78 SERVO 10.2013
measure the distance to objects
in front of them from 3 cm to
250 cm. The sensor emits a 40
kHz ‘chirp’ and then measures
the reflected echo’s return time
to determine the distance.
• The EV3 W745509
infrared sensor (Figure 11)
shows the all new IR sensor
that detects within a proximity
of 50-70 cm to the robot, and
reads signals emitted by the
EV3 infrared beacon up to
two meters. It can be used in
remote-controlled robots to navigate
obstacle courses, and you can learn
how infrared technology is used in
TV remotes, surveillance systems,
and even in target-acquisition
• The Hi Technic W991380 gyro
sensor contains a single-axis
gyroscopic sensor that detects
rotation on the X-Y plane (basic
turning), and returns a value that
represents the number of degrees per
second (±360°) of rotation and the
direction of turning.
LEGO has many more sensors
that can be applied to advanced robot
projects. These include sensors to
measure color, a rotational angle
sensor to be used as a shaft encoder
on wheels or rotating objects, force,
sound, light, magnetic fields,
temperature, air pressure, pH, and
even RFID tags. Most (if not all) of
these sensors can be used with both
the NXT and the new EV3 bricks, as
well as other microcontrollers such as
an Arduino, Parallax Propeller, and
also laptop computers.
Just what is new with the
MINDSTORMS EV3 as compared with
the NXT? It is quite a bit more than
the stunning new white, black, and
The new brick has 64 MB of RAM
with 16 MB of Flash memory as
compared with 256 KB; the LCD
display has 178x128 pixels vs. 100x64,
and a faster Atmel ARM 9-SoC
processor running open source Linux
vs. the ARM 7 on the NXT. The new
features include a micro-SD card
reader, a USB host port, voice control
apps, Apple interconnectivity,
Bluetooth v2.1, three-color
display backlight, a better
speaker, and four motor ports.
IR control via a sensor/beacon
is also available as a separate
The EV3 platform is very
compatible with the NXT
platform. The building systems
are 100% interchangeable,
except that the EV3 sensors
cannot be used with the
NXT brick due to power
constraints. The EV3
software is backwards compatible
to NXT, and NXT sensors function
fully on the EV3 system. It is
important to note, however, that
the NXT and EV3 bricks cannot be
I wanted to delve a bit into
the two previous LEGO MINDSTORMS
bricks before examining the new EV3
(the third generation in the series).
Considering so much information is
available about the NXT, I thought it
prudent to not only survey the new
features of the EV3 as I did above,
Figure 10. LEGO NXT ultrasonic object
and distance sensor.
TABLE 1. Comparing EV3 With NXT.
History Introduced in 2006. Second generation of LEGO MINDSTORMS Education. Introduced in 2013. Third generation of LEGO MINDSTORMS Education.
Building System LEGO Technic LEGO Technic
Software Graphical and icon based. Powered by National Instruments LabVIEW. Graphical and icon based. Powered by National Instruments LabVIEW.
Hardware Intelligent brick, five sensors, three motors, hundreds of parts. Intelligent brick, five sensors, three motors, hundreds of parts.
Multiple options & hundreds of hours of
curriculum for mid to high school STEM.
Many community-generated support
websites and books.
30+ hours of STEM curriculum
available fall semester 2013.
Support One year warranty. Tech support for the life of the product. One year warranty. Tech support for the life of the product.
Availability Now, and sold until the end of 2015. Available fall semester 2013. Sold indefinitely.
Cost per student over
7 years average use Under $3 Under $3
FIRST LEGO League Allowed in 2013 season. Allowed in 2013 season.
FIRST Tech Challenge Allowed and supported in 2013-2014 season. Not allowed in 2013-2014 season.
TETRIX & ROBOTC, LabVIEW
for LEGO MINDSTORMS Supported Support available fall 2013.