Arduino Robot for lowest cost

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It all started with this:
 Arduino Robot Challenge: How inexpensively can you create a robot using an Arduino for 5th Graders?

 I hope that this instructable has a certain elegance to its simpleness and will convince you to build your own and get some kids excited about technology with it!
Video of robot in Action!
 
Video -  Beta version:  improved front swivel (works on various floors better) and ENTER the pug named Mabel!

NEW - Wixel version in wall following mode!
 

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Step 1 Whats needed....

The lightbulb moment in this project was when I realized that I could use the DC motors within the K'nex Flash Robo Battlers for my robot drives.

- K'nex are familiar to kids. 
- They are inexpensive and readily available at the big box retailers (no shipping charges).
- The motor comes with a clutch and is a very durable and kid safe module to build a robot around.

So the BOM:

- 2 K'nex Flash Robo Battlers, $10 each at Walmart, Target, etc.
- Arduino Uno, approximately $30 at the MakerShed.
- Breadboard, switch for collision detection and jumpers from Radio Shack, less than $20.
- BOM from the H-bridge driver project at ITP. (the H-bridge driver chip cost about $3 plus shipping...wish I could have found this close by)

Comments

[sholtob]

you could have used a smaller arduino like the sparkfun pro mini or an arduino nano, they are bothe quite alot cheaper than the uno

[doncrush]

Good point. I am a newbie and trying to minimize any potential issues since we are working with 5th graders that do stuff like incessantly push the reset button while you are running demos...glad that my teaching partner noticed that, I thought I was losing my mind!

[sholtob]

the uno is also easier as you dont need to solder headers on if you want to reuse it, but the title is a little misleading

[doncrush]

Video thanks to Wendy!

[asd32gfg5]

Can you please give more details about your circuit in step 4? You give detailed instructions on how to open up the knex motor and then completely skip over the arduino circuit...lol :)

[doncrush]

Updated PDF (outputs re-arranged)

[doncrush]

http://itp.nyu.edu/physcomp/Labs/DCMotorControl

Can you tell I am a mechanical engineer?  And a total slackhacker when it comes to circuits.  The link above helped me figure it out.  Take a look at this page and see if you get it figured out.  If not let me know.

Thanks for asking!

[doncrush]

Note: school hallways are really dusty...these wheels did not get good enough traction to turn...weekend project!