V EX C OACHES ' T RAINING October 12, 2013

Agenda for Today 9 – 10 AM : Tina Reeves and the Engineering Notebook 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 motors 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 braces

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 sync

Sample Drive - Download Select Robot tab and click Compile and Download 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 motor 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 commands 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 boring 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 functions

Program with Functions: Sample 05-Functions Program int fullSpeed = 127; //global variable for full speed int halfSpeed = 64; //global variable for 1/2 speed int quarterSpeed = 32; //global variable for 1/4 speed void forward(int waitTime) { motor[port1]=halfSpeed; //Turn on motors and go forward motor[port10]=-halfSpeed; //desired speed wait1Msec(waitTime); //for desired time }

Program with Functions: Sample 05- Functions 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

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 controls You need to retype Motor and Sensor set up

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 skills 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

When ready to test, compile and download code – 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