Low Cost Robotics:
Using Vex in FRC
Art Dutra, III: mentor &
Arthur Dutra, IV: team member
FRC Team #228 “GUS” Robotics
Introduction
If your team can’t:
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Build an entire “practice” playing field
Build a second “practice” robot
Test multiple drive train configurations
Test multiple manipulator designs
Easily teach students programming
Test sensors and autonomous code during the build season
Assess your robot’s scoring potential before competition begins
Have hours of driver training before your first competition
Develop game strategy before competition begins
Have exciting and interactive demonstrations or recruiting
Then Vex might be able to help
Scaled FRC using Vex
1:3 Scale was chosen based on FIRST’s 2005 Vex Challenge pilot
program. The scale works well for building accurate scale
versions of FRC robots and playing field components which
perform well together.
FRC Team 228
1:3 Scale FRC
2005 “GUS”
Vex “Mini G”
Playing Field Creation
2005 Triple Play Vex Version
• All playing field components were built from
materials readily available at the average
home improvement store.
• Playing field walls 9’x18’ - cost $143.86,
w/ 1/8” Lexan @ driver stations - add
$150.00
• Playing field Soft Tile mat - cost $520.00,
or commercial carpeting - cost $340.00
• Scoring Tetras - cost per tetra $2.90
• End Goals - cost per goal $4.75
• Center Goal - cost $6.25
• Loading Stations - cost per unit $5.89
• Complete practice field - $800 - $1200
Playing Field Savings
Time
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Less than one week to
build entire practice
field.
Goals and other large
field objects do not
need to be
disassembled for
storage.
All materials can be
purchased at local
“Home Depot”.
Space
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Entire playing field will
fit in a standard
classroom.
Maximum robot height
limit less than 6’.
Entire field 9’x18’, with
human player and
driver areas 15’x24’.
Entire field will store in
the average closet
without disassembling
goals.
Cost
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Entire playing field cost
$900 - $1200
Playing field
components in future
years (less mat and
walls) cost $230 $330.
Components damaged
during practices or
demonstrations are
less expensive to
repair or replace.
Robot Creation
2005 Triple Play Vex Version
• Practice robots need not be built entirely from
Vex components. Keep robot accurate to full
sized robot.
• 2005 dimensions 9.3”x12.5”x20”.
• Starter Kit, cost $299.99
• Extra Hardware Kit, cost $79.99
• Gear Kit, cost $12.99
• Chain & Sprocket Kit, cost $29.99
• (2) Omni-Wheel Kits, cost per kit $19.99
• Motor Kit, cost $19.99
• Limit Switch Kit, cost $12.99
• Power (battery) Kit, cost $49.99
• Total Robot Cost $525.92
photos from
www.syraweb.com
Robot Savings
Time
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One or two days to
build Vex robot using
one or two
experienced students.
Different prototypes
can be built every day
or two.
Practice robot is up
and running long
before full sized robot
is completed and
shipped.
Changes to full sized
robot can be
duplicated on practice
robot quickly.
Space
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Practice robot fits in a
milk crate.
Six or more robots,
spare parts, batteries,
chargers, and operator
interfaces will fit in a
storage cabinet or
closet.
Workspace for building
and repairing robot is
less than 4’x8’.
Cost
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Entire practice robot
cost $400 - $600
A fleet of practice
robots can be built
over a few years.
Consumable
components less than
$100 per robot per
year.
photo from
www.vexlabs.com
Prototyping Drive Trains
• Nearly any idea imaginable
for possible robot drive trains
can be reproduced in Vex.
The following robot drive
systems can be made out of
Vex components:
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2, 4 or 6-Wheel Tank-Drive
Tank Treads
Crab (swerve) Drive
Holonomic Drive
• Other ideas, including
mecanum drives, can also
be built using custom made
components Vex.
photos from
vexlabs.com
Prototyping Pneumatics
• As with the full-size robots, pneumatic
components can also be used with Vex.
