KINDS REMOTE CONTROL.
INTRODUCTION .
Wireless remote controls are control devices that allow you to activate certain functions on a device without having to physically activate the device yourself or having a cable connected to it. The wireless remote controls allow you to perform these functions from a distance away with a battery operated device and not with any cables. The wireless remote control systems can be used for many different purposes. You can find wireless remote control for lamp switches, wireless remote controls for winch and wireless remote control for iPods. The wireless remote control for iPods allows you to run the controls on the iPods from a distance away. These wireless controls allow you change songs, rewind or fast forward without having to be right next to the iPod.
HISTORY
The first remote intended to control a television was developed by Zenith Radio Corporation in 1950. The remote — officially called "Lazy Bones" was connected to the television set by a wire. To improve the cumbersome setup, a wireless remote control called "Flashmatic" was developed in 1955 which worked by shining a beam of light onto a photoelectric cell. Unfortunately, the cells did not distinguish between light from the remote and light from other sources and the Flashmatic also required that the remote control be pointed very accurately at the receiver.
In 1956 Robert Adler developed "Zenith Space Command", a wireless remote. It was mechanical and used ultrasound to change the channel and volume. When the user pushed a button on the remote control it clicked and struck a bar, hence the term "clicker". Each bar emitted a different frequency and circuits in the television detected this noise. The invention of the transistor made possible cheaper electronic remotes that contained a piezoelectric crystal that was fed by an oscillating electric current at a frequency near or above the upper threshold of human hearing, though still audible to dogs. The receiver contained a microphone attached to a circuit that was tuned to the same frequency. Some problems with this method were that the receiver could be triggered accidentally by naturally occurring noises, and some people, especially young women, could hear the piercing ultrasonic signals. There was even a noted incident in which a toy xylophone changed the channels on these types of TVs since some of the overtones from the xylophone matched the remote's ultrasonic frequency.
Jerrold remote control by General Instrument from the late 1970s
The impetus for a more complex type of television remote control came in the late 1970s with the development of the Ceefax teletext service by the BBC. Most commercial remote controls at that time had a limited number of functions, sometimes as few as three: next channel, previous channel, and volume/off. This type of control did not meet the needs of teletext sets where pages were identified with three-digit numbers. A remote control to select teletext pages would need buttons for each number from zero to nine, as well as other control functions, such as switching from text to picture, and the normal television controls of volume, station, brightness, colour intensity and so on. Early teletext sets used wired remote controls to select pages but the continuous use of the remote control required for teletext quickly indicated the need for a wireless device. So BBC engineers began talks with one or two television manufacturers which led to early prototypes in around 1977-78 that could control a much larger number of functions. ITT was one of the companies and later gave its name to the ITT protocol of infrared communication.
If you are like most Americans, you probably pick up a TV remote control at least once or twice a day. Let's look inside and see how they work. Here is the remote we will be dissecting today:
The remote control's job is to wait for you to press a key, and then to translate that key-press into infrared (pronounced "infra-red") light signals that are received by the TV. When you take off the back cover of the control you can see that there is really just 1 part visible: a printed circuit board that contains the electronics and the battery contacts .
The components that you see here are typical for most remotes. You can see an integrated circuit (also known as a chip) labeled "TA11835". The chip is packaged in what is known as an 18 pin Dual Inline Package, or a DIP. To the right of the chip you can see a diode, a transistor (black, with three leads), a resonator (yellow), two resistors (green) and a capacitor (dark blue). Next to the battery contacts there is a resistor (green) and a capacitor (tan disk). In this circuit, the chip can detect when a key is pressed. It then translates the key into a sequence something like morse code, with a different sequence for each different key. The chip sends that signal out to the transistor to amplify the signal and make it stronger.
Wave the TV remote control goodbye and change channel with a thumbs-up.
Not only will it be a godsend for lazy viewers, it could also save hours of fruitless scrabbling among the sofa in search of the remote control.
The all-seeing wave controller is the brainchild of Australian engineers Dr Prashan Premaratne and Quang Nguyen.
They believe it could be on sale within three years, ending the frustration involved in finding and using remote controls.
Dr Premaratne, of the University of Wollongong, said: "We all rely on remote controls to manage an increasing number of items including TVs, set-top boxes, DVDs and hi-fis, and the range of goods will continue to increase.
"Apart from the frustration of sometimes mislaying the remote control just when you need it, they do tend to have different sets of commands which have to be mastered.
"People have tried to replace remote controls with voice recognition or glove-based devices but with mixed results."
The device is designed to sit on a shelf or table which has a clear line of sight to the television and the owner.
Its software recognises simple, deliberate hand gestures and then sends the appropriate signal to a universal remote control, designed to work with most makes of television, video recorder, DVD player, hi-fi and digital set-top box.
In tests, published in the Institution of Engineering and Technology's Computer Vision Research Journal, a prototype worked in all kinds of lighting, and at a range of distances.
It was able to switch equipment on and off, alter the volume, change channels, play and stop. Dr Premaratne says anyone can learn the gestures within five minutes.
One is used to tell the device which item you want to switch on or adjust.
A clenched fist means "start", an outstretched hand with closed fingers means "power on", a thumbs-up sign means "up" and a sideways victory sign means "channel".
Crucially for anyone with small children, pets or gesticulating family members, the software can distinguish between real commands and unintentional gestures. The team has started work on making the gadget small enough to be built in to televisions or other devices.
They also want to adapt it for use with computer games consoles. Dr Premaratne said: "Normal game consoles rely on pressing series of buttons to get commands.
"Hand gestures can replace those button presses and the gaming experience will be truly revolutionized."
EXAMPLES OF REMOTE CONTROLS.
1 comment:
Most important for tv repair! Keep going on
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