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sswcharlie
- 21st September 2008, 20:59
Hi

Are there any circuits and code for communication between pic with bidirectional leds.

hey have been touted as a replacement for rfid. All I want is to get a unique code back to the master/reader pic and/or my PC.

Thanks

Charlie
skimask
- 22nd September 2008, 01:59
Hi
Are there any circuits and code for communication between pic with bidirectional leds.
hey have been touted as a replacement for rfid. All I want is to get a unique code back to the master/reader pic and/or my PC.
Thanks
Charlie

A bidirectional LED is generally regarded as 2 LEDs (usually a RED and a GREEN LED)
in the same package, with the polarities reversed, thereby you put current across the LED in one direction, it lights up RED, reverse the current and the LED lights up GREEN.

I don't see how these would be a replacement for RFID in any way....unless I'm stuck in the past or something...
Dave
- 22nd September 2008, 11:51
sswcharlie, You are probably thinking about something like the IrDA devices used in PDA'a and printers to transfer data....

Dave Purola,
N8NTA
sswcharlie
- 22nd September 2008, 20:47
Hi

This is what I was basing my request on. Theory has been around for a while, and there are circuits here to make it work.

Charlie
sswcharlie
- 22nd September 2008, 20:50
Well, how about here:

http://www.merl.com/papers/docs/TR2003-35.pdf

Charlie
mackrackit
- 22nd September 2008, 22:56
Like your article said, only good for a few centimeters. And I do not think it would be very reliable.

Look at this if you want IR communications.
http://rentron.com/PicBasic/IR_Chips.htm

Or are you wanting to build you own opto coupler? For that all you need is a photo transistor and an LED (maybe a resistor or two) and then you can send pulses.