Do you remember going to the science museum as a kid? Everything was so interesting and mystifying! Robots in particular are mysterious. They appear to have a life of their own, but are actually simple machines. Unfortunately, for children even something as simple as the arduino development environment only adds to the mysterious impenetrability of electronics and robotics. Lego Mindstorms succeeds in demystifying all the grown up abstractions of programming and that is why I love using it to teach!
To get my summer campers interested in robotics, I needed to design something simple, interactive, and exciting enough to keep the attention of a 5 year old. I began with the ‘start here’ tutorial robot on the first page of the manual. It has a solid base with a convenient third servo positioned at the front. Great! That servo will interact with the environment!
Now, what to sense? By far, the coolest sensor in the NXT kit is the color sensor. It can detect individual colors, or larger chunks of the visible spectrum. So what differently colored things can we poke? BALLOONS! Balloons are cheap, come in all colors, and best of all they turn our wimpy servo arm into a cacophonous claw cannon!
At this point we have a robot with an understandable task, brightly colored balloons to throw at the robot, and a pointy mechanized claw…
I then built a safety corral to keep balloons in and children out!
This was my first Mindstorms project. The programming is entirely intuitive and allowed me to create the Balloon Bot program in under 20 minutes! It is easy to change the program to attack different color balloons, search in a wider radius for objects, or distinguish boundaries from balloons. A larger, though more dangerous, needle would increase consistency of successful pops.
The range of the color sensor is quite small. If the sensor is not placed directly against the surface of the balloon, it will give an inconclusive reading. The light sensor needs to be angled upwards to get an accurate reading of the convex surface of the balloon.
The robot uses a sonar distance sensor and a color sensor. The sonar detects objects and senses when they are close enough to the light sensor . If the object is blue, Balloon Bot brings down its push pin arm and laughs maniacally.
Best camper quotes:
“That’s the smartest robot I’ve ever met!”
“I’m going to save all my money probably until I’m eight to buy a lego robot!”
“Excuse me, is it alive?”