Transmitting Data Through Laser

[MaltiK]

Is this possible to use a LDR on one microcontroller and a laser on another and when the laser hits the LDR 1's appear, and when it doesnt, 0's appear, does anyone know of a tutorial for this, its a very interesting subject.

[arixrobotics]

I've done a project like this some years ago. But I transmitted analog signals instead of digital 

It's pretty easy really. What I did before was I connect a laser pointer to the audio-out of a radio, and an LDR to the audio-in of an amplifier. I can't really remember the exact circuitry, but it was probably just some transistors for a bit of amplification etc.

This setting worked perfectly indoors. The furtherst I tested indoors was like 5 metres, and there was very little noise.

I tried to do it outdoors during a party we had, but the laser beam was too small to see from a few metres. I had a really hard time trying to focus the beam exactly on the LDR. Since a party is not a party without music, I had to cancel my experimentation after a few minutes of trying 

I remembered seeing some tutorials on the web. There was this guy who managed to get his system working across the street. But he used a really big laser.

Google around!


Found this: http://www.instructables.com/id/Send-Music-over-a-Laser-Beam/

[Half Shell]

Sweet project man. How long did it take you to write the interface for it (translating data to laser and then back to data again)?

[airman00]

there is no software involved with the laser music system , its all in the circuitry

[ArcMan]

When I was in high school, I saw a LASER data transmission project.  If you can imagine this, on the transmission side, the guy glued a piece of cardboard to a speaker cone on edge so that the cardboard stuck out perpendicular to the speaker cone.  The speaker/cardboard were positioned so that it blocked the LASER beam when the speaker coil was not energized and unblocked it when the speaker coil was energized.  He would send a "high-speed" data stream through the speaker.  The receiver on the other end would then reproduce the data stream.

[izua]

check these projects:
http://ronja.twibright.com/
http://www.modulatedlight.org/

they give a decent intro on the subject.

[Admin]

Its actually really easy . . . hook up the outputs/inputs to the Tx and Rx of your mcu UART, and you're done

If you have a $50 Robot completed and a pocket laser handy, I bet you can get it working in under 2 hours (including any soldering).

[MaltiK]

Its actually really easy . . . hook up the outputs/inputs to the Tx and Rx of your mcu UART, and you're done

If you have a $50 Robot completed and a pocket laser handy, I bet you can get it working in under 2 hours (including any soldering).

So, using the Laser as a transmitter, what do you use as a reciever, and LDR?

[Admin]

So, using the Laser as a transmitter, what do you use as a reciever, and LDR?

Depends on the wavelength of the laser

Unfortunately an LDR is too slow for a receiver, as it takes up to ~10 ms to change resistance. I *think* the pen lasers also emit infrared but not sure. Try using an infrared LED receiver and see if you get a signal - LEDs take only microseconds to detect a signal.