What is the lowest implementation cost for my infrared comm?

[capfelix]

Hi,

I'm a newbie in infrared communication. I have a project here which involved bidirectional infrared communication (half-duplex type). I have a receiver which sit on top of a room ceiling and a handheld transmitter on the floor. Useful data byte transferred here is 8-bit long. The way both TX/RX works is that the transmitter will send a command to the receiver and the receiver will transmit back information to the transmitter. Usually the reply data doesn't go beyond 2-3 bytes long.

Transmission speed doesn't have to fast. Even <2.4kbit/s will do since the max command will transmit will be less than 10.

Distance here is 10-15 feet indoor with lighting exist. Does this need IrDA to work or simple IR should do the work? I'm looking for the lowest implementation cost solution here.

Pls advise.

Thanks in advance.

[Ttelmah]

Lowest implementation cost, probably a PIC, directly driving the source LED, with suitable current limiting resistor, generating tone bursts for the '0's. At the receiver, a NE567, or similar PLL, feeding into a PIC input. With careful choice of the data coding, this is relatively simple, and very cheap.
Easiest, while still reasonably priced, use an oscillator running at the transmit frequency (can even be a PWM output from the PIC), and 'gate' this signal with the serial stream. Advantage is that you can use standard serial driver code, instead of having to go 'DIY'. For the receiver, you can use the same PLL, or better, look at a IS1U60. More expensive, but has the receiver diode, and tone decoder all built into one package.
Repeat the data a couple of times in each direction, and add some error checking. You basically then have the system used for IR remote controls.

Best Wishes