(PPTX, Unknown)

October 12, 2013
Agenda for Today
• 9 – 10 AM : Tina Reeves and the Engineering
• 10 – Noon : Finish Building, Basic Robot C
• 12-12:30 : Lunch
• 12:30 – 2:30 Basic Programs, Functions,
Robot C Video Trainer, Setting up
Competition Template
• 2:30-3:00 Wrap up, Clean Up
Engineering Notebook
Continue Building
• 4 motors wired as last
step in build
– 3 to 2 wire converters
• Get charged battery
• 9V back-up battery?
Program Basics – Drive Motors
• Motors to achieve “tank drive”
– Left stick (ch3) drive left wheels
– Right stick (ch2) drive right wheels
– Other modes: Arcade – 1 stick drives and turns
• Left drive motor connected to Port 1
– Port 1 is a dedicated 2 wire port
• Right drive motor connected to Port 10
– Port 10 is a dedicated 2 wire port
• For today, VEXnet joystick will control drive
Program Basics – Arm and Claw
• 1 motor dedicated to raise and lower arm
– Port 7 will be used with a 3 to 2 wire converter
– We will assign it to Ch2 on partner joystick
• 1 motor used to open and close the claw
– Port 6 will be used with a 3 to 2 converter
– We will assign button 5U to open claw
– We will assign button 5D to close claw
Writing a Basic Program
• All new files begin with
task main()
Code you want the robot to run goes between the
Writing a Basic Program
• After task main()
– All code that needs to be continuously executed
must be enclosed in a while () statement
while (true)
Sample Drive Program
Sample Drive - Download
• Once program is entered
– Click Robot tab and select Compile
• You will be asked to save file
• Give it an easy to identify name
• Use Wireless programming cable
– Connect USB side to same port on computer
– Connect phone jack to VEXnet joystick
– Turn on Cortex and joystick and wait for them to
Sample Drive - Download
• Select Robot tab and
click Compile and
• Program will be sent to
Cortex over wifi
• When done, click on
Start and disconnect
phone jack
• Drive!
• May have to reverse
negative sign.
Other Programming Method…
• New programming wireless kit exists
– Provides constant power to joystick
• You can use USB A – A cable
– Connect cable to Cortex directly
– Compile and Download
– Reset Cortex afterwards and sync with joystick
– Be careful with this method
• Continuously removing/inserting VEX key will lead to
undue wear and eventual VEXnet issues
Complete 2 Joystick Program
Notes on Motor Speed
• In VEX, motor speed and direction controlled
by a +/- number between -127 and +127
– Negative 127 is full on “reverse”
– Positive 127 is full “forward”
– Sometimes, we switch the sign
– Zero is always “Stop”
• Any value in-between can be assigned to a
• Analog joystick Ch 1,2,3,4 return such a value
A simple Autonomous Program
• This program will take drive commands away
and make the robot run entirely by a string of
• See Sample Program 03 – Simple Auto
Combine Programs to Make a
Homemade Competition Template
• Every VEX game has a an Autonomous and
Driver modes
– 15 seconds Auto
– 1min 45 seconds of driver commands
• Sample 04 – Homemade Competition will
combine the two previous examples
Homemade Competition Template
• You can copy and paste simple autonomous
in the 15 second section
• You can copy and basic drive commands into
the 1min 45 second section
More Efficient Program…
• Writing the same code over and over gets
• Better to write it once and recycle
• In Robot C, Functions are segments of code
that can be called upon whenever needed
– You can pass a variable to Functions
– Functions can return values
• For us today, we will just use simple variable accepting
Program with Functions: Sample 05-Functions
int fullSpeed = 127;
int halfSpeed = 64;
int quarterSpeed = 32;
void forward(int waitTime)
//global variable for full speed
//global variable for 1/2 speed
//global variable for 1/4 speed
//Turn on motors and go forward
//desired speed
//for desired time
Program with Functions: Sample 05Functions Program
Better Motor Definitions
• Using Port # is cumbersome
– Any changes in port assignment means changes
through whole program
– Port # doesn’t tell you anything about the
function of the motor when reviewing code
• Better to use a labeling system to set motors
and sensors
– Under Robot Tab
• Motor and Sensor Setup
Motor and Sensor Set Up
Motor and Sensor Set Up
Motor and Sensor Set Up
• We label left motor on port 1 – leftDrive
– Set it as a 393 regular motor
• We label right motor on port 10 – rightDrive
– Set it as a 393 regular motor
– Note we selected to reverse it
– Program will now handle inverted motors
• Claw on port 6 – clawMotor
• Arm on port7 - armMotor
Motor and Sensor Set Up
• Program adds the following header
– Don’t modify directly
– Any edits should be done in the window
• This will make changing port numbers later
on much easier
Sample 06 – Sample Program
Competition Template
• Once all code has been debugged and tested to
satisfaction, time to copy and paste it to
competition template file
• Competition Template is a sample program
found under File->Open Sample Program
– Select VEX2 ->Templates
– Open VEX_Competition_Template
• You can Copy and Paste your variables,
functions, autonomous commands, and driver
• You need to retype Motor and Sensor set up
Competition Program
Competition Program
Competition Program
Competition Program
Competition Program
Robot C Curriculum Trainer
• Step by Step Instruction Series of videos and
documents that teach how to use Robot C
VEX Cortex Video Trainer
Virtual Worlds
• You can start practicing your programming
• Lets you virtually control a preset robot with
defined motors and sensors
• Can play Toss Up
• You must change Compile Target to Virtual
World under Robot Tab
Virtual Worlds
Virtual Worlds
• When ready to test, compile and download
– Virtual World will launch
– Can click start and test
– Login as Guest
• Can also drive robot around to practice
– Must select Robot Skills mode
– AWSD steers, <> raises arm, ; ‘ open close claw
Virtual Worlds

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