Infrared Beam Sensors

Infrared Sensors are the sensors that utilize Infrared waves to detect motion. Infrared sensors are used for various purposes but mainly they are used in security solutions installed at residential and commercial.

Infrared sensors are of two types i.e. Active Infrared Sensors and Passive Infrared Sensors. The Infrared beam sensors or Photobeam sensors are the ones that use Active Infrared (AIR) for detecting the motion and thus we are here with a complete guide on AIR sensors only.

Active Infrared Sensors: AIR sensors are the type of sensors that emit infrared waves through a transmitter which gets received by a receiver. Any alteration in the path of the waves indicates the detection of an object.

Components of Active Infrared Sensor:

• • Transmitter- The transmitter is equipped with an Infrared LED (Light Emitting Diode) which emits Infrared waves continuously in a straight line like a beam.

• • Transmission Medium- Infrared waves need a transmission medium to travel from one place to another. The medium can be vacuum, environment, fibre cables, etc. depending upon the product Infrared has been used in.

• • Receiver- The receiver of an Infrared sensor contains a photodiode which is sensitive to IR waves emitted by the Infrared LED and thus detects all the variations in received waves. 

Types of Active Infrared Sensors:

The Active Infrared Sensors are of two types:-

1. Break Beam Sensors- These are the sensors in which the transmitter and the receiver are placed in a straight line facing each other. The transmitter continuously keeps on sending the Infrared waves to the receiver and the receiver keeps a track of the amount being received.

2. Reflectance Sensors- These sensors work on the reflecting property of Infrared waves. The transmitter keeps on transmitting the waves continuously in a line which gets reflected by a fixed surface in front and sent to the receiver placed beside.

Types of Break Beam Photobeam Sensors :

1. Dual Beam Sensors – Dual beam Active Infrared (AIR) beam sensors are the ones that have two sources of infrared waves from a single transmitter that reach the receiver. Both the transmitted waves are captured by the receiver’s two sensors positioned in line with the transmitter.

2. Tripple Beam Sensors – Tripple beam Active Infrared (AIR) beam sensors work in a similar manner to dual beam sensors but they have three sources of beam and three sensors in the receiver to capture the transmitted waves.

3. Quad Beam Sensors – Quad beam Active Infrared (AIR) beam sensors work in a similar manner to dual and tripple beam sensors but they have four sources of beam and four sensors in the receiver to capture the transmitted waves.

How Infrared Beam Sensors work:

The beam sensors work in the following sequence:-

1. 1. The Infrared LED present inside the transmitter continuously emits IR waves in a straight line that travel through the transmission medium.
   2. The transmitted waves are received by the photodiode inside the receiver.
   3. Depending upon the sensor type, the receiver either receives the transmitted waves directly or after reflection from a fixed object in front.
   4. The received Infrared is further processed depending upon its intensity. The output of the IR receiver is generally small and amplifiers are used to amplify the signal so as to utilize the signal as per the requirement.
   5. If the beam is travelling to the receiver without any interruption, the security alarm system attached with the Photobeam sensors is at rest.
   6. Whenever someone comes in the path of the waves, the beam gets distorted and the amount of light reaching the receiver gets changed.
   7. The changed intensity is measured by the receiver and it considers the change as an attempt of intrusion thus sending a warning signal to the alarm system.
   8. The alarm system on receiving the warning signal gets activated and as per its programming reacts to the intrusion situation by giving a loud sound.

Applications of Infrared Beam Sensors:

• • Proximity Sensors: Active Infrared sensors are used as proximity sensors in mobile phones and robots to calculate the distance.

• • Products Detector: Beam sensors are used to detect the presence of products on a conveyor belt

• • Intrusion Detection System: Many security products are equipped with infrared beam sensors to detect intruders trying to enter a premises.

• • Automatic Doors: Infrared sensors identify a person coming close to the automatic doors and open without being touched.

• • Automated Lights: Automatic lights also work on the principle of Infrared waves by detecting the motion of the person in their range.

Advantages of Infrared Beam Sensors:

• • Infrared beam sensors detect the motion of objects both in light and dark with equal reliability.

• • The infrared sensors do not need any contact with the object to be detected.

• • The Infrared beam sensors are small in size.

• • The gadgets operating with Infrared sensors do not consume much battery making the gadgets last longer.

• • The infrared sensors have a quick response.

• • They are considered secure due to the point-to-point mode of communication.