I found one for the TI-84 called "Navigate" on TICalc.org, but it
crashes when I run it.
Any other suggestions, especially for the TI-80 as these are now a
dime a dozen :)
I don't know, but there is an open source program for phones with Java
ME that's called Compass: <http://www.getjar.com/mobile/1155/compass/>
or <http://www.qcontinuum.org/compass/>. It could probably be translated
into TI-Basic.
The TI-80's doesn't have any linking AFAIK. Do you plan to enter this
program by hand into each TI-80 or will you construct a robot to type it in?
Please report back if you find anything suitable since I would also be
interested in this.