Demo Robot Ideas?

Hey guys. I have a fairly small (old base kit plus random extras) amount of Vex parts on me and I’m tasked with building a demo robot. The specifications I’ve set out for myself are that it has to be simple enough that any random layperson / kid could drive it without much chance of self destruction, it must do something cool or be cool, and it must be educational. (That last one is easy; anything with gears will demonstrate ratios, a holonomic base will demonstrate kinematics)

So now I know what it has to do in order to be successful, but I’ve never been very good at brainstorming. Anyone got any “cool” ideas for a simple little robot? I can program basically anything onto it and I can spend a little ($50 or so) on extra parts to make it better. I have 4 motors and a servo for power.


What is your audience? What will impress a “first contact” is different from what impresses a veteran, or at least a person with some exposure, and age will also determine what works as well.

I regularly give a 45-minute demo to non-robotic 5th graders using the Flexigearbot, instructions downloadable here. I slap on an ultrasonic sensor, a bumper sensor, and a line tracker sensor and cover the following concepts.

  1. Gear ratios – I call for student volunteers to exchange gears, and the class watches the robot go from geared 1:1 to geared up to geared down.

  2. Sensors – I demonstrate the Scaredybot (see manual at above link), and the students can activate it without actually touching the bot. Alternately, I get them to switch the motor wires on the drive wheels, and the Scaredybot becomes the Pit Bull bot (attacks instead of retreating). I also try to get them to name devices with sensors that they may have at home that are similar (roombas, light sensors). I jumper between programs to demonstrate a line follower and the bumper sensor.

  3. Program control. I have use of a computer with projector, so I can actually have the class collectively write a program on the spot, which the whole class can see. I let them make mistakes (e.g. turning motors on and off without a “wait” command, making the robot spin by turning both motors in the same direction instead of opposition, etc.)

The above always impresses the target audience (5th graders, their teachers, and their parents). In the past, I’ve tried demonstrating robots with more complicated lifters and grabbers (4-bar lift, tank tread grabber), which were largely unappreciated. Allowing the students to use the remote control has also been disastrous, as a few students tend to monopolize the controls, relegating my primary role to that of police cop. Most of my demos have been to classes of 30+ students; if you have only a few at a time, you may fare better.

There will be a few places this will likely make an appearance, but the target audience is middle and high school students without robotics experience. So it has to be “cool”, interesting to watch, and driveable (“here have the controls”). As far as I understand the venue it’ll be a “robotics booth” at a technology conference, so it’s the kind of thing someone would walk up to for a few minutes, check out, learn something, figure out this stuff is cool, and leave. It’s also going to be used during my FRC team’s “club fair”, so basically the same kind of venue.

One robot that’s fared pretty well at a couple county fairs we’ve done is the Chin-upbot (in the same manual as above). We have a piece of plywood with a PVC pipe bar at the right height. Having the visitor get the robot to lift itself off the ground is reasonably fun and worked well for the small space we had, as it was important for the user to lift carefully, rather than drive fast and far.

tank treads will be “cool” to most audiences, but too slow, and will walk away unless theres is something WAY cool attached to it (an elastic band shooter?)
but a SUPERFAST lightweight robot will draw more attention (people will drive it around the room?)
and the vexplorer claw is a good addon to have
have kids try to pick up a pop can or something

For all of our demos where people need to drive we use the Tumbler-bot. They go fast and are easy to drive. Mostly we have the field set up in an 8’ * 8’ configuration with 3-4 robots going at one time. Last year I had sonars on a few with crash avoidance software running. But most of the time the kids have the tumblers running up to the wall and having it flip over or running over each other.

For more engineering demos we have a walker bot with a claw and a modified protobot with a claw. The proto bot has limit switches to keep it from flipping over etc.

Since you have a limited set of parts I’d build two 2 wheel drive robots so 2 kids a time can drive them.

Our team sometimes does demonstrations at a local children’s museum. We play “square-bot soccer.” Standard tank-drive can be learned in seconds. I’m not sure if you have enough micro-controllers/controllers, but just two motor drive square bots go surprisingly fast.

Use a small green ball from clean sweep. You can make goals out of anything, and a two short stand-offs on the front of a square-bot is enough to control the ball.

The best type of field would be a foam tile, and a wood field perimeter with a small rectangle cut out on each side as a goal. Another type is just two stacks of anything in the middle of an open floor.

Obviously this uses a lot of space and may not be an option for you, but our team has had some very intense soccer matches of 2 on 2.

The Cheesy Poofs’ Screwbot?
[HTML]- YouTube

I had an idea a couple of months ago but our team never went anywhere with it because of FRC season coming in, but I thought a one-man marching band robot would be nice. You could use any percussion instruments and some string instruments. Perhaps wind chimes that are struck by a standoff on a motor, a couple of rubber bands that are strummed by angled pieces of metal on a conveyer belt, some small drums, all on 2-wheel drive. Just something to think about.

If you have any good graphic designers on your FRC team, perhaps make one of the classic “famous” robots, i.e. R2D2, Wall-E, etc.