IR Transmitter / Programming Project

In a programming class of mine we have 5 weeks or so to come up with a little program that does something unique with any language of our choosing. Other groups are allowing for the input of musical notes and such where the prgram will parse the notes and output the correct series of sounds to play whatever it is you entered. Another group is going to be working on making HTML an actual language instead of just a markup language. Our group decided to incorporate some hardware and are going to attempt to create a program that runs an IR transmitter. The user will be prompted to enter in a line of text and the IR transmitter will them output that text in morse code. Yes at first it seems rather pointless to use an IR transmitter instead of a regular LED but it would be so much cooler to transmit the text in “invisible” light which could only be detected by some sort of night vision system or a camcorder.

My questions are as follows. Has anyone had any experience building a cheap serial/paralle/usb IR transmitter? Would it be cheaper or easier just to pick one up online? Once we build it or buy it would we be able to use something like girder to implement our morse code translation program?

All in all the morse code translation doesn’t seem as if it could take too long to work out. Our biggest problem is just getting the hardware/software to work together and allow us to control the transmitter to output valid mores code. If you have any questions I’ll answer them ASAP. Other than that, that’s pretty much the situation if you have any comments or suggestions. Thanks in advance!

This link is a site dedicated to electronics for model railroaders. there are lots of IR circuits for things like detecting trains, and you should be able to modify one to provide the hardware for your project.

You should be able to put an IRED on a line from a PC’s parallel port, and have a homemade receiver beep or flash a light in response. That would be simple…

USB is likely to be a pain in the ass, but using a serial or parallel port should be a piece of cake. I’d go with a serial port because they’re supposed to be a little more robust when it comes to things like wiring mistakes (I’m pretty sure the RS-232C spec says they’re supposed to gracefully handle short circuits, for example, whereas a parallel port might be partially or totally damaged). Connect an LED through an appropriate resistor to the DTR or RTS line on a serial port and you should be able to programmatically toggle it on and off very easily.

Heck, if you have a laptop or PDA with a built-in IR port you might be able to figure out how to use it to do what you want to do without having to build any hardware at all. That would probably require more low-level access to the hardware than the operating system is likely to easily provide, though. You’d probably have to do more software hacking in that case.

For a class in college we had to design and build a simple wire-wrapped computer, write a simple monitor program (read memory, write memory, go to a location) and then make the computer do something. We (my partner and I) did the text --> Morse code thing, tho we did it to a speaker. we used one of the serial ports on the UART (the other was used to interface to the outside world).
We just sent hex 55 at 2400 baud (so it was 1200hz tone) for either a short or a long period. (note: we used the TTY (0-5 v) from the chip, not the +/- 12v of RS-232)

I’ve seen plenty of parallel port interface articles in ham radio magazines.

A quick google search reveals this:
http://www.lvr.com/parport.htm

that should get you started.

Brian