There are several functions I’d like to create that are dependent on the ability to track absolute direction. If we are able to track the direction that the robot is pointing, it will allow much more creative programming solution.
The problem you might run into is interference from the motors/wires/whatever. I believe a college team tried using a compass and the interference made if almost useless. I’m considering using one this year (yay no restrictions on sensors in college!) and just making sure it’s really far away from any electronics, but stuff like this is really hard to debug when you don’t realise having your motors running is throwing off your data.
I used a digital compass once and it doesn’t really point in known directions. It had to spin around get a reading and then from there you had directions. It really is not better then a gyro. You could argue gyros drift, but you are not going to get great reading from a compass either.
Luke - what you are describing is called a gyrometer. This can give you the absolute direction that the sensor is facing. HOWEVER due to the weak magnetic field of the earth, robots always being used indoors and a giant metal cage (aka the robot) around the sensor it will not return very accurate results.