Add two APIs and a example.

uint16_t readIRLuminosity(void), read Infrared channel value only, not convert to lux.
uint16_t readFSpecLuminosity(void) //read Full Spectrum channel value only,  not convert to lux.

Digital_Light_TSL2561.cpp

@@ -71,6 +71,44 @@ void TSL2561_CalculateLux::init()
    writeRegister(TSL2561_Address,TSL2561_Interrupt,0x00);
    writeRegister(TSL2561_Address,TSL2561_Control,0x00);  // POWER Down
 }
+
+
+uint16_t TSL2561_CalculateLux::readIRLuminosity() // read Infrared channel value only, not convert to lux.
+{
+   writeRegister(TSL2561_Address,TSL2561_Control,0x03);  // POWER UP
+   delay(14);
+   getLux();
+
+   writeRegister(TSL2561_Address,TSL2561_Control,0x00);  // POWER Down
+   if(ch1 == 0)
+   { 
+     return 0;
+   }
+   if(ch0/ch1 < 2 && ch0 > 4900)
+   {
+     return -1;  //ch0 out of range, but ch1 not. the lux is not valid in this situation.
+   }
+   return ch1;
+}
+
+uint16_t TSL2561_CalculateLux::readFSpecLuminosity() //read Full Spectrum channel value only,  not convert to lux.
+{
+   writeRegister(TSL2561_Address,TSL2561_Control,0x03);  // POWER UP
+   delay(14);
+   getLux();
+
+   writeRegister(TSL2561_Address,TSL2561_Control,0x00);  // POWER Down
+   if(ch1 == 0)
+   { 
+     return 0;
+   }
+   if(ch0/ch1 < 2 && ch0 > 4900)
+   {
+     return -1;  //ch0 out of range, but ch1 not. the lux is not valid in this situation.
+   }
+   return ch0;
+}
+
 signed long TSL2561_CalculateLux::readVisibleLux()
 {
    writeRegister(TSL2561_Address,TSL2561_Control,0x03);  // POWER UP

Digital_Light_TSL2561.h

@@ -104,6 +104,8 @@ class TSL2561_CalculateLux
 {
  public:
   signed long readVisibleLux();
+  uint16_t readIRLuminosity();
+  uint16_t readFSpecLuminosity();
   unsigned long calculateLux(unsigned int iGain, unsigned int tInt,int iType);
   void getLux(void);
   void init(void);

examples/Digital_Light_Sensor_IR/Digital_Light_Sensor_IR.ino

@@ -0,0 +1,48 @@
+/*
+ * Digital_Light_Sensor.ino
+ * A library for TSL2561
+ *
+ * Copyright (c) 2019 seeed technology inc.
+ * Website    : www.seeed.cc
+ * Author     : hongtai.liu
+ * Create Time: 6/11/2019
+ * Change Log :
+ *
+ * The MIT License (MIT)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <Wire.h>
+#include <Digital_Light_TSL2561.h>
+void setup()
+{
+  Wire.begin();
+  Serial.begin(9600);
+  TSL2561.init();
+}
+
+void loop()
+{
+  Serial.print("The Infrared value is: ");
+  Serial.println(TSL2561.readIRLuminosity());  //read Infrared channel value only, not convert to lux.
+  Serial.print("The Full Spectrum value is: ");
+  Serial.println(TSL2561.readFSpecLuminosity());///read Full Spectrum channel value only,  not convert to lux.
+  delay(1000);
+}

keywords.txt

@@ -23,7 +23,8 @@ DigitalLightISL29035	KEYWORD2
 setFullScaleLuxRangeIndex	KEYWORD2
 setIntegrationTimeIndex	KEYWORD2
 readVisibleLux	KEYWORD2
-readIRLux	KEYWORD2
+readIRLuminosity	KEYWORD2
+readFSpecLuminosity	KEYWORD2
 readEV	KEYWORD2
 test	KEYWORD2