accelerometer based digitel pen

hi,
i am doing accelerometer based digitel pen as my final project.That is what ever we write using digitel pen words should inserted to computer.i prefered ADXL345 Triple axis accelerometer,Arduino UNO Rev3 (Original) and nRF2401 as my project components.so is this good selection or anything better for this project............

and i want to know how to chage acceleration signal to its distance.........that means.....how to calculate accelerometer moving distance....and plot the distance cordinate..........

please help me :)realy very confused

That sounds like a really interesting project.

Not sure if you'll be able to get the required information without a gyro, but no matter - I seek to set you
on the path of converting the acceleration data into movement or displacement data.

Basically, when we move, we can calculate the distance travelled by multiplying the velocity with the time.
So, 10 meters/second for 10 seconds = 100 meters

Trouble is though, the sensor provides G values - or acceleration as compared to the magnitude of gravity.
So, you need to work out the speed at any one time before you can convert this to a distance. This involves (yet more)
physics.

There's a description of the relationships between the various quantities needed, here: Classical mechanics - Wikipedia

I saw a discussion that looked at integrating (calculus term) the acceleration values over time to give positional data.
From memory, it was in a discussion about DIY SegWay self-balancing, type robots. You'll probably find some joy
in that type of a setting/forum.

Good luck.