Phase Three are the build weeks. 

Building from scratch is very hard the first time. I chose to have a group project where they could all build the same thing. I decided on some simple RC pusher bots.  I also decide it would be neat to add some Lego blocks so the kids could individualize their robots.  

We started by taking some cheap RC race cars apart.  The cars had a simple all or nothing h-bridge circuit that powered both steering and the motor.  The cars supplied 3.1 volts to both the motor on the front wheel steering motor and on the drive motor.  The motors had two different windings so that the front motor would  not tear the front end out.  

I purchased a dual motor transmission system for ant weight battle bots with matched motors.

  We geared this down to 50:1 so there would be lots of power to push the other tanks around. The gear motor is able to do two gearings one is 58 to 1 and the other 204 to 1.  I found the 204 to 1 was to slow for the combat.  It had much more power at 204 but I found its tearing the center out my wheels to be a real down side to that gear ratio.  

I bought some steel plates from Home Depot to mount everything on.  These plates were pre-drilled with holes that matched the gear motors so they were perfect.

We cut up some plexiglass cutting boards to make the wedge and mounted the Battery at the rear to offset the weight and make it balance on the two wheels.  We then balanced them by gluing metal nuts to the front until the front just skimmed the table.

We placed to tables with the legs collapsed on the ground.  It was simple push combat last one on the table wins.  Since we only had two frequencies we had two teams red and blue.  The player who had the most wins for each team was the winner.   

It was a challenge and took many weeks to build the bots. Our youngest two were not able to finish their bots before the school year was up.  I hope to have a chance next year to do this project again with a new group of students.