Principles and practices

My project is to build a mini two wheel remote control vehicle. It will have an arm on the bottom and an accelerometer. With a remote control that will have two joysticks. Each one will control one side. There also will be buttons to control the motion the arm. The arm will be able to extend out, rotate and close in order to pick objects up. The accelerometer will have its data brought into a formula which will calculate how fast the vehicle is going in miles per hour/kilometers per hour.