Research & Development Electronics Electrical

There’s something rather futuristic about talking ‘over’ a laser beam, which is what this inexpensive project allows. It will easily give a communication distance of several hundred metres, and with a parabolic light reflector, up to several kilometres. It transmits high quality audio and the link is virtually impossible for anyone else to tap into.

 

So clearly, this project is ideal for setting up a speech channel between two areas, say adjacent houses, or offices on opposite sides of the street. Or you could use it as a link between the work shop and the house. For duplex (two way) communication, you’ll obviously need two laser ‘channels’.

An important feature of transmission by laser beam is privacy. Because a laser beam is intentionally narrow, it’s virtually impossible for someone to tap into the link without you knowing. If someone intercepts the beam, the link is broken, signalling the interception. Fibre-optic cables also have high security, as it’s very difficult to splice into the cable without breaking the link. However it’s theoretically possible; so for the highest security, you probably can’t beat a line-of-sight laser beam.

You can also use an infrared laser. While this gives even better security, as you can’t see the laser beam without special IR sensitive equipment, it also makes alignment more difficult.

Main component of this project is laser diode. A laser diode needs a certain value of current, called the threshold current, before it emits laser light. A further increase in this current produces a greater light output. The relationship between output power and current in a laser diode is very linear, once the current is above the threshold, giving a low distortion when the beam is amplitude modulated. For example, the 65Onm 5mW laser diode used in this project has a typical threshold current of 3OmA and produces its full output when the current is raised by approximately 1OmA above the threshold to 4OmA. Further increasing the current will greatly reduce the life of the laser diode, and exceeding the absolute maximum of 8OmA will destroy it instantly. Laser diodes are very fragile and will not survive electrostatic discharges and momentary surges!

 

 

In this  project we transmit two type of data from the circuit. One is analogue data and second is dtmf data . In the analogue data we transfer the data from the mike and this sound is transmit through the laser and then  receive on the speaker at the other side.

 

In dtmf mode we use one 12 key  as a input keyboard in the circuit and when we press any number then this data is available on the other end and display on the  seven segment display.

 

In addition of these two signal we also applied a  signal from the mobile phone and we follow the same process of transfer the data  in the from of sound and  numeric data from the keypad of the mobile phone.

 

Transformer 9v 500mA

LASER he-Ne 5mm

IC74154

IC4049

IC7447

Seven segment display

Ic 741

IC 7805

Diode

IC 91214

Ic8870

Optical fiber

Resistances- 10k,1k,4.7k,220k

Capacitors- 0.1microfarad,00.1 microfarad,1000µf,470µf

Cupper clad board

Software Required:-

Window os

OrCAD

MS word

 

Applications:-

 

Ø            Networking between Computers.

Ø            Data downloading from PC to Mobile & vice versa

Ø            Communication between Buildings

Ø            For Security purposes- To protect house or lockers

Ø            For Military equipments- To find the target

Ø            For Medical machines- treatment of stone problem

Ø            For lightening purpose in sky

Ø            For Cutting of Glass or hard sheets

Ø            For controlling devices – Switch on/off

Ø            For Remote purpose