Introduction: Foam Battle Robot

Materials list:

-Foam core

-Three continuous servo motors, two large and one small one

-One receiver

-One battery back for four AA or AAA batteries

-Two wheels, we used 3.2” Lego robotics wheels

-Mounting plates for the servos and screws

-Small piece of metal for weapon, about 2” long

-Zip Ties

Tools list:

-Hot Glue gun

-Soldering iron with solder

-X-acto knife


Step 1: Body Design

First make a template for the body so you can cut out the foamcore to the correct sizes and shapes easily. Dimensions are in fig. 1. Then draw out where the holes for the electronics need to go(fig. 2), and figure out which layers they need to be cut out from. Make sure your wheels are centered in the middle of the body.

Step 2: Body Construction

Cut out 13 copies of the silhouette, then number each layer. You can glue layers 1&2 together now. Using fig. 2, cut out the holes in the layers listed above for their corresponding color/ pattern. Cut a small channel for the wire of the weapon motor in layer 4, so the wire can go into the main compartment. You will glue the layers together as you add the electronics, as described in Steps 5&6.

Step 3: Electronics Wiring

The electronics for this is relatively simple, basically everything plugs into the receiver. The battery plugs into the channel labeled BAT, the motors for the wheels plug into CH1 and Ch2, and the motor for the weapon plugs into CH3. The black wire (the ground), always goes on the outside. If any of your wires don’t have a connector on the end of them to plug into the receiver, you will need to solder one on.

Step 4: Electronics Placement

One of the strengths of this robot relies on how well you package the electronics. As you assemble layers, it will become pretty clear where each servo, battery pack, and receiver goes. The battery pack is fairly heavy and helps add to the strength of the robot, so it gets placed towards the center. The two wheel servos get laid on their side (to minimize their height) in the slots on either side of the battery. The small weapon servo is placed in the front compartment. The receiver is placed on top of the battery pack with the receiving end facing out. All electronics are hot-glued in place.

Step 5: Wheel Mounting

The wheels themselves are Lego wheels and get screwed onto the hubs that are connected to each wheel servo. Not much to say here.

Step 6: Remote Control

This project utilizes RC controls. Each receiver is uniquely paired with an RC controller, so there shouldn’t be any hoops to jump through in that regard. When you turn on your battery pack and controller, your motors will probably start to spin. Trim this excess spinning using the x- and y-axis positional dials to the side of and underneath each thumbstick on the control. Work on centering the dials until the wheels stop spinning.

Step 7: Drive

The controller is pretty straightforward: Pushing the right thumbstick forward will send the robot forward. The same is true about backward and turning left and right. The left thumbstick is for the weapon motor. This thumbstick can be pushed all the way up or down and left there to ensure maximum speed on the weapon. Pushing the thumbstick in the opposite direction will reverse the direction of the weapon.