Hi Friends
I have tried to make this post as simple and less techinal as possible
Universal Remote controls are the latest trend. Nowadays it is no surprise to find 4 or 5 different remote control units in an average living room. TV, Stereo set, DVD player, VCR, AC,Settop box and a Satellite receiver are among the most popular devices and each and every one of them has a unique remote control unit. People want to control all these devices with one single universal remote control unit.
Types of Universal Remotes
Two major types of universal remote controllers exist: Learning controllers and Lookup Table controllers. A combination of both types in one controller is also possible.
Learning Universal Remote Controls
This type of universal remote controllers has the ability to learn new Device Infrared codes. Usually you must align it head to head with the original remote controller and then press a special sequence of buttons on both controllers. The universal remote controller sees the patterns transmitted by the original remote controller and stores them in its memory. Later it can play back the learned patterns when you press the keys on the universal remote controller.
One of the biggest advantages of this approach is that the universal remote controller can learn codes of brand new remote controllers as well as the old available remotes.
Look-Up Table based Universal Remote Controllers
A lookup table universal remote controller uses lookup tables to simulate the original controllers . In order to program the universal remote controller one needs to enter a special 3 or 4 digit code which can usually be found in a little booklet that came with the universal remote controller. This code internally represents a device/model/brand and all keys of the universal remote controller are mapped to their corresponding commands.
The major disadvantage of this sort of universal remote controllers is that devices which are younger than the universal remote controller are not supported by it, simply because the universal remote controller manufacturer cannot implement something which doesn't exist yet.
Device based Universal Remotes
Most universal remotes sold today are device based. When using this type of remote the user presses a button associated with the desired device to control and then uses the remaining buttons to control that single device. To start controlling another device the user presses a different device button and the remote then starts sending command to the new device. Typical mode buttons on this type of remote might be labeled "TV", "DVD", "Receiver", etc. An example of a device based remote is the Home Theater Master line of remotes.
Activity based Universal Remotes
Some universal remotes work on the concept of activities. Instead of the user controlling each device individually they instead focus on the 'activity' that they want to perform. For example they might want to 'Watch a Movie', 'Listen to Music', or 'Watch TV' When a particular activity is selected the universal remote may send out the necessary command to various devices to turn on and to configure device to accomplish the desired activity. For example selecting a 'Watch a movie' activity might turn on the TV, configure the TV to the DVD video input, turn on the amplifier, configure the amplifier to the DVD audio input, turn on the DVD player, and start the DVD playing. One of the most popular activity based remotes is the Logitech Harmony line of remotes.
Some advanced technologies are 2 way IR remotes,Home lightcontrol Universal remotes like ZWave/Zigbee etc
