Saturday, April 17, 2010

MARVIN Porting

Yes, I am still working on MARVIN.  It's slow right now because of the nice weather we are experiencing, but I am still going.

Right now the motor count is at 27 and the sensor count is at 35.  I don't have enough ports for all the sensors, but I am mounting them anyway.  That way in the future I will be able to just switch sensors if I want to do something different.  They are useless sitting in my Lego drawers anyway.

I am actually using more PF motors than servo motors.  I have come up with some creative ways to control them with little or no feedback.  I mostly use them when I can say "turn the motor on for 0.5 seconds, and then reverse it for 0.5 seconds."  Or sometimes I attach a clutch gear and run the motor until I know the clutch gear will spin, and then reverse it.  The drive wheels are XL PF motors and I run them by time or by using the compass.  The bot is extremely heavy and I am glad I built the base frame ultra heavy duty.  I think I am going to use two XL PF motors on each drive wheel.  I built the drive train to accept up to three motors on each wheel.

Control of all the motors and sensors must be preplanned.  Below is an Excel spreadsheet I have been tweeking to get the best result.

Now that I know where all the elements are going, I have to wire the darned thing.  I have a feeling this is going to get messy.

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