Transmission of a computer image via a laser

paulhunn

Recently in the news NASA has transmitted an image of the Mona Lisa via a laser beam and i was wondering about some of the theory behind how they did it and maybe trying to recreate something similar on a (much) smaller scale.
I've seen some articles online that show a method for transmitting simple data like text via a serial port on a computer like this one: http://sci-toys.com/scitoys/scitoys/...ansmitter.html

Could this be modified in any way to transmit an image file? Possibly by directing the laser to a photo-diode connected to another computer via the serial port. I'm not sure if there's already any software which would fit the purpose or if i'd have to get something coded myself to do the job. I have very little programming experience so if anyone has in help in that respect i'd be really grateful.

If anyone has any help/info/advice or other suggestions they would be greatly appreciated

Thanks in advance

Paul

berkeman

Do you have a link to the NASA story? Transmitting digital data via laser/fiberoptics is nothing new. I'm wondering if they used some sort of mechanical scanning mirrors to pick up and then re-display the image...?

paulhunn

Yep the story is here: http://news.discovery.com/space/astr...oon-130118.htm

dlgoff

From the story link,

300 Bd?
I'm guessing they are using some sort of forward error correction (FEC) method.

paulhunn

Ok well i've found a pretty good amount of info online and i think a good aproach would would be to use an Arduino as an interface for the laser and receiver. Does anyone have any experience in using/coding one of these?

f95toli

The easiest way to experiment is to connect two computers via a null model cable, but where the "cable" is just an optical link. You don't need to use special software, a standard terminal program works just fine.

Hardware-wise all you need to do is to connect a laser diodes to the Tx pin, and photodiodes to the Rx pin of serial ports. The only potential problem is that you need to keep an eye on the voltage levels (the serial port works with +15V, so you need in interface chip or a voltage divider) and make sure you can supply enough current to the laser diode.

This kind of experiment is quite often done at school, I think I did it a couple of times.

You could of course use an Arduino, but I unless you are going to implement some fancy error correction that can't be done by the software on the computer I don't see the point.