I shall add this this project I'm working on to the hardware communications section once I get the documentation sorted out but in the mean time I have a small question concerning an equation.

I'm communicating with a Scribbler robot using the Serial library. The major hurdle in this is the fact that I can't send a byte array to the bot because PBASIC reads byte arrays as an ASCII string. Java uses unicode so this complicates things. I got around the problem by sending the information piecemeal a bit at a time. Like I said - I'll post the documentation so anyone else new to communicating with PBASIC can have a crack. (The instant joy - just add Processing - factor has been the highlight of my week, this robot is really easy for stupid people, no, really).

Anyhoo ->

I have a subroutine in the Scribbler hacked from the demo code for the robot. It takes speed for each wheel and a duration for movement.

In the demo, for 90 degrees left it uses:

motor_r = +50
motor_l = -50
move_time = 30

(Max speed of 100). So that works out as 3 degrees per move_time = 1 at speed = 50. Or PI/60 radians.

I'm trying to figure out the equation that spells out the relationship between degrees/radians, move_time and speed.

I'm not even close right now, could anyone offer any insights I'm hoping to build a class that will offer some precise control over the robot. (I'd build a library but I'm waiting for that page on Processing Hacks telling you how to build stuff in Eclipse to appear).

You might find this paper, an old favourite, useful if you're simulating/modelling two-wheeled robots:

A Tutorial and Elementary Trajectory Model for the Differential Steering System of Robot Wheel Actuators by G.W. Lucas