Living on the edge


Living on the edge

In this lesson, students will build a motorized vehicle capable of recognizing the edge of a table and hopefully stopping before falling off.
Duration: 2 – 3 sessions of 90 minutes

Credits: Makerspace of Winterthur (Switzerland) public library; Enteron

GRADE LEVEL
Middle School (ages 11-13)
High School (ages 14-17)
College/University (age 18+)

DIFFICULTY
Advanced

SUBJECT
Robotics
Engineering
littleBits Basics
Technology
Art/Design
Science

MODULES & ACCESSORIES USED (16)
light sensor (1)
bargraph (1)
dimmer (1)
power (1)
fork (1)
inverter (1)
threshold (1)
Brick Adapter (3)
wire (2)
DC motor (tethered) (2)
wheel (2)

OTHER MATERIALS USED (2)
LEGO 1
Rubber bands 1

TOOLS USED
mini screw driver

LESSON GUIDE

STEP 1 : Build a basic circuit

Living on the edge1
a first version of the littlebits circuit

Build, try and rebuild a basic circuit which lets you control the motors with a light sensor. To be able to control the speed, you can use a dimmer after the light sensor if you want to.

STEP 2 : Construct the vehicle

The vehicle must be able to house all the electronics. Be sure to construct it with a large building place to allow all elements to be place on it (don’t forget: you need the battery as well as all the bits).

STEP 3 : Combine the two

Living on the edge2
the light sensor is housed inside a lego box

Now it’s time to mount the circuit on your vehicle. This will surely make some changes necessary on both sides. For one, you will need to add wire bits into the circuit. The light sensor needs to be place underneath the vehicle facing down. To get some good results, it will probably be necessary to block all light coming from the sides by building a wall around the light sensor. Make sure that both motors are set to turn in the correct direction, otherwise your vehicle might move backwards or in circles…

STEP 4 : Adjust the screw of the light sensor

Living on the edge3
modified circuit

Now it’s time to fiddle with the light sensor’s settings. Be sure to have all available hands near the table when trying out your circuit. Depending on the colour of the table, different settings might be more successful. I found that on the table I used first, the light sensor had to be set to ‘light’ and I had to place an inverter between the light sensor and the dimmer.

STEP 5 : Suggestions for further improvement

Living on the edge4
have fun!

For better results, I guess you could add a threshold bit after the light sensor. This would probably simplify the process of finding the ‘right’ settings. Unfortunately, I don’t own a threshold bit.