Wiki

Vex Forum Index / FAQ / Wiki

The purpose of this topic is to make it easier to find vast amounts of knowledge already available on the Vex Forum and related sites.

Any forum user with high enough trust level could edit this Wiki and all contributors are welcome.

However, to maintain high quality, everybody has to adhere to the Wiki Style and Guidelines, detailed below.

Please, DO NOT CREATE NEW POSTS in this topic, unless you have a prior approval from the Wiki maintainers team.

Also, please, read the guidelines to find the link to the open discussion topic, as well as instructions how to be a good Wiki editor.

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Master Index

  1. What every VEX Forum user needs to know

  2. What every Student needs to know about VEX

  3. What every Teacher or Mentor needs to know about VEX

  4. What every Parent needs to know about VEX Robotics Competition

  5. External websites and user communities

  6. Frequently used acronyms

  7. VEX Forum Wiki Rules and Style Guidelines

Details (level 1)

  1. Building the robot — what constitutes the robot — basics

  2. Overview of common chassis types

  3. Overview of frequently used lift types

  4. Overview of frequently used intakes

  5. Best building practices

  6. Other important build topics and examples

  7. Programming environments, links to help and tutorials

  8. Programming: Getting Started with VEXcode

  9. Programming: Common Beginner Mistakes and FAQs

  10. V5 Architecture and Troubleshooting

Details (level 2)

  1. Engineering Design Process

  2. Engineering Notebook Resources

  3. CAD software: links, tutorials, tips

  4. Preparing for competition day

  5. Tips for how competitions work

  6. Beyond the competition

  7. School based vs. independent teams; fundraising

  8. Tips for organizing a team

  9. Tools

  10. Alternative part sources

Specific subsystem designs (detail level 3)

  1. Omni-wheel tank drive

  2. X-drive

  3. H-drive

  4. Mecanum wheels

  5. [Reserved for other drivetrain types]

  6. Clawbot / 2-bar lift

  7. 4-bar, 6-bar, 8-bar, etc.

  8. Double-reverse 4-bar (DR4B)

  9. Scissor lift

  10. Cascade lift

Intakes / manipulators

  1. Simple claw

  2. Horizontal intake rollers

  3. meaning of life

  4. Top rollers

  5. [Reserved]

Ball launchers

  1. Flywheel

  2. Puncher

  3. Catapult

  4. [Reserved]

  5. [Reserved]

Specific sensors / programming

  1. Bumper switch, limit switch, jumper

  2. Potentiometer

  3. Encoders

  4. Gyro

  5. Line follower

  6. Light sensor

  7. Ultrasonic/sonar/rangefinder

  8. Accelerometer

  9. Vision sensor

  10. [Reserved for LIDAR]

Advanced programming topics (general)

  1. Driver control (teleop): arcade, split arcade, tank controls

  2. Joystick control scaling, deadband

  3. Macros

  4. PID control

  5. Autonomous: async timing

  6. Autonomous: driving straight

  7. Autonomous: turns

  8. Odometry, navigation

  9. State machines, sequences

70-79. [Reserved for more programming topics]

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What every new Forum user needs to know

A majority of the questions about the current VRC game could be answered by reading Tower Takeover Game Manual, Official Q&As, or Unofficial Tower Takeover FAQ thread.

If you still have questions regarding the game rules, try searching the forum: https://www.vexforum.com/search


  • Search the forum before you post
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    Use the formatting toolbar in the post editor. If you’re really committed, check out the Markdown manual.

Footnotes
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  2. The post and title edit features are disabled 24 hours after posting.

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What every Student needs to know about VEX

Top Things Someone New to Vex Should Know

TBD

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What every Teacher or Mentor needs to know about VEX

VEX Coding Studio is obsolete and have been phased out.
Use VEXcode instead: https://www.vexrobotics.com/vexcode

Additional material are available at VEX knowledge base: https://help.vex.com

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What every Parent needs to know about VEX Robotics Competition

Student-Centered Policy Document

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External websites and user communities

(Work in progress / to be organized)

External websites with Reference materials

Advanced Programming Links

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Frequently used acronyms

VRC - VEX Robotics Competition (main site: http://robotevents.com/)

GDC - Game Design Committee

RECF - Robotics Education & Competition Foundation (https://www.roboticseducation.org/about-us/)

VEX - It is not an acronym (VEX Robotics: www.vexrobotics.com)

EDR - It is not an acronym (https://www.vexrobotics.com/vexedr)

VCS - VEX Coding Studio

VC - VEXcode

DRow - Banhammers and Comic Relief

Abbreviations in Forums

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VEX Forum Wiki Rules and Style Guidelines

As was already said in the introduction, the purpose of this topic is not to duplicate vast amounts of knowledge already available on the Vex Forum and external sites, but to make it easy to find that information.

We welcome and value all contributions and currently any forum users with TL1 trust level could edit Wiki posts.

However, to maintain high quality of the Wiki, everybody has to adhere to the Wiki Guidelines, that are detailed below.

Please, DO NOT CREATE NEW POSTS in this topic, unless you have a prior approval from the Wiki maintainers team (TBD).

Current open discussion about this wiki could be found in this thread: VEX Forum Wiki

This Style and contribution Guidelines are work in progress and we are going to define and put them here in the near future…

In general, the preference is to stay brief and, whenever possible, use a link to an existing topic, instead of copying its content into the Wiki.

