Hi guys.
I'm trying to send data to a large distance, something like 1Km and farther. i'm using a regular 650nm laser diode. the problem is that the beam is scattered and has low energy. Any ideas how I can maintain the angle of the beam so that it will be more focus?
can anyone suggest me a laser diode that suitable for those distances?
thanks alot.
KOOPI:
Hi guys.I'm trying to send data to a large distance, something like 1Km and farther. i'm using a regular 650nm laser diode. the problem is that the beam is scattered and has low energy. Any ideas how I can maintain the angle of the beam so that it will be more focus?
can anyone suggest me a laser diode that suitable for those distances?thanks alot.
High power green lasers are available on ebay.
Security side:
Be careful, a laser is very dangerous.
Check the laws in your country.
Technical side:
This principle has never been used in telecom, the radio beams have not been replaced by lasers beams.
In Telecom Laser are only used with optic fiber.
There is an explanation : the inability to focus a beam of light over long distances.
There is an explanation : the inability to focus a beam of light over long distances.
Well, that is a so-so reason. Lasers can be easily blocked by atmospheric conditions is probably a better reason.
This principle has never been used in telecom
Wrong.
Very wrong.
Not over such great distances, true, but over a few hundred metres, like between buildings, commercial systems are available, and have been since the 1970s.
Edit: spelling
KOOPI:
Hi guys.I'm trying to send data to a large distance, something like 1Km and farther. i'm using a regular 650nm laser diode. the problem is that the beam is scattered and has low energy. Any ideas how I can maintain the angle of the beam so that it will be more focus?
can anyone suggest me a laser diode that suitable for those distances?thanks alot.
That is usually done with external culminating optics, and with large optical lenses or focusing mirror at the receiving end. Inexpensive laser diodes just are not designed with high quality lenses suitable for more then a few tens of feet before the pattern becomes too wide. Alignment can be a bitch and wind caused vibrations mean steady mounting is required.
culminating optics,
sp."collimating"
AWOL:
culminating optics,
sp."collimating"
Good thing you knew what I meant, and didn't swallow your gum. 
Hello,
In my project i need to transfer data i.e text through laser beam . can someon can guide me please how do i start?
how i convert the text to binary and send it to the laser?
thanks!
Will this be one way? or two way? Very hard to do one way as there is no feedback as to if the data is received properly.
how i convert the text to binary and send it to the laser?
The text (if it is in a computer) already is in binary.
Which laser are you using?
Why not start simple/safe, and try sending data using cheaper, ready made IR components used for 38kHz remote control applications?
OP
In my project i need to transfer data i.e text through laser beam .
AWOL
Why not start simple/safe, and try sending data using cheaper, ready made IR components used for 38kHz remote control applications?
Because that's not what the OP wants to do.
@steinie44: lasers are dangerous things - I'm trying to save the OP's retinas (and those of innocent bystanders), and still give them an approach that can easily be extended to lasers when the basic principles are understood (38kHz modulation works for lasers too, BTDT)
The fact that they asked the question in a hobby forum suggests to me they are not expert users, and may be unaware of the potential dangers.
(I've worked with both lasers and IR illuminators - even the latter had eye-safe distances of many metres)
KOOPI:
Hello,In my project i need to transfer data i.e text through laser beam . can someon can guide me please how do i start?
how i convert the text to binary and send it to the laser?
This sounds like an academic project. How far have you got so far? I mean, can you send a laser beam? Can you modulate it? Can you detect it? Can you detect the modulation? Can you control the modulation using a TTL signal, and provide the detection as a TTL signal? All of this is fundamental to your solution but outside the scope of Arduino.
Once you have got to the point where you can put a TTL signal into one device and get a similar signal out of the remote device, I suppose you would just connect those signals to hardware UARTs to encode/decode a serial bit stream over the modulation. If you get that working then the rest of it seems trivial.