You can also replace the hand crank
with a computer-controlled motor.
Just connect a simple Lego motor
(about $8) to a computer through a
USB port via a Lego hub ($45).
And by adding a Lego motion sensor ($20), you can make the snake
move forward when a hand ap-proaches it. Students can then use the
free programming language Scratch
( scratch.mit.edu) to program the
motor and sensor using a prewritten
script. The program waits until the
gap between an approaching object
and the sensor hits 15 cm, and then
it rocks the snake forward and back
again. Students can also use Scratch to
program the computer to issue a hiss
or another suitable sound for dramatic
effect. The script, prerecorded sound
effects, and directions for the automated snake toy are available at
www.MakeToLearn.org/toys.
Have access to a 3D printer? You can
use it to create a customized plastic
version of the toy that is more durable
and permanent.
Building Mechatronic Toys
A new field of engineering called mechatronics combines mechanical engineering, electronic engineering, and
computer science and makes all three
disciplines accessible to surprisingly
young students.
In one striking illustration of the
possibilities, Stewart Watkiss collaborated with his 5-year-old son and
7-year-old daughter to create a “bee
box” using the Raspberry Pi with
Scratch. A magnet in an artificial bee
closes reed switches beneath the lid of
a shoebox as you move it across the
top of the box to places of interest for
the bee, like a blossom or its hive. A
Scratch script running on the Raspberry Pi generates an image of a flower on the screen when the user moves
the bee to the physical flower on the
box, then displays an image of a hive
when the bee returns to the beehive.
Watkiss’s son constructed the
physical box and wired it with some
assistance from his father. Then his
daughter created the simple Scratch
CONNECTED CLASSROOM |
Creating Cardstock Mechanisms
The essence of engineering is designing, building, and testing prototypes
while optimizing solutions. Inspiring
iterative thinking and decreasing the
costs of failure are key to forming the
habits of mind we hope to cultivate in
our students.
Although high-tech tools, such as
3D printers, can enhance the types of
mechanical models you are able to develop for your classroom, you can also
construct surprisingly sophisticated
models with just a pair of scissors
and cardstock.
Rob Ives, a Scottish math teacher
who began constructing mechanical models for his classroom and now
designs them full time, created a cardstock mechanical toy that illustrates
how a crank mechanism works through
the movement of a playful snake (see
the photo on page 35). You can also
build variations on this theme, such as
a giraffe or dragon toy. For $15 a year,
you can get a classroom license at Rob
Ives.com that provides access to hundreds of models like this as well as suggestions for construction techniques.
But mechanical models are just the
beginning. With a little ingenuity and
some inexpensive add-ons, your students can creatively enhance any basic
mechanical toy.
Adding Electronic Extensions
These kinds of construction opportunities can give our students a feel for the
movement and mechanics involved in
machine processes. Automata also do a
superior job of demonstrating systems
thinking with input, process, output,
and—with a little help from electronics—even feedback and control.
For example, the Albert Einstein Fellow James Town replaced the eyes in
Ives’ snake toy with LED lights. When
you turn the crank, brush contacts light
up the eyes alternately at different points
in the cycle, which could illustrate parallel and serial circuits in a unit on electricity and magnetism.
When a user moves the bee across the top of this “bee box,” created by 5-year-old
Oliver Watkiss and his father, a hidden magnet and reed switches activate a Scratch
script written by Oliver’s 7-year-old sister to generate images of a flower and a hive
on a computer screen.