Strategy

We could start by listing things “we wish we knew at the beginning” and then sort them into beginner / intermediate / advanced categories.

Beginner category is something that needs to be communicated right away.
Intermediate is something that could wait until later in the season or second season.
And advanced is something (like odometry/tracking) that would be great to get to, but is not required by most of the teams.

If we use pyramid diagram, then we could start from the top with the most basic and most important knowledge, then expand it into intermediate level, with more information that relies on more prior experience, and so forth …
block-pyramid

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Building the robot - what constitutes the robot - basics

VRC Legal definition of the robot (according to the Game Manual <R1>)

TBD

Example

https://www.youtube.com/watch?v=3yedhYdeiLM

Details

Brain, Battery, VexNet, and most importantly license plates: 7580A 2015 Robot Reveal.

Just kidding

https://help.vex.com/category/369-engineering

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Overview of common chassis types

How could we help a new team to choose a chassis for the robot?

Drivetrain Type Pros Cons
1. All omni tank drive - easy to build - can be easily pushed to the side
- 2 or 4 motors
- can be chained front-back
2. H-Drive - all advantages of tank drive - needs extra motor
- tricky to distribute weight
3. X-Drive - resists pushing - harder to build
4. Mecanum TBD TBD

Omni wheel vs Mecanum

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Overview of frequently used Lift Types

  1. 2-bar
  2. 4-bar, 6-bar
  3. DR4B
  4. Cascade
  5. Chainbar
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Overview of frequently used intakes

  1. Claw
  2. Side rollers
  3. Top roller
  4. Forklift
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Best Building practices (general)

  • bearings

  • screw joints

  • Types of nuts

    • Nylocks are heavier, but have much greater grip. They likely will not significantly loosen even after extensive use. Additionally, not tightening them (and allowing the screw to spin freely) is perfect for rotating joints.
    • Keps are lighter and are the quickest to use. Their teeth help maintain its position when tightened, but not as much as nylocks and cannot be rotated once tightened. Perfect for prototyping or securing less vital structure.
    • Plain nuts are the lightest and are used mostly on parts with places for the nuts designed onto them, such as the clamping shaft collar or V2 rack gears.
  • basic gear ratios

    • Builders can trade motor speed for motor torque (and vice versa) by using a system of gears to change the speed of the output shaft.
    • gears have a set number of teeth, and when gears mesh, the output gear rotates however many teeth the input rotated, not the number of rotations the shaft went through. Builders can use this to their advantage so that the output gear rotates faster, but with less torque (larger gear -> smaller gear), or slower but with increased torque (smaller gear -> larger gear).
    • If gear sizes become too extreme, more advanced builders may use compound gearing to exponentially modify their gear ratios. This is done by having the output shaft from previous gearing become the input shaft for more gearing with different gear sizes.
  • no cantilevered drive wheels

    • As a general rule, for anything on a shaft other than shaft collars and washers, the shaft should be secured to structure on both sides of whatever it is supporting.
    • Not doing this results in the shaft having a lot of wiggle room, as typically seen when wheels are exposed on the outside of a robot.
  • spacers, standoffs mounting

  • use all omni drive base with 4 motors

DR4B Tutorial by 333A

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Other important build topics and examples

TBD General

  • Geartrains
  • Chaindrives

VEX Reference Build instructions for starter kits

Tower Takeover Season Specific

Theory:

Physics of Tilter
How To Fix Intake Compression [Guide]

Showcase Tilters:

448X, 21S, 6671X, and 1437Z RI3D Reveal
1961Z Tower Takeover Teaser: Mk. III
42700N Summer Reveal
25461Z early season reveal: https://youtu.be/Wvz_8Ja-JQw

Showcase DR4Bs:

97963A Early Season Reveal
Robot in 3 Days Reveal: Houdini | 9605A + 9421
VEX Tower Takeover 21000C 66 Point Driver Skills (Robo Bonanza @ Beckman)

Showcase Wallbots:

2019 NorCal RI3D Reveal

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Programming environments, links to help and tutorials

https://www.learncpp.com
https://www.tutorialspoint.com/cprogramming/index.htm

V5:

Cortex:

TBD: Supported languages, platforms, blocks vs text, which one to choose…

API Reference:

Tutorials

LVGL:

For pre-V5 (Cortex) hardware:

https://www.robotc.net/wikiarchive/Tutorials/Getting_Started/Getting_Started_with_the_VEX_CORTEX

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Programming: Getting Started with VEXcode

  • Motor config
  • Sensor config
  • Competition template

VEXcode, motor groups and drivetrain example
VEXcode for experts

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Programming: Common Beginner Mistakes and FAQs

TBD

Note:

make process closed with exit code : 2 means ‘code could not compile, your code probably has errors’. When creating a thread for help, please attach the whole log with your code.

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V5 Architecture and Troubleshooting

V5 architecture diagram (may need to move to advanced topics): The PROS of PROS

V5 Troubleshooting:

Tips/warnings for v5?

  • V5 mini USB Port / use magnetic cable
  • V5 Motor inserts / be careful
  • V5 ports and static
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Engineering Design Process

https://www.google.com/search?q=engineering+design+process
TBD

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