Types of IR sensors

   
   In the last article covered IR sensor definition, principle and working. In today's podcast let's discussing types of IR sensors. 

   If the component has types, it may differ according to the vivid aspects. So, similarly, here IR sensor has two types of aspects. Those are

According to the function of IR sensor has two types, those are

1. Thermal Infrared Sensor.
2. Quantum Infrared Sensor.

If going through the working mechanism, again it has two types, those are
1. Active Infrared Sensor.2. Passive Infrared Sensor.
Let's discuss deeply these sensor types.

1. Active Infrared Sensor:    Active infrared sensors are the types of infrared sensor. The IR is emitted by an IR  light emitting diode and received by a photodiode or phototransistor cells. While in the process of detection (emission and receiving), the radiation is may be changed. This leads to varies the radiation in the receiver. This is used to generate the output with the help of electronic circuit.
    There are two types of active IR sensors, 
Break Beam Sensors:


     The above diagram showing the break beam sensor working, IR emitter and receiver placed in opposite direction. While in the operation, IR emitted continuously towards the receiver. Obviously, If the object is placing in between the emitter and receiver IR rays are might be interrupted. Ir emitter always emits the radiation depends on the receiving the receiver. If the object is fully placed, so the desired output is completely blocked.
Reflectance Sensor:

2.Passive Infrared Sensor:


The detected radiations are converted into an electrical charge, which is proportional to the detected level of the radiation. Then this charge is further improved by a built-in FET and fed to the output pin of the device which becomes applicable to an external circuit for further triggering and amplification of the alarm stages.The PIR sensor range is up to 10 meters at an angle of +15o or -15o.


These types of sensors use the reflective property of IR. The emitter emits an IR beam which is reflected by the object. The reflected IR is detected by the receiver. The object causes the change in the property of the reflected IR or the amount of IR received by the received by the receiver varies. The degree of change is dependent on the reflectance of the object.

Passive instruments detect natural energy that is reflected or emitted from the observed scene. passive instrument sense only radiation emitted by the object being viewed or reflected by the object from a source other than the instrument

The term PIR is the short form of the PassiveInfra Red. The term passive indicates that the sensor does not actively take part in the process, which means, it does not emit the referred IR signals itself, rather passively detects the infrared radiation coming from the surrounding area.

Comments

Post a Comment

Popular posts from this blog

General puprose registers in 8051.

Image
Well, in yesterday's podcast discussed on registers in 8051, two types of a register, general purpose registers are today's article all about. The general purpose registers are called as RAM memory in 8051. It has 128 bytes of memory for this general purpose registers. These general purpose registers are divided into 3 areas, those are  Banks. Bit addressable areas. scratchpad areas.                                     Let we discuss clearly, Banks    In this bank, 4 types of banks are there like  bank 0 bank 1 bank 2 bank 3 In each bank has 8 registers those are R0 to R7. All these general purpose registers are byte addressable registers. An image is shown in below for better understanding,                                     ...
Read more

TCON Special Function register.

Image
If a counter is programmed to be a timer, it will count the internal clock frequency of the 8051 oscillator 12d. As an example, if the crystal frequency 6 MHz, then the timer clock will have a frequency of 500kHz.   The timers may operate in any one of four modes that are determined by the mode bits. In that the timer control TCON it is a special function register. TCON:   Pin Description of TCON: Bit Symbol TCON Bit Function 7 TF1l Timer 1 Overflow flag. Set when timer rolls from all 1's to 0. Cleared when processor vectors to execute interrupt service routine located at program address 001Bh. 6 TR1l Timer 1 run control bit. Set to 1 by a program to enable the timer to count; cleared to 0 by the program to halt timer. 5 TF0 l Timer 0 Overflow flag. Set when timer rolls from all 1's to 0. Cleared when processor vectors to execute interrupt service routine located at program address 000Bh. 4 TR0l Timer 0 run control bit. Set to 1 by a program to ...
Read more

TMOD Special Function Register.

TMOD register As we know there are 2 timer registers in 8051. Timer 0 and timer 1. Both of these registers use the same register called TMOD to set various timer operation modes. TMOD is an 8-bit register, in which lower 4 bits are for Timer 0 and upper 4 bits are for Timer 1. See table below. MSB ---- LSB GATE C/T M1 M0 GATE C/T M1 M0 TIMER 1 TIMER 0 Bit Description: Bit TMOD Bit Function 7 Gate -- OR gate enable bit which controls RUN/STOP of timer 1. Set to 1 by the program to enable the timer to run if bit TR1 in TCON is set and the signal on external interrupt is high. Cleared to 0 by the program to enable time to run if bit TR1 is set. 6 C/ T  -- Set to 1 by the program to make timer 1 act as a counter by counting pulses from external input pins 3.5. Cleared to zero by the program to make timer act as a timer by counting internal frequency. 5 M1 -- Timer/counter operating mode select bit 1. Set/cleared by the...
Read more