Kindergarten Robot

lego mindstorms nxt2One of my little projects while on parental leave has been to play around with my Lego Mindstorms NXT 2.0 robotics kit. Apart from being fun for a serious dad like myself, I always had in mind how I could use it with kids to get them interested in technology.

When I was a PhD student in Uppsala back around 2000, we bought a pile of the Lego Mindstorms RCX kits, for use in real-time courses. Obviously, the students loved the opportunity to play with Lego (including the few females). What was less obvious and much more interesting was what happened when we brought in a bunch of children from a local kindergarten to visit — they really took a liking to our little yellow robots running around a classroom. They treated the robots as little animals, wondering what they were doing and why…

With that in mind, I decided to try to reprise this myself with my own son and his kindergarten friends. Last week, I took my robot kit with me and went to meet the kids.

My top-level goal with exercise was really to get the kids interested in technology as a future field of study and venture… you have to start early to counteract the prevalent tendency of people to want to be famous and work in media or something… Only time will tell if this had any effect at all (I doubt it).

In addition to the top-level goal, I wanted to communicate some about how things work. Make technology more understandable and less magical, and more accessible. In particular:

  • Autonomy: the robot is not under remote control, it acts autonomously based on its programming.
  • Sense-compute-actuate: the robot perceives the world and makes decisions that get sent to the motors.
  • Limited sensors: the robot does not see like we do, it uses far simpler sensing.
  • Programmability: the same physical setup can do a lot of different things just by switching to a different program.
  • Concurrency: the robot can do several unrelated things at once.
  • Stupidity: the robot is really dumb and just reacts very predictably to its environment.

I think these points can be brought across using an indirect approach. You cannot tell a four-year-old about programmability. But you can show that if you go to the robot’s control unit and press some buttons it does something different.

Note that some of the points above are artificial, in that you could build much smarter programs with more complex behaviors and less direct reactions. But that would make things more magical and “human-like”, which is not what I wanted to communicate.

Anyway, in the end I used two configurations of a driving base, with a few different programs.

The first configuration is shown below, using a color sensor pointing downwards and an ultrasound sensor pointing forward.It also had a shooter pointing forward (in this picture, the organic styling of the Lego Bionicle Zamor-derived shooter comes across very nicely, as well as the apparently quite special silver- and gold-colored balls I picked up on a sale).


First, I had this robot follow a black line on the floor. Putting the line down was fun, watching the robot follow the line did not work out as intended. Too hard to explain the algorithm for following the contrast between black and not-black. Adding the behavior to stop when the robot hit a red line was also too subtle.

Next, I tried to put the robot on a table with the program “stay within black lines”. Or rather “reverse and turn if you hit a black line”. Problem was that the table had a spotted pattern that included small specks of black, and the robot just kept doing avoidance maneuvers… so that failed. I still want to do a table-dancing robot, but I guess relying on an ultrasound sensor pointing downwards to detect the chasm at the edge will work better.

What was fun though was when I activated the ultrasound sensor and the shooter: the robot would crawl along the line, and if something got in the way, it would fire a ball. That was huge fun! All the kids crowded around to get the robot to shoot and collect the balls. Note for future attempts: dramatic actions are great!

It was even better when I set the robot to rove freely, using the ultrasound sensor to turn when something got in its way. This was an easy-to-understand behavior that the kids appreciated, putting feet and hands in the way of the robot to make it turn. The poor robot was often the center of a pile of kids that were all trying to make it turn.

I also tried a configuration using bumper sensors:

bumberbotHere, the robot only had one program, to move forward until it hit something, and based on the side that hit, back up and turn to avoid hitting the same obstacle again. This was a very successful configuration. The kids started to play “don’t touch the robot” with it, having it drive between their legs or bending over the robot to make a bridge – but not touching it and making it turn.

Note that I did not bring any computer with me, all programs were preloaded on the NXT brick. Very handy, actually.

In summary, I had a great time doing this, and I will be back with new configurations and programs. Creating the programs was very quick and easy in the Mindstorms environment, proving the value of domain-specific programming.

The kids have hopefully learned that you can play with and control technology, and that you should not be too respectful. Maybe someone also picked up some of the ideas I presented at the start of this blog post.

Gender-Theoretical Notes

I do have to end with a slightly sad note.

It was surprising to me just how differently the boys and the girls reacted and behaved. I had assumed that kids would just be kids at this age (three to five years old), with no gender-related differences. It was very striking that this was not the case in reality. The boys just ran in and started playing, and very quite hard to get to listen to anything I had to say. The girls walked in and quietly waited for instructions, and took some warming-up before they would interact with the robot.

I cannot blame our kindergarten for this, they are definitely trying to avoid gender-based stereotypes.I guess it shows that fighting societal norms is just as hard as everyone says it is.

It was also interesting that the kids were surprised to see a parent build with Lego and have a great time. For some reason, that was not expected behavior from a dad. Sad too.

3 thoughts on “Kindergarten Robot”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.