Re: How is infrared communication used in the world today?

Dear Michelle, 
You and your partner are undertaking a project that certainly has a lot of 
history behind it.  For one thing, you should consider that infrared signals 
are actually just one form of electromagnetic radiation.  Of course, also in 
the category of electrocmagentic (EM) radiation are light and radio waves.  
Thus, what you are doing is actually building a "radio" that operates at 
infrared wavelengths!  You should also know that you probably have a 
technology right in your home that does something very similar - your TV 
remote control.  Most modern remotes work at infrared wavelengths, though 
some operate in the visible light and others in the radio frequency regions 
of the EM spectrum.  If you have an infrared remote, try this experiment:  
Have someone turn on a video camcorder.  Most are sensitive to short 
wavelength IR.  Then point the remote at the camcorder and "click" some 
buttons at various intervals.  Now look at the tape - you should see a light 
blinking on the remote for every time you "clicked" on a button.  
     Some computers today are equipped with infrared ports that allow 
wireless "docking" between computers or from a computer to another device 
(such as a Palm Pilot).  The most well known of these is the Mac iBook, but 
others are being produced with these, as well.  It is known as the AirPort 
(http://www.apple.com/airport).  I beleive that there are also some infrared 
or radio based sound transmitters that you can "hook" up to your TV/Stereo 
that beam the sound directly to a headset.  The idea is that a person can 
watch TV or listen to a stereo without having to disturb others in the room.  
Another similar technology that has recently appeared on the market is 
remote TV 
receivers.  These operate at radio frequencies, but the basic idea is the 
same.  You can hook the transmitter up to your satellite dish or DVD player 
and "beam" the signal to all the TVs in your house.  Coupled with that is a 
radio frequency remote that lets you change the channel!  A more high tech 
example is the use of infrared lasers to send signals from one satellite to 
another.  IR is less susceptable to jamming and so makes for very secure 
communications.  You should be aware that IR as a "radio" signal has 
limitations; specifically it cannot go through barriers (such as walls or 
clouds) very well.  This is why radio frequencies are better for that sort 
of thing.  Good luck with your project.  If you have any other questions, 
please feel free to email me at tjamison@observera.com
Regards,  Todd