added API to support infrared channel values

Author: Rocketct

examples/ReadIR/ReadIR.ino

@@ -0,0 +1,36 @@
+/*
+  Arduino LTR381RGB - Read Infrared values
+
+  This example reads the IR channel values from the LTR381RGB
+  sensor and continuously prints them to the Serial Monitor
+  or Serial Plotter.
+
+  The circuit:
+  - Arduino Uno WiFi R4
+  - Modulino light sensor
+
+  This example code is in the public domain.
+*/
+
+#include "Arduino_LTR381RGB.h"
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+
+  if (!RGB.begin()) {
+    Serial.println("Failed to initialize rgb sensor!");
+    while (1);
+  }
+}
+
+void loop() {
+  int ir;
+
+  if (RGB.readIR(ir)) {
+    Serial.print("Value: ");
+    Serial.println(ir);
+  }
+
+  delay(1000);
+}

src/LTR381RGB.cpp

@@ -137,6 +137,19 @@ int LTR381RGBClass::readLux(int& lux) {
   return 1;
 }
 
+int LTR381RGBClass::readIR(int& ir) {
+  enableALS();
+  unsigned long start = millis();
+  while(!available() && (millis() - start) < _timeout);
+  uint8_t buf[3] = {0};
+  int res = readRegisters(LTR381RGB_CS_DATA_IR, buf, 3);
+  if(res != 1) {
+    return 0;
+  }
+  ir = buf[2] << 16 | buf[1] << 8 | buf[0];
+
+  return 1;
+}
 
 void LTR381RGBClass::setGain(int gain) {
   writeRegister(LTR381RGB_ALS_CS_GAIN, (0x07 & gain));

src/LTR381RGB.h

@@ -20,7 +20,7 @@ class LTR381RGBClass {
 
     int readAmbientLight(int& lux);
     int readLux(int& lux);
-
+    int readIR(int& ir);
     void setGain(int gain);
     void setADCResolution(int resolution);
     void setMeasurementRate(int rate);