Visible Light Communication

by rxwontfit
Tags: communication, ftdi, led, light, serial
rxwontfit is offline
Oct31-10, 05:33 PM
P: 13
A colleague and I are in our 4th year of Electrical Engineering and are designing a Visible Light Communication device capable of sending text, pictures, videos, etc over a binary light channel. We are currently using an FTDI chip to interface between the USB and receiver/transmitter. According the FTDI specs, the device is capable of Rx and Tx rates up to 3 MegaBaud. Assuming we have LEDs and Photodiodes (transmitters and receivers) capable of this frequency response - Does anybody have any recommendations from a Software perspective of what we could use to push data out the usb port? All coding examples I have come across in C++, PHP, and Mathematica cap at ~115,000 Baud. Any help, or serial class references are appreciated.

Thanks for your time and have a great day.
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NobodySpecial is offline
Oct31-10, 05:38 PM
P: 474
The FTDI chip comes with a driver to make it look like a serial port - if it doesn't google for "virtual com port"
A serial port is pretty easy to talk to in any language
rxwontfit is offline
Oct31-10, 05:56 PM
P: 13
indeed it does mask the usb as a serial port - but from a software side, communicating with the serial port requires that I fit within serial port restraints (within 115,000 baud?)... how can I transfer data at 3Mbaud if the software won't support it?

rxwontfit is offline
Oct31-10, 05:58 PM
P: 13

Visible Light Communication

it comes down to this: how do I send a 3Mbaud bitstream out of the USB port? I have the drivers installed for the FTDI chip, I'm looking for a language where I can actually specify that 3Mbaud is the baudrate...but from what I've seen I cannot find any.
MATLABdude is offline
Nov1-10, 12:53 AM
Sci Advisor
P: 1,724
It's not, but there's a say of hacking the driver so that you can get this transfer rate--some students I TA'd did this a few years back to facilitate higher speed transfers. You probably need to contact FTDI for more details.

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