Scope & Limitation of Project

Basically, this project - Infrared Audio Headphone Link for TV is suitable to use by someone who having trouble to understand what’s being said on the TV. Different people have a different hearing difficulty. This project gives some other advantages to the other field of engineering such as, in medical electronics field, this product itself gives some advantages to patients. For an example, for those who just had an accident and it’s very difficult for them to control the volume of sounds that being produce by TV.

Scope of the project

Transmitter unit

 Small set-top box accepts line level audio (either mono or stereo) from a TV receiver, VCR or DVD player

 Input impedance : 47kohm

 PWM output via six infrared LEDs

 Range : about five meters

 Power supply : 12V AC or 15V to 18V DC, with an average current drain of approximately 25mA

Receiver unit

 A small portable box which responds to the modulated IR light beam from the transmitter demodulates the audio and drives a standard pair of stereo headphones (2 x 32ohm impedance).

 Power supply : four AA cells (either alkaline or rechargeable NiMH)

 Average current drain: approximately 20mA, giving a battery service life of 80 to 100 hours or more.

 Controls : local volume control and a power on/off switch, plus a power/ signal indicator LED

Limitations of the project

 Not more than 5 m

 Frequency range below to 20 kHz since human frequency range is from 20 Hz (cycles per second) up to 20 kHz (20,000 Hz)

 Provides a single channel audio link via infrared (IR) light.

 Overall frequency response restricted to 20 Hz to 12 KHz with a small amount of treble boost (maximum of 7dB at about 8 KHz

Conclusion:

By this way people can hear as loudly as they want without disturbing others. These types of headphones preferably good surround the ears muff-type headphones which not only delivers the wanted sounds directly to the ears and hearing aids but also cut back the competing sounds at the same time. The right kinds of headphones with some acoustic damping in the earmuffs will not cause the hearing aids to emit feedback and whistle sounds either.

The cordless headphone will became a better solution as it is not using any cord or wire. This headphone is being used either via a UHF or infrared link. It is using a transmitter or sender unit that sits on the top of the TV, plus a small battery-operated receiver to drive the headphones at the end.

This project limitation is, the receiver unit is built into the actual earphones or the headband, so it can’t be used with any other headphones.