This document discusses infrared (IR) sensors and their operation. It explains that IR sensors contain an IR LED that emits IR light and an IR phototransistor that detects reflected IR light. The phototransistor acts as a light-controlled variable resistor, increasing conductivity as more light is received. The document also provides code to vary the intensity of RGB LEDs using light readings from an LDR light sensor. It initializes RGB pins as outputs and takes light readings from the LDR to set the brightness of each color.

1. R-tist

2. WHAT IS SENSOR???

3. RGB
REDD5 BLUE
D3
GREEN
D6

5.  See from top to both Led .
 You will see black spot on one led.
 On another one you will see grey spot.
 The led consisting of black spot is the iR
receiver (ir transister).
 Another one is ir emmiter.
 If you see only white spot then it is normal
led.

7.  Ir sensor work on property of ir light that ir
light absorbed by black surface and totally
reflected by white surface.
 Ir led emit ir light which is reflected by
surface is absorbed by ir transistor(ir
receiver).
 Ir receiver work on property that when light
fall on an transister on his base emitter resion
than its CE current increases due to emition
of electron.

8.  The ir receiver work on reverse biased.

9.  Ldr work on the principle of that when light
on the metal its resistance decreases.

12. Program on variation of intensity of RGB using LDR sensor.

13.  int sec1=3;  void loop()
 int sec2=5;  {
 int sec3=6;  sem` 1 21` =
 int temp=A3; analogRead(temp);
 int sem; 
 analogWrite(3,sem);
 void setup() 
 {  analogWrite(5,sem);
 pinMode(3, OUTPUT); 
 pinMode(5, OUTPUT);  analogWrite(6,sem);
 pinMode(6, OUTPUT); 
 }  }