IR LED(Infrared LED) | Code | Circuit | Pin configuration

 IR SENSOR | IR-LED

IR sensor is an electronic component.IR sensors are mainly used in money counting machines, IR cameras, security alarms, obstacle detection. A single IR sensor consists of transmitter and receiver part, they look like a LED types. So we can say that these are IR LEDs one is IR transmitter LED and the other is IR receiver LED as shown below.

Other names: Photo Diode, Optoelectronic component, IR-LED, IR-Transmitter, IR-Receiver, IR-Pair, IR-Module, IR proximity sensor.

Other related devices: IR module, TSOP1738, HSDL-4260, SIR204C.

 

IR-LED-PAIR

Features

• High reliability
• High radiant intensity
• Peak wavelength λp=875nm
• 2.54mm Lead spacing
• Low forward voltage
• Pb Free
• High power AlGaAs technology
• High speed: 40ns rise time

 

Technical specifications

• Forward current: 100mA
• Peak forward current: 500mA
• Forward voltage:1.9V
• Peak wave length:875nm

 

 

Pin Configuration

IR LED either transmitter or receiver has two terminals, the long one acts as anode and the shot one acts as a cathode terminal as shown in the above figure.

How to identify the IR LED

The pair of IR LEDs is called an IR sensor. The pair of IR LEDs have specific color indications as follows.

 

S.no	IR Transmitter LED	IR Receiver LED
Pair-1	White	Black
Pair-2	White	Blue
Pair-3	Blue	Black

 

In the pair-1 we have two IR LEDs transmitter is available in White color, Receiver is available in Black color, in pair-2 IR transmitter, is available in White color, Receiver is available in Blue color and in pair-3 IR transmitter is available in Blue color, Receiver is available in Black color.

NOTE: Don’t mix any two pairs of IR LEDs either transmitter or receiver.IR sensor must have an IR transmitter and Receiver LEDs.

Error case: we can say that from pair-2 white color LED acts as a Transmitter and Blue color LED acts as a Receiver. So in my case by mistake, if I took the  white color IR-LED from pair-2 and Blue color IR-LED from pair-3, so it leads to error case why because these two IR-LEDs acts as a transmitter part.     

Precaution: Don’t buy a single IR-LED either transmitter or receiver, buy a complete pair of IR-LED

How IR sensors are work

IR sensors works depend on the light principle-Infrared the light that means IR sensors respond only to the wavelength of  750nm-50um.

IR sensor has transmitter and receiver part. IR  transmitter emits the IR light, IR receiver responds only when this IR light will fall on the receiver.

For example, in my case I have taken the default  sensor output voltage will be LOGIC-1, if any IR light falls on the Receiver LED the output will change to LOGIC-0.

 

Modeling of IR Sensor

IR sensors working principle is the same as discussed above , here we have checked the position arrangement of IR LEDs.

1.IR LEDs are arranged face to face

2.IR LEDs are arranged side by side.

 

Case 1: IR LEDs are arranged face to face

IR-SENSOR-CIRCUIT

In this circuit default(IR light falls on the Receiver) the output is LOGIC-0 when  no  IR Light falls on the receiver the output will transition to LOGIC-1.

Note: IR LEDs are should be in Line of sight

Default

IR light falls on the Receiver

The output is LOGIC-0

Obstacle presence

IR light between the transmitter LED and IR Receiver LED will be cut by any Obstacle

The output is LOGIC-1.

 

Case 2: IR LEDs are arranged Side by Side

IR-SENSOR-CIRCUIT

In this circuit default (No IR light falls on the Receiver--No obstacle) the output is LOGIC-1 when IR Light falls on the receiver the output will transition to LOGIC-0.

 

Default

when there is  no obstacle in front of  IR LED, No IR light falls on the Receiver

The output is LOGIC-1

Obstacle presence

Here obstacle is present in front of the two IR LEDs then the IR light will reflects and falls on the Receiver LED.

The output is LOGIC-0.

Note: The object should have white color, then you can get efficient output because  white-color is perfectly reflect the IR-signal (The object should have an IR signal reflecting nature)

 

Applications

• Optoelectronic switch
• Infrared applied system
• Smoke detector
• Infrared cameras
• IR-Securit 

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