I am trying to plot the movement of an object in the screen. Using MPU 6050 breakout board with Arduino UNO R3. So far, I have converted raw accelerometer & gyro values to angle, filtered to account for gyro drift etc. So, essentially I have roll, pitch & yaw angle now.
How can I use those angles to find (x, y) points to be plotted?
The angles tell you the orientation (relative to the initial orientation), not the position. Unless you know that some point of the object is at a known position, you don't have enough information to know where any point of it is.
You cant know absolute position, but I would imagine you can calculate position with respect to the position your device was located when it was powered on.
Use the accelerometer to calculate velocities in x, y, z direction and keep track of the position with simple position = velocity * time. I havent done something like this, so it might be more difficult to implement, but this is how I would start.