Tfdu6103

[George Sephton]

Tfdu6103 - IR Transceiver

Hi,
I was looking around at IR stuff and I need to create a bi directional IR interfact where one device won't confuse itself with where the IR data is coming from but I found this, TFDU6103 : http://www.vishay.com/ir-transceivers/list/product-81211/ It's an IR Transceiver but Im not sure how it works. Am I right in thinking if I point 2 at each other I can merely send 1 line of data: serout 1,N2400, ("DATA") and that could then the other end could use serin to get it then send it's own thing out?

Assuming I set it out like it says on P7 of the manual I could use these 2 scripts:

SEND:

Main:
high 0 ; Show we are sending Data
pause 250
serout 1,N2400, ("1") ;Send Data
low 0

goto Wait
Wait:
serin 0,N2400,b0
if b0 = "1" then found ;Show Data is returned
goto Wait

found:
high 1
pause 1000
low 1
goto Main

RECEIVE:

Main:
serin 0,N2400,b0
if b0 = "1" then found ;Show Data is returned
goto Main

found:
high 1
pause 1000
low 1
serout 1,N2400, ("1") ;Send Data Back
 goto Main

It will be used with a PICAXE 28X1 and a 20M to send data in both directions.

Thanks,
George S.

 

[Dippy]

Not sure what you really mean, but those IRDA modules aren't much more than IR LEDs (though I am corrected to say "IRED" by the Data Sheet) and IR photodiode with some controller and amplifier.

It'll probably work if you wire it correctly.

It doesn't do any modulation/demodulation (which in itself can help to reject DC ambient light, but slows the Data Rate).

But if you are expecting it to talk to another IRDA and 100% ignore all other infra red sources then no.

However, the very fact that they are very directional will make it less prone to interference.
In most cases; IR is IR.
Sorry, if I have wrong end of stick.
Give it a go.
It's only your money.

 

[George Sephton]

Fair enough I guess, I just wanted to use 2 of these as they are the same model so I assumed there must be some kind of thing built in to stop it confusing it with which IR signal was sent, but otherwise you see no reason for it not to work?

 

[Dippy]

On the face of it I can't see any reasons not to work. But I've only ever done IRDA things with IRDA projects.

Reading the Data Sheet may save you problems, especially when I see things such as
"An on-chip protection circuit disables the LED driver if the TXD pin is asserted for longer than 100 μs."
I can just see problems where people do this then wonder why it doesn't work.
Asserted means switched on in this case btw.

You must remember that common-or-garden IR is the carrier. And in cheap electronics it is a very wide band. So, someone with a big IR flashy thing could interfere with you.

But, like I say, IRDA is fairly narrow angle. This naturally will cut down interference a bit.
Depends on application. No magic I'm afraid

 

[Dippy]

Rethink:
Actually, I think you are going to have problems at that slow baud rate if it does shutdown with 100microsecond assertion.
Just think how long it will be on at 2400.

Remember: these things are (usually) used with modulation/demodulation.

 

[George Sephton]

I guess I'd be sending single ascii characters at a time, assuming a small pause between each would restart the shutdown timer on the module.

 

[Dippy]

You could probably make a mod/dem circuit, but is it worth it?
Is there another technique you could use?