Visible Light Communication


I am working on a project in which i wan to transmit data via LED and receive it via a Photodiode.
By far i am able to receive data by using OOK, bu he problem is that as i decrease the delay of blinking the LED the receiver goes out of sync and is not able to receive.
After reading a bit i found out that the flickering can be reduced so that human eye is not able to notice the flickering and a he same time data transmission is possible, by using PWM and Manchester Coding.

he problem is that i don't know how to code either of them. Any help?

Is there some reason not to use Infra Red?

IR serial communication Thread


I suggest using a 5v visible red laser diode module on the transmitter and it will help to align the photocell. The diode is available at BrainyBits for very cheap and less than 1mw

Google "arduino manchester" for code.

Please give more details about your project. What kind of data do you want to transmit, continuously or every now and then?

What modulation do you use? PWM is usable for continuous transmission of an analog value, but not for multiple or digital values.

How do you prevent ambient light from interfering with your signal?

IR transmission is in use with remote controls since a long time, you can use it instead of visible light, or use the same method with visible light, just as you like.

hi shivanksharma91,

do you have any solution regarding of the problem you mentioned?

I suspect the answer is no. shivanksharma91 was hoping to be given the solution on a silver plate and when this did not happen, lost interest in the idea. Sadly, this happens many times per day, every day, on this forum.

that's sad :frowning:

the solution to his problem was in post #1 & #3. Number 4 told him all he needed to make it work well.

do some reading and give it a try.

that's sad :frowning:

It is sad, but perhaps 1 in 20 new forum members will learn something and perhaps go on to help others in the future.