New 'bot idea, need some input

[galannthegreat]

I am currently planning on developing a new 'bot. I want to make it along the lines of a micromouse style robot, using stepper motors as my drivetrain. I want to make it basic for starters (basic object avoidance). Then down the road I want to add to it to make it more advanced.

So, for starters I am toying with the idea of directly connecting a wheel the the shaft of the stepper or to use the gear that is on the motor to turn a geared wheel of some sort. What should I do?

Also I am trying to choose a driving method for the motor (it's unipolar btw), driver chip (good recommendation would be greatly appreciated), or premade board, or make a driver out of discrete components. Which route should I go?

Any input/ideas/recommendations would be nice.

Here is the motor I'm planning on using.
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=171601

[nottoooily]

So, for starters I am toying with the idea of directly connecting a wheel the the shaft of the stepper or to use the gear that is on the motor to turn a geared wheel of some sort. What should I do?

You need to find out what speed and torque you want. That'll determine if you need gearing. If you try to make a gearbox be prepared for some precision machining or you'll easily get teeth jumping, breaking off or binding.

[Pratheek]

From my experience bipolar stepper motors give better torque than unipolar steppers. I would suggest you use bipolar steppers.

For the driver you can use L293 or the L297/L298 ICs(L293 has less options, but it is cheaper and circuit is simpler than L297/L298).

[galannthegreat]

Thanks for the replies.

@ Pratheek

Thanks, I'll look around and find a substitute. I also have access to some nifty driving chips for bipolar steppers.

The nifty chip:http://www.allegromicro.com/en/Products/Part_Numbers/3988/3988.pdf (either design a board with the amazing tools at my disposal, or get some Easy Drivers from sparkfun)

Possible substitute:http://www.sparkfun.com/commerce/product_info.php?products_id=9238

@ nottoooily

If I do a gearing method I'll use a wheel with a gear on the wheel itself, or just use direct drive. The direct drive method will be the more likely choice now that I'm looking at bipolar motors.

If you have any places in mind that have wheels with gears directly on them I would be in great appreciation of that.

Here is the kind of wheel that I'm talking about: