Diff: TCS3472_I2C.cpp

Revision:

7:ab9ff8738826

Parent:

6:6d5bb4ad7d6e

Child:

8:764a98777c11

--- a/TCS3472_I2C.cpp	Thu Apr 24 09:14:25 2014 +0000
+++ b/TCS3472_I2C.cpp	Sun Apr 30 08:00:52 2017 +0000
@@ -43,12 +43,15 @@
 void TCS3472_I2C::getAllColors( int* readings ){
     char buffer[8] = { 0 };
 
-    readMultipleRegisters( CDATA, buffer, 8 );
-
-    readings[0] = (int)buffer[1] << 8 | (int)buffer[0];
-    readings[1] = (int)buffer[3] << 8 | (int)buffer[2];
-    readings[2] = (int)buffer[5] << 8 | (int)buffer[4];
-    readings[3] = (int)buffer[7] << 8 | (int)buffer[6];
+    if (readMultipleRegisters( CDATA, buffer, 8 ) ==0){
+        readings[0] = (int)buffer[1] << 8 | (int)buffer[0];//c
+        readings[1] = (int)buffer[3] << 8 | (int)buffer[2];//r
+        readings[2] = (int)buffer[5] << 8 | (int)buffer[4];//g
+        readings[3] = (int)buffer[7] << 8 | (int)buffer[6];//b
+    }
+    else{
+        readings[0] = 0;readings[1] = 0;readings[2] = 0;readings[3] = 0;
+    }
 }
 
 int TCS3472_I2C::getClearData(){
@@ -178,7 +181,7 @@
 }
 
 int TCS3472_I2C::setIntegrationTime( const float itime ){
-    char atime = 256 - roundTowardsZero( itime / 2.4 ); // rounding ensures nearest value of atime is used
+    char atime = 256 - (int)roundTowardsZero( itime / 2.4 ); // rounding ensures nearest value of atime is used
     int ack = writeSingleRegister( ATIME, atime );
     return ack;
 }
@@ -447,4 +450,85 @@
         result = ceil(value);
     }
     return result;
+}
+
+int TCS3472_I2C::calculateColorTemperature(int r, int g, int b)
+{
+  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 * r) + (1.54924F * g) + (-0.95641F * b);
+  Y = (-0.32466F * r) + (1.57837F * g) + (-0.73191F * b);
+  Z = (-0.68202F * r) + (0.77073F * g) + ( 0.56332F * b);
+
+  /* 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 = -(449.0F * powf(n, 3)) + (3525.0F * powf(n, 2)) - (6823.3F * n) + 5520.33F;
+
+  /* Return the results in degrees Kelvin */
+  return (int)cct;
+}
+
+float TCS3472_I2C::calculateChromaticityX(int r, int g, int b)
+{
+  float X, Y, Z;      /* RGB to XYZ correlation      */
+  float xc, yc;       /* Chromaticity co-ordinates   */
+
+  /* 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 * r) + (1.54924F * g) + (-0.95641F * b);
+  Y = (-0.32466F * r) + (1.57837F * g) + (-0.73191F * b);
+  Z = (-0.68202F * r) + (0.77073F * g) + ( 0.56332F * b);
+
+  /* 2. Calculate the chromaticity co-ordinates      */
+  xc = (X) / (X + Y + Z);
+  yc = (Y) / (X + Y + Z);
+
+  /* Return the results in degrees Kelvin */
+  return (float)xc;
+}
+float TCS3472_I2C::calculateChromaticityY(int r, int g, int b)
+{
+  float X, Y, Z;      /* RGB to XYZ correlation      */
+  float xc, yc;       /* Chromaticity co-ordinates   */
+
+  /* 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 * r) + (1.54924F * g) + (-0.95641F * b);
+  Y = (-0.32466F * r) + (1.57837F * g) + (-0.73191F * b);
+  Z = (-0.68202F * r) + (0.77073F * g) + ( 0.56332F * b);
+
+  /* 2. Calculate the chromaticity co-ordinates      */
+  xc = (X) / (X + Y + Z);
+  yc = (Y) / (X + Y + Z);
+
+  /* Return the results in degrees Kelvin */
+  return (float)yc;
+}
+
+int TCS3472_I2C::calculateLux(int r, int g, int b)
+{
+  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 * r) + (1.57837F * g) + (-0.73191F * b);
+
+  return (int)illuminance;
 }
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