Building vibrobots in the classroom

Robots can no longer be excluded from society. In industry giant robotic arms are used to build cars, sorting of food and other purposes. At home, you might have a robotic hoover or lawnmower. But what makes a robot a robot? In this lesson, we depart from the question What is a robot? and Can we build a robot? The result is a STEM-activity of several lessons around various themes like electricity, robotics, science and engineering, mechanics or even biology and art.


What is a robot?

We start with a class discussion about robots. Some pupils will undoubtedly have seen the movie Big Hero 6 or Wall-e which feature robots in the lead role. Many children will have heard that giant robotic arms build cars in factories or perhaps they have a robotic hoover at home? Allow the children to come up with as many fictive and real examples of robots that they can think of. Another question could be When do we consider a machine to be a robot?. Wikipedia offers a possible definition for a robot in English. A robot would not be a robot without moving parts. When we asked children How does a robot move? they came up with examples of driving and crawling robots.

Give it a go

Robots usually consist of a processor (eg. a computer), motors, a power supply (eg. a battery), mechanical parts and sensors. Although the Dwenguino tutorials are ideal for learning to program a robot, here we focus on a cheap and basic robot, with a motor, a battery (and battery holder) and some arts and crafts materials. The following materials are needed per pupil:

  • 1x 1,5V - 3V DC motor, for example this one on Opitec;
  • 1x AA battery (students can bring their own rechargable batteries);
  • 1x an AA-batterypack with wires;
  • a variety of arts and crafts materials, such as stickers, feathers, cups, screw terminals, lollypop sticks, metal wire,...
  • a variety of sticking materials like tape and rubber bands.

By choosing the right materials and by making large purchases, the price per robot can be limited to about £2 per robot. Share the materials amongst the students and begin to offer some explanation about motors and batteries. As you know, a battery a positive (+) and a negative (-) end. Connecting the two causes a short circuit and causes the battery to heat up and even explode. Therefore ensure that you explain to all children what a short circuit is and what they can do to avoid it.

Motor, battery and holder

Following the instruction about the motors children can start to experiment. What happens when the battery is connected to the motors? What changes when two batteries are used (in serial or parallel configuration) In order to let a robot vibrate, it is necessary to attach a weight to the motor shaft. When the motor is activated with the weight attached, it affects the balance and causes the motor (and robot) to loose balance. To attach a weight, a screw terminal and metal wire can be used as in the example below:

bibberbot motor en lusterklem

Designing a robot

Now that the pupils have acquainted themselves with the different materials and their characteristics, they can begin to design a robot. There are several available options. You can give the students absolute freedom or give them a set theme (for example vibrating insects, drawing robots,…). Although we prefer that pupils use their own creativity, it is often easier for them to work within the boundaries of a set theme. Just avoid to give specific or offering step-by-step instructions. It may be easier for children to follow step-by-step instructions, but the freedom of design is needed for children to develop their creativity and problem solving skills!

Building a robot

The vibrobot can be built with every-day materials, which can be found in every home or school. Ask the pupils to bring a wire cutter and a flat screwdriver to ensure that enough tools are available in class. The wire cutter can be used to make the robot’s metal wire legs and the weight on the motor etc, while the screwdriver is needed to attach the screw terminal to the motor shaft.

The battery pack needs to be attached to the connectors of the motor. The polarity does not matter since it only determines the direction of the rotation.

After 90 minutes of cutting, pasting, folding,… the following results appear:

voorbeelden

Of course you can be even more creative and build a vibrating dino-bot:

vibrobot dino

Testing and improving the vibrobot

An important part of STEM-education is the evaluation. Teach your pupils how to approach their design critically. Is the result close to the idea they had in mind? Could they find a way to increase the speed? How can I make adjustments to manage the direction of the robot’s movement? Perhaps there is room for a contest or an exhibition?

Many thanks

Many thanks to the pupils of the primary school the Mozaïek and the FYXXI-lab in Ghent, Belgium, for their enthusiasm to build their very own vibrobot.