private async Task <LightData> ReadLightData()
{
LightData ld = null;
try
{
if (colorSensor == null)
{
colorSensor = new TCS34725();
await colorSensor.Initialize();
}
//Read the approximate color from the sensor
string colorRead = await colorSensor.getClosestColor();
RgbData rgb = await colorSensor.getRgbData();
float lux = TCS34725.getLuxSimple(rgb);
ld = new LightData();
ld.Created = DateTime.Now;
ld.rgbData = rgb;
ld.Lux = lux;
ld.ColorTempinK = TCS34725.calculateColorTemperature(rgb);
Debug.WriteLine("Current lux: " + lux);
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
return(ld);
}
//public static float getLux(RgbData rgb)
//{
// float illuminance;
// float ir;
// ir = (rgb.Red + rgb.Green + rgb.Blue)
// return illuminance;
//}
public static float calculateColorTemperature(RgbData rgb)
{
float X, Y, Z; /* RGB to XYZ correlation */
float xc, yc; /* Chromaticity co-ordinates */
float n; /* McCamy's formula */
float cct;
/* 1. Map RGB values to their XYZ counterparts. */
/* Based on 6500K fluorescent, 3000K fluorescent */
/* and 60W incandescent values for a wide range. */
/* Note: Y = Illuminance or lux */
X = (-0.14282F * rgb.Red) + (1.54924F * rgb.Green) + (-0.95641F * rgb.Blue);
Y = (-0.32466F * rgb.Red) + (1.57837F * rgb.Green) + (-0.73191F * rgb.Blue);
Z = (-0.68202F * rgb.Red) + (0.77073F * rgb.Green) + (0.56332F * rgb.Blue);
/* 2. Calculate the chromaticity co-ordinates */
xc = (X) / (X + Y + Z);
yc = (Y) / (X + Y + Z);
/* 3. Use McCamy's formula to determine the CCT */
n = (xc - 0.3320F) / (0.1858F - yc);
/* Calculate the final CCT */
cct = (float)((449.0F * Math.Pow(n, 3)) + (3525.0F * Math.Pow(n, 2)) + (6823.3F * n) + 5520.33F);
/* Return the results in degrees Kelvin */
return(cct);
}
//Method to find the approximate color
public async Task <string> getClosestColor()
{
//Create an object to store the raw color data
RgbData rgbData = await getRgbData();
//Create a variable to store the closest color. Black by default.
KnownColor closestColor = colorList[7];
//Create a variable to store the minimum Euclidean distance between 2 colors
double minDiff = double.MaxValue;
//For every known color, check the Euclidean distance and store the minimum distance
foreach (var color in colorList)
{
Color colorValue = color.colorValue;
double diff = Math.Pow((colorValue.R - rgbData.Red), 2) +
Math.Pow((colorValue.G - rgbData.Green), 2) +
Math.Pow((colorValue.B - rgbData.Blue), 2);
diff = (int)Math.Sqrt(diff);
if (diff < minDiff)
{
minDiff = diff;
closestColor = color;
}
}
//Write the approximate color to the debug console
Debug.WriteLine("Approximate color: " + closestColor.colorName + " - "
+ closestColor.colorValue.ToString());
//Return the approximate color
return(closestColor.colorName);
}
public static float getLuxSimple(RgbData rgb)
{
float illuminance;
/* This only uses RGB ... how can we integrate clear or calculate lux */
/* based exclusively on clear since this might be more reliable? */
illuminance = (-0.32466F * rgb.Red) + (1.57837F * rgb.Green) + (-0.73191F * rgb.Blue);
return(illuminance);
}
//Method to read the RGB data
public async Task <RgbData> getRgbData()
{
//Create an object to store the raw color data
RgbData rgbData = new RgbData();
//First get the raw color data
ColorData colorData = await getRawData();
//Check if clear data is received
if (colorData.Clear > 0)
{
//Find the RGB values from the raw data using the clear data as reference
rgbData.Red = (colorData.Red * 255 / colorData.Clear);
rgbData.Blue = (colorData.Blue * 255 / colorData.Clear);
rgbData.Green = (colorData.Green * 255 / colorData.Clear);
}
//Write the RGB values to the debug console
Debug.WriteLine("RGB Data - red: {0}, green: {1}, blue: {2}", rgbData.Red, rgbData.Green, rgbData.Blue);
//Return the data
return(rgbData);
}
//public static float getLux(RgbData rgb)
//{
// float illuminance;
// float ir;
// ir = (rgb.Red + rgb.Green + rgb.Blue)
// return illuminance;
//}
public static float calculateColorTemperature(RgbData rgb)
{
float X, Y, Z; /* RGB to XYZ correlation */
float xc, yc; /* Chromaticity co-ordinates */
float n; /* McCamy's formula */
float cct;
/* 1. Map RGB values to their XYZ counterparts. */
/* Based on 6500K fluorescent, 3000K fluorescent */
/* and 60W incandescent values for a wide range. */
/* Note: Y = Illuminance or lux */
X = (-0.14282F * rgb.Red) + (1.54924F * rgb.Green) + (-0.95641F * rgb.Blue);
Y = (-0.32466F * rgb.Red) + (1.57837F * rgb.Green) + (-0.73191F * rgb.Blue);
Z = (-0.68202F * rgb.Red) + (0.77073F * rgb.Green) + (0.56332F * rgb.Blue);
/* 2. Calculate the chromaticity co-ordinates */
xc = (X) / (X + Y + Z);
yc = (Y) / (X + Y + Z);
/* 3. Use McCamy's formula to determine the CCT */
n = (xc - 0.3320F) / (0.1858F - yc);
/* Calculate the final CCT */
cct = (float)((449.0F * Math.Pow(n, 3)) + (3525.0F * Math.Pow(n, 2)) + (6823.3F * n) + 5520.33F);
/* Return the results in degrees Kelvin */
return cct;
}
public static float getLuxSimple(RgbData rgb)
{
float illuminance;
/* This only uses RGB ... how can we integrate clear or calculate lux */
/* based exclusively on clear since this might be more reliable? */
illuminance = (-0.32466F * rgb.Red) + (1.57837F * rgb.Green) + (-0.73191F * rgb.Blue);
return illuminance;
}
//Method to read the RGB data
public async Task<RgbData> getRgbData()
{
//Create an object to store the raw color data
RgbData rgbData = new RgbData();
//First get the raw color data
ColorData colorData = await getRawData();
//Check if clear data is received
if (colorData.Clear > 0)
{
//Find the RGB values from the raw data using the clear data as reference
rgbData.Red = (colorData.Red * 255 / colorData.Clear);
rgbData.Blue = (colorData.Blue * 255 / colorData.Clear);
rgbData.Green = (colorData.Green * 255 / colorData.Clear);
}
//Write the RGB values to the debug console
Debug.WriteLine("RGB Data - red: {0}, green: {1}, blue: {2}", rgbData.Red, rgbData.Green, rgbData.Blue);
//Return the data
return rgbData;
}
