Battle Bots on a Budget

As an avid reader of Make Magazine for over 10 years, I've read dozens of stories about the Maker Faires that happen every year across the country. Finally, in 2014, I packed up the family and headed three hours South-East to one of the largest of them all in NYC. It was an inspiring trip in so many ways - from the kinetic sculptures, to the Power Racing Series, to the costume builders. But in the months following our trip, I found myself reflecting not on these epic displays of craftsmanship and skill - but instead on a tiny activity center from the kids section. It was there that we watched a group of kids hastily taping tacks and paper clips to the front and sides of some small remote control vehicles. They then battled 'to the death', trying to pop the balloon that was taped on to their opponent's vehicles.

As someone who is always on the lookout for ways to engage my kids in activities that show them how fun it is to engineer and build things - I immediately saw the genius in this activity. It makes the engineering process accessible and fun to kids of all ages. Design. Build. Test (Battle). Learn. Repeat. It has it all.

After returning home, I started researching what it would take to replicate this version of 'Battle Bots' for my own kids. There wasn't much on the web so I ended up improvising a bit - and coincidentally ended up with a faster, more violent, and more fun version. Hopefully this Instructable will inspire you to try this with your kids (or colleagues, or friends) - and unleash the engineer within!

Step 1: Materials and Tools

Gather your materials: Other than the RC vehicles, most of these materials can be found at the dollar store.

* (3) RC vehicles: I researched many different RC cars on Amazon from $50 down to $10. The reviews on the cheaper ones indicated that they had poor ground clearance and low power. We settled on a $42 model (click here for Amazon link) - and these ended up being perfect. They had many advantages, including tons of power (enough to flip other cars), 3 channels (so three cars can be used at once), and a large, flat surface under the plastic body. In our version of Battle Bots, each team is given a cardboard vehicle body that they add weapons and armor to for battle. This flat surface it perfect for mounting the body.

* cardboard

* hot glue sticks

* wooden skewers

* popsicle sticks

* balloons

* safety goggles

Gather your tools:

* utility knife

* hot glue gun

Step 2: Building the Bodies

Each team is given the exact same cardboard body to start with. I designed these bodies to be simple and easy to make. I also wanted to provide as much of a blank slate as possible for the competitors to work with.

The body is slightly longer than the length of the RC car, and wide enough to cover about half of the wheel on each side. When using these particular RC cars, I found a body dimension of 12.75 x 5.0 x 1.25 tall to work well. The flat pattern is cut from a large piece of cardboard. I used the edge of a metal ruler to create sharp folds in the cardboard. The corners were hot glued to create a 5 sided rectangular box.

With the box placed upside down on the table, I hold the car upside down over the top of it and center it front-to-back and left-to-right. I then push the car down into the cardboard to make 4 holes for the attachment posts. The car is then positioned upright on the table and the new body is placed on top. I sketch the wheel wells and then cut them out. You may need to trim them a couple of times to makes sure there is adequate room for the suspension travel and pivoting front wheels.

Step 3: Establish the Ground Rules

To keep the competition fair and fun, it is important to establish a consistent set of rules. Below are the guidelines that we used, but feel free to experiment to keep it interesting.

Objective: To pop your opponents' balloons before they pop yours. The last vehicle with an un-popped balloon wins!

Materials: Each team is given a simple cardboard vehicle body to start with. They are free to add to it with armor and weapons. We typically limit our materials to cardboard and common office supplies. This keep the cost down and drives a surprising amount of creativity. We do limit the number of wooden skewers (typically 4 or 6) so that the builders need to make choices as to how to best use them.

Balloon placement: Balloons are placed on the back surface of each vehicle. We cut a notch in the cardboard and slip the balloon knot into this notch.

Material placement: We allow material to be added to all surfaces of the cardboard body with only one limitation. We don't allow anything to protrude beyond the back surface of the cardboard body. This is done so people don't shield their balloon with cardboard.

Size restriction: We typically don't restrict how much material can be added to the body. What we've seen is that the more stuff that is added, the more susceptible it becomes to breaking off during the battle.

Number of competitors: Only 3 people can compete at once, but it's easy to have a competition with many more. With larger groups, I make a cardboard vehicle body for each team. All teams have the same amount of time to modify their body. We then have a round-robin style tournament. We typically don't allow the winner of each round to fix their car between heats

Time limit: We limit the build time - anywhere from 5 minutes to 20 minutes. This is typically driven by how many people will be competing.

Step 4: Prepare for Battle!

This step is almost as much fun as the actual battle. Get creative! Most of the designs center around gluing the skewers to the front and sides of your car, but there are so many different ways to turn your cardboard box into a war machine. You can try to build a 'scoop' to flip your opponents car, thus immobilizing them for an easy kill. Or you can make one long spear that can reach over your competitors armor and pop his/her balloon. The competitors will learn from each competition and as time goes on, change up their car to better fit their strategy.

Another part of this step is to make sure that everyone gives their car a name (mine is always "Rainbow Kitty Popping Tart"), and that each car is decorated with some flair. Whether it be with some colorful flames, an inspirational quote, or burning skull... this added character make the battles that much more fun.

Step 5: Let the Battle Begin!

Finally! Pop some fresh batteries in the cars, and get ready for some carnage. We usually position the cars in opposite sides of the room (or yard, or garage), and start the competition with a "ready, set, GO!". The smaller the space, the quicker the battle. We can usually get through a dozen rounds in an hour. By they time we are through, the floor is littered with popped balloons.

I can't overstate how much fun it is to battle. I've organized these Battle Bot competitions with my own kids (middle schoolers), with elementary school students, and with my co-workers. It really is fun for all ages. It's a great way to teach STEM skills to kids, or to help with team building in the work place. Give it a try and I promise you'll love it!

Word of caution: I listed eye protection in the material list for a reason. It's easy to carry these armored vehicle bodies around without being totally aware of how far out some of the wooden skewers extend. Kids, especially, are not always as careful as the need to be. I highly recommend that you make sure the kids wear goggles when the make the cars and when they compete.

We've discovered some other wrinkles that can be added to keep the competition fresh:

* Spiked obstacles: We've taken cardboard boxes and added skewers to them to make them a stationary hazard. You can push your opponent into them, or use them to as a defensive blockade.

* Roaming vehicle of death: Nominate one of the three competitors to be a free radical. Their vehicle doesn't have a balloon and can't be killed. Their only job is to try to kill the other two.

* Sans balloons: Ditch the balloons and design your cars to flip your opponents cars. This is more in line with the Battle Bots TV show. The last vehicle standing wins!