• Innovation FIRST and VexLabs sell Vexcompatible pneumatics kits.
• The kits are easy to work with, and can
accommodate both single and doubleacting pistons.
• The solenoids can plug directly into the
digital outputs on the Vex Controller
without any need for an external power
supply.
• The solenoids can be controlled via the
Vex Transmitter using simple EasyC™
coding.
photo from
www.vexlabs.com
Prototyping Manipulators
• Using Vex components, a
wide range of arms,
elevators, and
manipulators may be built.
• When geared correctly,
powerful, yet fast, arms
can pick up objects
weighing several pounds.
• When used with
pneumatics, the diversity
of designs increases
vastly.
photo from
www.vexlabs.com
photo from
www.vexlabs.com
Programming
• With the new Vex Programming
Kit, endless possibilities are
opened. Now, robots can
autonomously navigate obstacles
using a variety of sensors.
• Using a simple graphical user
interface (GUI), novice
programmers with no C
programming experience can
jump right in to EasyC™.
• EasyC allows for drag-and-drop
simplicity for generating code,
while still allowing for advanced
line coding.
• MPLAB can also be used to
program the Vex robots.
Screenshot from
www.intelitek.com
photo from
www.radioshack.com
Sensors
• Currently, there are six
different sensors available
through the Vex line. These
are:
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Limit Switches
Bumper Switches
Ultrasonic Sensors
Shaft Encoders
Line Tracking Sensors
Light Sensors
• In addition to the Vex
sensors, non-Vex analog and
digital sensors can be
connected as well. These
non-Vex sensors may
include potentiometers,
accelerometers, gyros, and
more.
photos from
www.radioshack.com
Autonomous Code
• Using either EasyC or MPLAB,
autonomous code can be easily written
and executed.
• Novice users can easily write code to test
in EasyC.
• Developing autonomous code by using
Vex robot can be much safer than having
a full-size 130-pound robot’s code go
amok.
• Since Vex robots can also be built much
faster than a full-size robot, the
development and testing of autonomous
code can begin much quicker, since they
would have separate (Vex) robot to test
on.
photos from
www.syraweb.com
(from the WPI Frontiers Savage
Soccer Game)
Driver Training
• Since a Vex robot can be built
within a matter of hours, driver
training can begin much
sooner than usual.
• Teams can create a scaleddown version of a team’s full
size robot in Vex (with an
accurate arm/manipulator) and
scale playing field
components.
• By allowing the drivers to
practice with Vex robots, this
does not disturb the build crew
as they work on the full-size
robot.
photos from
www.vexlabs.com
Scoring Potential
• Teams can accurately estimate their scoring
potential by running their Vex robots on a scale
Vex playing field.
• During the design phase, teams often end up
with two radically different designs about how
the robot should be built.
• Both teams can now build their ideas to test
them head-to-head, to see which idea really
works better.
• Actual practice with real robots beats any
scoring simulator, as this accurately represents
the real world variables (such as driver skill,
coordination, robot interference, etc) in a real
world application.
Game Strategy
• An entire 1:3 scale playing
field can fit into one
classroom, and multiple vex
robots can be built for under
$1000.
• This allows for teams to build
radically different robots, and
have these different Vex
robots compete, as if one
were an opponent.
• This can find the strengths
and weaknesses in any
particular strategy better than
anything else.
photo from
www.usfirst.org
Recruiting and Demonstrations
• Team demonstrations can now
become much more interactive with
the use of Vex.
• Because of safety concerns, letting
random people drive a full-size
robot cannot be allowed.
• But because Vex robots are small,
and are not dangerous, people with
no experience can drive robots as
much as they want with little
supervision.
• By being able to drive a robot and
interact with it, potential team
members will be more likely to join
a robotics team.
The End
Thank You
Additional Information can be found at:
www.vexrobotics.com
www.vexlabs.com
www.chiefdelphi.com
www.team228.org
www.syraweb.com