IR serial Link ?

[nurquhar]

Is it possible to get a bidirectional IR serial link between two PIC systems

Is it as simple as hooking up an IR Reciever and Emiiter to the TX and RX pins of the PIC's ?

I looked at a Vishay TSOP 36kHz (TSOP1236) Reciever photodiode and it looks to have a simple binary output from its internal amplifier and band pass filter. I guess to make the emitter diode work I would need to modulate the TX signal at 36kHz also. Hopfully feeding the PIC's timer output along with the TX pin into an AND gate would do it

Has anyone done this before ? Is this the way to do it

I was hoping to get it to work at 1200 baud. I guess some CRC type of data packet check would be essential to detect data failures.

[FvM]

Reading the IR receiver dataheets thoroughly, you'll notice, that it isn't suited for the intended operation:

[nurquhar]

It looks like IrDA is the way to go. I found this reference project which uses two PIC to send messages to an LCD over a IR serial link.

http://avtanski.net/projects/lcd_serial/#DATA

[FvM]

The advantage of IrDA is in using a standardized protocol. Unfortunately it's not directly supported by 8-Bit PICs, so you have to use a software encoder/decoder as in the present project. Encoding of a datastream for transmission/reception by 36 or 38 kHz remote control equipment would involve a similar effort, I think, but may possibly achieve larger distances.

A PIC24F UART is supporting IrDA directly, by the way.

[nurquhar]

I found this encoder/decoder chip which looks like it simplifies the operation. It looks like one could just hookup the PIC's serial port directly to the chip and an IrDA part and get quite a fast IR serial link, ie upto 115.2 kBaud.

http://www.farnell.com/datasheets/71907.pdf