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/computers/laser/free_space_laser_data_transmitter.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]

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/computers/laser/free_space_laser_data_transmitter.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

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/astronomy/nasa-beams-mona-lisa-to-moon-130118.htm

 

[dlgoff]

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...?

From the story link,

"This is the first time anyone has achieved one-way laser communication at planetary distances," David Smith, a researcher working with the LRO's Lunar Orbiter Laser Altimeter -- which received the Mona Lisa message -- said in a statement. "In the near future, this type of simple laser communication might serve as a backup for the radio communication that satellites use. In the more distance future, it may allow communication at higher data rates than present radio links can provide."

The team divided the famous da Vinci painting into sections measuring 150 by 200 pixels and then transmitted them via the pulsing of the laser to the orbiter at a data rate of about 300 bits per second.

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

FEC gives the receiver the ability to correct errors without needing a reverse channel to request retransmission of data, ...

 

[paulhunn]

Ok well I've found a pretty good amount of info online and i think a good approach 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.