> Now: how does the hero know which direction the front wheel is pointed?
> I see an encoder wheel that indicates how fast the wheel is turning, but
> nothing that says which direction the steering motor has the thing
> pointed. Is there some feedback mechanism that I'm missing? Or on
> startup is it supposed to calibrate itself somehow?
>
> Thanks for any info.
>
> Cheers,
>
> Mike Harm


Both the Head and the steering use a stepper motor with 6 wires. When you initialize a HERO 1 by typing 31 on the keypad the robot will turn the drive and head all the way to one side until it makes a contact with the limit switch. From here it knows how many steps to turn the motor back until it is straight ahead. On a stock HERO 1 in order to adjust the centering on the head and steering you have to adjust the springs at the limits so they contact at a different step.

It still has the problem of being an open loop system (except for the extreme limits) and if the wheel or head is turned a few steps in either direction the computer has know way of knowing about it. I had once read an article where an owner
added a limit switch at the exact center location. It was wired up to the expansion board on the head and could be checked that way. You might want to try something similar with your own encoder or opto's......

Robert