Accelerometers are very exciting little things. When I say "little", I mean it, as they usuallyfits 4 or more on a finger nail! And each typically has some 7-20 points so solder. This makes them quite hard to work with, and so I recomend that you also buy a board of some sort, so that you end up with something that you can hook up to your Microcontroller easily.
What you get from the thing is a signal. The signal can be analouge, I2C, or anything else, depending on the thing you get.
I prefer analouge, it is just SO easy to work with; hook it up to an analoge input, read, you are go :)
So what does it return to your microcontrolelr, then?
Well, inside the tiny box is a liiitle chamber with a gas or something. And around this gas cloud or whatever, there are sensors. The gas is lighter or heavier than air or something (this is very precise info, no? ;) - and the resoult is that you get info about how the thing is tilted, or moved around in the air.
You can get them with 1, 2, or 3 axis, I have not seen them with 4 yet (joke).
You know them from the Ninendo Wii handles, and you can use them for such things as:
- Registering drift on fast robots
- Registering if the robot-pet-animal is lifted up, perhaps shaken by the stupid kid
- Cool "In Air" joysticks
- To build something that will tell you how fast your car is accelerating.. or your bike ;)
- Registering if your Sumo-robot is just getting hit by another
- Making auto-corecting flying things
- and much more :)
I got mine here:
I just stumpled upon this place that aprantly sells some nice ones:
- and have a nice background info: