Spectrum 2019 Resource Collection

Every year we try to document a little bit more of our knowledge and procedures for other teams to use and benefit from. This year we have released a varieties of guides that teams can learn from. We have collected them all here so you can see them in one place.

Protopipe - Blog Post - Documentation - CAD Files

Protopipe is a system of 3D printed parts that allow you to easily connect 1/2" PVC pipe into robot mechanisms and test fixtures. It's designed to be cheap and easy to use so that teams can iterate their designs faster. Several teams have been printing out the connectors and testing the system this off-season and we have gotten some positive feedback. There is still room for improvement but we think it will help us and other teams develop better systems this season.

Guide to the FRC MCC

We have been asked a lot about which parts teams should buy before the season. That's a really hard questions because you need to know the goals of the team. So in this document we outline the concept of a Minimum Competitive Concept Robot, give examples of teams that successfully build MCCs, and also a list of items that we would use to build an MCC. If you are just starting out or have limited resources these are the robots you should view as your inspiration. 

FIRST Choice and Voucher Recommendations

We made a list of our recommended items to use your Vouchers and FIRST Choice credits to subliment your KOP.

Spectrum-Photon LED Animation Driver - Documentation - GitHub

Simple addressable LED control for FRC robots. This uses mostly COTS electronics and software to allow teams to add addressable LEDs to their robot and control them easily from a RoboRIO. This allows teams give feedback to their drivers using the LED strands or rings placed on their robot. Animations are handled on the microprocessor with the RoboRIO just sending simple serial messages to choose animations, colors, and other details.

Advanced Pneumatics Guide

We have gotten a lot of questions about our pneumatic system from our 2018 robot. We made some quick notes about the techniques we used to get a small and light system and also how we were able to use pneumatics to launch the cube. There are also some suggestions from other teams, special thanks to FRC#5406 for helping out with suggestions and edits.

Powder Coating Guide - PDF

This guide gives you a quick overview of the equipment and process we use to powder coat our parts for our robots. We have been doing this for 2 years now and spoke to several teams before starting to do it ourselves. The process isn't that complicated and you don't need to buy or build a large oven to be able to do most of the parts you need on an FRC robot.

Spectrum Recommended Software

A quick list of the most common software we use on Spectrum. There are alternatives to all of these but these are what we found works for us. 

Printable 500 Hex Collar 

Useful little printable hex collar. Great for load load applications and prototypes. Same thickness as a VEXpro Hex collar.

2018 3847 Robot CAD

CAD of our 2018 robot Infrared. Solidworks and Step file.

Updated FIRST $1000

We did a quick update to our FIRST $1000 list to make sure all the products were available to teams.

Spectrum 2018 Resource Collection

Here is the list of resources we released before last season, lots of that information is still useful today. 

- Spectrum

"You get a new year, you get a new start, you get a new opportunity." - Billy Butler

90 degree adapter prototype

We purchased a Milescraft 1303 Drive90PLUS right angle drill adapter from Amazon to see if it would work as a 90-degree adapter for FRC applications.

This FRC#33 instructable inspired us to look at other adapters.

The Milescraft adapter is slightly more compact than the DeWalt, and it uses bearings instead of bushings.

We unscrewed the main handle form the miter gearbox and pulled the snap rings to get to the internals of the mechanism. They appear to be sintered gears which are weak under impact, but for many FRC applications, this should be acceptable. There aren't any thrust bearings in this device so you shouldn't be pushing against either in the input or output features either.

 This is the main assembly with the bearings held in with internal snap things.

Here is one of the gears and bearing pulled from the housing.  

Here is a picture of both of the gears and one of the bearings.

Here we drilled a hole in through the input side of the housing to allow for perpendicular outputs. 

Here is the final output with a 1/4" hex shaft going all the way through the input.

Also in this photo is a 1/2" hex tube with 1/4" hex internal bore from McMaster.

You would likely need to 1/4" hex broach the output of a gearbox for this to work in many applications but some application may only need hex to hex on both ends, and the McMaster tube can be used in those applications. 

We haven't used this on a robot yet, but it's a useful tool to have in your design toolbox.

- Spectrum

What we bought - Fall 2018

A lot of teams ask us where we buy stuff, so occasionally we'll just post about the things we bought and where to get it. 

Amazon

• Snap Ring Groove Cutters .043" - These are for cutting heavy duty snap rings on 1/2" shafts or regular snap rings on 3/4" shafts
• 4 AWG Wire - New Battery wire, flexible 4 AWG.
• White and Black 12AWG Silicone Wire -  Similar to what comes pre-installed on Talon SRX speed controllers. This is our go to wire for motors.
• Allen Wrench Folding Set - Very useful during the season and reasonably priced.
• Gallon of cutting fluid - Used in our horizontal bandsaw we also have some squirt bottles with a very diluted mixture in them for other cutting and drilling tasks. The gallon container will last you multiple seasons.
• Bob Smith 103 Super Glue - This is really good super glue
• Cheap Needle File Set - great for fixing up 3d printed parts, or getting into hard to reach places
• Double Stick Polyimide Tape - Used for sticking 3d printed build plates your heated bed
• Nice 3D print removal tools - We have a couple $1 store paint scrapers that work okay but these are better but cost more.

McMaster.com

• 1/2" Snap Rings
• 9/16" Snap Rings - Useful for going on hex shaft without first turning it down to 1/2"
• Tubing Connector for 7/8" tube - 7/8" aluminum tube is a similar OD to 1/2" PVC so we can use it for stronger Protopipe mechanisms.
• 5/16" O-Ring - These can go over 1/2" thunderhex shaft and work similar to VEX IQ rubber shaft collars. This is useful for quick prototypes or places where you might need to adjust often or you just don't have shaft collars. 
• 1/2" OD - 1/4" ID Aluminum Hex Tube - This is 6061 hex shaft that for us at least came in slightly undersized so it fits in bearings and hubs easily. It also comes with a 1/4" hex hole so you can you it as a spacer for 1/4" bolts or an adapter down to 1/4" hex if you need to make a small mechanism. The 3/4" to 1/2" is also useful if you need a bigger hex profile.
• High Flow Solenoids 1.0 CV - These are the high flow solenoids that we used on our 2018 cube launcher mechanism

Zoro.com 

• Tstack Big Drawer - Stackable tool boxes that we use at events
• Tstack Double Drawer
• Tstack Large Top Box
• PETG Sheets 2'x2'  - 1'x2' - PETG is a great plastic for the laser cutter, it's 70-75% the strength of Polycarbonate but a lot cheaper and works with the laser cutter much better.
• Acetal Sheet 1'x2' - Acetal (or Delrin) is an engineering grade plastic that cuts very cleanly on a laser cutter.
  

This is just a sample of the items we purchase, hopefully this will give you an idea of some of the things you can buy to help your FRC team.

- Spectrum

Guide to the FRC MCC

We have been asked multiple times to put together a list of items teams should have on hand to build their robot. That is a hard question to answer because there are so many different goals and build methods for FRC teams and robots.

We decided to approach this problem by thinking about an average team trying to build a competitive robot with a limited budget a few tools (possibly the list of tools from 1000.Spectrum3847.org). From there the goal is to figure out what that robot would look like and what items do teams building it need.

We decided that the concept of the Minimum Competitive Concept (MCC) perfectly fit the goals of the team we were imagining. MCC is a concept first put forward by Isaac Rife, IKE on CD in 2012. Isaac describes the challenge of the MCC as such "It is often easy to identify all the possible tasks you could have a robot do. Prioritizing those tasks, and realizing it in the form of a competitive robot is in my opinion much more impressive. Assumptions are that one of the primary goals of the MCC is to play in elims (not necessarily win on Einstein), and you team has mid-pack to lower fabrication resources."

We identified examples of MCC robots from the past and found qualifies that they all shared. We then looked through the wide array of possible build items and techniques to find the most useful for teams on a limited budget and with limited fabrication resources.

Our complete guide can be found on CD or at 

MCC.Spectrum3847.org

Please let us know what you think.

- Spectrum

FRC Powder Coating Guide

We have released a Powder Coating Guide for FRC teams. It shows you how we powder coat our parts in our lab and all the equipment you need to do the same.

Download it from Chiefdelphi here.
https://www.chiefdelphi.com/media/papers/3511?

Protopipe: Rapid Prototyping System

We have been working on creating a system to allow us to quickly and easily design mechanisms that let us solve the problems given to us in the FIRST Robotics Competition. This past season our prototypes worked well but they took a long time to modify and adjust and that led to our design process taking more time than we would want.

We listed some goals for the system.

Goals

• Rapid iteration
• Easy to remove and add parts
• Easy to reuse parts in the next prototype if needed
• Inexpensive
• Try to avoid using expensive parts such as bearings, etc.
• Use a cheap base material that is locally available
• Easy adjustment
• Clamp systems for small adjustments of spacing and belt and chain tensioning
• As few unique parts as possible in the generic system
• Easy to make custom parts for each unique application if needed.
• Able to quickly make rotating parts such as intakes, ball paths, etc.
• Powered by a hand drill or by a Versaplanetary (or 57 Sport if you like)
• Able to quickly attach to pneumatic cylinders for making wrists, small arms, catapults, etc.
• Able to make a rough linear slide system for prototyping stackers / elevators (2015)
  

Basic System Explanation

We decided on using 1/2" PVC pipe and 3D printed connectors. 1/2" PVC is widely available at most home improvement stores for very little cost (a few dollars for 10 ft lengths). 3D printers are becoming very common among FRC teams and the filament is getting much cheaper as well ( <$20 / kilogram). So these parts seem like they would work well. 

The connectors allow you to connect the pipe to flat parts as well as hold 1.125" bearings for making systems with hex shafts, etc. To connect the pipes to the connectors you can either use short self-drilling screws or hose clamps to clamp them on. The clamps allow you to easily adjust certain parts to move items and figure out the best measurements for your system.

The full system is described in the google doc explanation here.

Link: Full System Explanation, Examples, and Notes

CAD Files

We have uploaded all of the Solidworks part files, STLs, and STEP files for the different parts as well as a few STEP files of the example prototype/bench tests that we have designed. 

Link: CAD Files

Examples of the System

FIRST Choice and KOP Vouchers

The Kit of Parts (Collection of Parts?) includes a lot more than just the totes each team receives on Kickoff.

The FIRST Choice system and KOP vouchers allow teams to have the flexibility to choose what they get from a wide selection of options. This can often be very daunting for new teams.

We've put together a list of items for FIRST Choice and your vouchers that we recommend teams selecting. You don't have follow are recommendations but it should give you a starting point if you are struggling to figure everything out.

We want to thank Andrew Hartnett and Pearadox FRC#5414 for putting together the full spreadsheet of FIRST Choice items and figuring out a lot of the items value.

The full document can be viewed here and it will be updated as the season goes on. We have also embedded it below.