance and color temperature of ambient light. The device can detect light intensity in a range of 0.005 to 40 000 lux.
The datasheet can be found here.
The easiest way to use this library is by getting it from nuget: https://www.nuget.org/packages/BH1745Driver/
This driver is also included in the Iot.Device.Bindings library with many other device bindings.
You can either use the default settings of the sensor or change them for more precise results.
To use the default settings you could do something like this:
class Program
{
static void Main(string[] args)
{
// bus id on the raspberry pi 3
const int busId = 1;
// create device
var i2cSettings = new I2cConnectionSettings(busId, Bh1745.DefaultI2cAddress);
var i2cDevice = I2cDevice.Create(i2cSettings);
using var i2cBh1745 = new Bh1745(i2cDevice);
// wait for first measurement
Task.Delay(i2cBh1745.MeasurementTime.ToMilliseconds()).Wait();
while (true)
{
var color = i2cBh1745.GetCompensatedColor();
Console.WriteLine("RGB color read: #{0:X2}{1:X2}{2:X2}", color.R, color.G, color.B);
Console.WriteLine($"Raw illumination value: {i2cBh1745.ReadClearDataRegister()}");
Task.Delay(i2cBh1745.MeasurementTime.ToMilliseconds()).Wait();
}
}
}To use your custom settings you could do something like this:
class Program
{
static void Main(string[] args)
{
// bus id on the raspberry pi 3
const int busId = 1;
// create device
var i2cSettings = new I2cConnectionSettings(busId, Bh1745.DefaultI2cAddress);
var i2cDevice = I2cDevice.Create(i2cSettings);
using var i2cBh1745 = new Bh1745(i2cDevice);
// multipliers affect the compensated values, these can be used to gain better results
i2cBh1745.ChannelCompensationMultipliers.Red = 2.5;
i2cBh1745.ChannelCompensationMultipliers.Green = 0.9;
i2cBh1745.ChannelCompensationMultipliers.Blue = 1.9;
i2cBh1745.ChannelCompensationMultipliers.Clear = 9.5;
// set custom measurement time
i2cBh1745.MeasurementTime = MeasurementTime.Ms1280;
// interrupt functionality is detailed in the datasheet
// Reference: https://www.mouser.co.uk/datasheet/2/348/bh1745nuc-e-519994.pdf (page 13)
i2cBh1745.LowerInterruptThreshold = 0xABFF;
i2cBh1745.HigherInterruptThreshold = 0x0A10;
i2cBh1745.LatchBehavior = LatchBehavior.LatchEachMeasurement;
i2cBh1745.InterruptPersistence = InterruptPersistence.UpdateMeasurementEnd;
i2cBh1745.InterruptIsEnabled = true;
// wait for first measurement
Task.Delay(i2cBh1745.MeasurementTime.ToMilliseconds()).Wait();
while (true)
{
var color = i2cBh1745.GetCompensatedColor();
if (!i2cBh1745.ReadMeasurementIsValid())
{
Console.WriteLine("Measurement was not valid!");
continue;
}
Console.WriteLine("RGB color read: #{0:X2}{1:X2}{2:X2}", color.R, color.G, color.B);
Console.WriteLine($"Raw illumination value: {i2cBh1745.ReadClearDataRegister()}");
Task.Delay(i2cBh1745.MeasurementTime.ToMilliseconds()).Wait();
}
}
}You can find these examples in the samples folder.