Whether a TV remote or a AC Remote, We all are surrounded by Remotes from all directions. There are different remotes for all appliances. Ever wondered how they works? You are lying on your bed and TV channel changes just by pressing a click on remote. Let’s learn about IR Remotes.
The technology we use in Remotes, is very simple and very old Technology, also called IR, or Infrared. Almost every remote, or 90% remotes around us are IR based remotes. IR are electromagnetic light radiations with a wavelength greater than that of visible light and hence can not be seen by a human eye. Although, It can be seen using a camera. So, the next time you are sitting holding your remote, point it towards your phone camera and press any key to see IR light.
Different Binary Codes for Each Button !
There is a specific predefined binary code for each and every button we have on our remote. When we press a button, The transmitting IR LED on the top, blinks very rapidly, in fashion predefined as binary code. The IR Receiver placed in the appliance detects the blink of LED and converts to the binary code again and verifies if this belongs to this appliance or not. If found correct, the requested operation is performed.
Let’s take an instance, the binary code for power button in your remote in 11011100, so the LED will blink in a fashion where 1 stands for ON and 0 stands for OFF. The LED blinks so much rapidly, you can’t even notice by watching it in camera.
Why Can’t you use a TV Remote as Set-top box Remote?
Along with the signal, an authentication binary code, also known as Device Address also gets transmitted, with this code, the receiver verifies that the signal is coming out from its own remote. The authentication code is always same for all the keys in a specific remote.
Due to this difference in authentication code and different binary code of buttons, the remotes do not interrupts and you cannot use a remote of TV for controlling your Set top box. i.e. If you have five device in front of you, If you presses a button on remote of specific device, there will be no change in other devices because the authentication code or button function code mismatches and the device simply ignores it.
Two-Way IR Communication
Or How AC Remotes Work?
It is also possible to have two way communication with IR. On this same protocol, the AC Remote works. Actually, the IR Blaster LED and Receiver, both are placed on both the sides, on the Remote and on the Receiver as well.
After the data is sent be the remote with authentication code, the device does the job and returns some data back to the remote with the help of IR LED placed, which is captured by the IR Receiver placed on the remote. The code sent back to the remote also have some data.
i.e. If you lowers your AC Temperature from 26 to 25, Your remote will also show it 25, It is updated in the remote by the code sent by your AC to the Remote! This two way IR Communication can be seen widely in AC Remotes.
Other Applications of IR
Along with remotes, IR can be used in many other biological as well as technical applications. In the past of Data Transfer Technology, Cell phone even comes with IR to send and receive data. If you want to send data from a mobile to another mobile, you have to keep them holding at a fixed position and the exchange of binary data was done just by blinking the IR LED. Don’t you think it was cool than WiFi and Bluetooth!
Pros and Cons of IR Technology
- These are Cheap. You can buy a IR LED under 5 INR.
- Low Power Consumption. Makes the batteries in remotes lasts for Years.
- Small Setup. Setup size is very small. Handy and easy to install in small remotes.
- Invisible. Makes it more effective and do not spoils the fun in dark.
- Non-interfering. Unique blink patterns makes them do not interfere in functioning of other appliances.
- Low Range. The range of remotes can be very less. May limit within a room.
- Outdoor issues. Can’t work under sun’s radiations.
- Low Power LEDs. Makes it difficult sometimes to use remotes. You have to hold them straight in front.
Is Infrared Harmful for us?
The clear cut answer for this is No. IR light or radiations used in Remote controllers and other devices are not really harmful for humans and skin. But some studies show that IR can damage the lens and cornea of the Eye and thus staring at the sun is harmful or unintelligent. But, We are not going to put a remote controller in front of our eyes for a long time! However, The IR radiations from remote are very much less! Don’t forget it is very old technology and it never came to know that someone got this decease due to Remote or IR.
Some of the other technologies, we can use in the remote control are Radio Frequency and Bluetooth. Even if we see in 2020, Smart TVs are getting Bluetooth Remotes, Which makes them more convenient. i.e. You don’t need to hold the remote straight in front of TV. You can also communicate with TV with your Voice! Yes, even budget Android TVs are getting Google Assistant in them, which you can use by sending the Voice Commands using your Remote Controller!
Refer to Wikipedia for Infrared.