Friday, January 31, 2020

2020 Day 28: Tower Rails & Feeder Station

Tower Rails

We have our tower rails mounted in place on the protobot. Tomorrow it will get shafts, belts, shooter wheels, & motors. We will also add a basic electrical system to this robot to test it. The protobot won't have a full climber but we will use it to fit test many of the climber and buddy climb parts.

Feeder Station

We briefly tested how balls will fall into our robot from the feeder station. We are considering adding another bar and some thin lexan to the top of the intake to prevent balls from ball down near the intake rollers instead of into our funnel.


2020 Day 27:Tipping Point

Today marks the midway point between kickoff and our first event week 1 in Dripping Springs.

Intake and Indexer Testing

Both systems are working as expected. More videos are in our photo gallery. Our plan is to only hold 2-3 balls in the funnel and let 2-3 balls be in our tower as well. But we did want to test what happens if we human load or just don't sequence everything properly.

Here is a cut of way of how we hope to be able to hold balls
Ball Path Cross Section View.PNG

Sheet Metal

We have sent off the CAD and drawing files to our sheet metal sponsor for our competition and practice robots as well as some parts for the elevator. Most of the other subsystems will be iterated in house until we get closer to final parts ready for sheet metal. That may not even be till after our first competition. 


Wednesday, January 29, 2020

2020 Day 26: Intake progress and motor allocations

Intake Progress

Progress on the Protobot intake and funnel have come to their 2nd iteration.

This version fixes some geometry issues with the first and removes the belt path from the center of the funnel.

Motor Allocations

We added our motor allocations to our copy of the Spectrum Design Sheet (
Motor PDP Allocations.PNG

CAN IDs were also assigned in the sheet

PCM slots were assigned as well


Monday, January 27, 2020

2020 Day 24: CAD Update & Vision Update

CAD Updated

The STEP file on GrabCAD has been updated for this week. You can download it here -

Vision Progress

We have made a lot of progress using opensight to be able to track balls and track the rectangle on the loading bay. We are planning to use a limelight for aiming our robot and to have two additional cameras for driver viewing and tracking of balls and the loading bay.

Ball tracking is using a color filter and then selecting only circles.

The rectangle tracking is just normal shape tracking on the retro-reflective tape.


Sunday, January 26, 2020

2020 Day 23: Intakes and Drive Trains

Falcon Pinions

We ran into our first issue with the Falcon 500s are second batch of pinions were a tight fit on the falcon shafts which is a known issue and is discussed in that thread. We used a wire wheel brush similar to ones in this kit. It took some of the nice black finish off the front of the falcon with it but it worked to take the shaft OD down enough to get a nice slip fit for pinions. We noticed that most of the pinions prefer to go on to the shafts a certain side first. When slipped on to the shaft the other direction they seem to stop sooner but when you turn them around they slip all the way down after the wire wheel.

Protobot Progress

Our protobot intake, indexer, and drive train are coming along.


Small incremental improvement are on the way, which is why we are doing it on a full prototype robot. So we can drive it and make changes for the comp robot to handle the balls better.


Saturday, January 25, 2020

2020 Day 22: Protobot Chassis & Purchases

Protobot Chassis


We found some issues with the current design that we will be fixing before we send off the comp bot and practice bot chassis. 


Here are some of the items 3847 has purchased this season from some non-FRC suppliers.

Belts from
We started using them in 2018 and haven't looked back. Their timing belts are cheaper than every other source we have found and they have nearly every length and width you could want. Combined with 3D printed pulleys these have made there way on to many parts of our robots over the past few seasons.

A 70 tooth, 5mm pitch, 9mm wide HTD belt is 350-5M-09. The 350 is the belt circumference which is tooth count multiplied by pitch.

USB Wide Angle Camera
We have been using this camera for a couple seasons as well. The wide angle lets you see a much larger portion of the field while driving. - ELP 170degree Fisheye Wide Angle VGA USB Camera
Cheap PTFE Sheet
This is way cheaper than the comparable product from McMaster and from our brief testing seems as slippery on the ball as the McMaster stuff. It's possible it's not pure PTFE but it's what we are planning to use on our robot. PTFE Film No Adhesive, Pure White 16 x 60 inch

PLA Pro Filament
We have been using this filament extensively this season. It has all of the benefits of PLA, fast print speeds, stiffness, and inexpensive but it's far less brittle than normal PLA and stronger. There are still times for even stronger and tougher filaments but for general printing this is our new default material. DURAMIC 3D Premium PLA Pro Printer Filament 1.75mm

Friday, January 24, 2020

2020 Day 21: First Sheet Metal Arrived & Everybot Tips

Sheet Metal Arrived

With stop build day no longer existing this year we decided to move to a slightly different model. In most seasons we would build our practice bot and competition bot about a week behind each other. When we would do a sheet metal order we would order enough for two+ robots. This year we are building a protobot, a competition robot, and a practice robot. The drive train sheet metal for the prototype robot arrived today. After the get the protobot working nicely and test fitted we will release the rest of the sheet order to our sponsor to build the competition and practice robots. The practice robot will be completed after the competition this season. The protobot will also be decommissioned to create the practice robot. This is to ensure that our practice and competition robots can be closer to identical.

We are also making a larger portion of our robot our of extrusion than we have done in the past few years. 

Everybot Updates


Our Everybot project is moving along. We have the KOP chassis completed to the proper size and have begun cutting down some of the stock to make the Everybot.

We have found a cheaper source for the flex ratcheting wrench used on the Everybot climber. If you have a Grainger near you, you can order it and pick up in the store with no shipping charges.

We also have been using our bench shear and aviation snips to cut the tie plates into gussets instead of a band saw. We find this to be faster and easier.


Thursday, January 23, 2020

2020 Day 20: CAD updates

Largely we have been getting more of our subsystem designs CADed.

Shooter Design

Shooter Cad.PNG
We are experimenting with adding a rear kicker wheel to the shooter setup. The idea being to have more linear acceleration into the shooter wheel and less spin. It would be powered off the front accelerator wheel using polycord in a figure 8.

We have learned to use Solidworks surfaces to allow us to CAD a curved shooter hood and then unwrap it so we can easily laser cut it from a flat piece of material.

hood flat pattern.PNG


The Powered V funnel (based on FRC#6135's design), is moving along. We will have custom printed pulleys on 7/8" dead axles with 30mm wide, 5mm pitch timing belts to move the balls along. The BAG motors will be replaced by NEO550s in the real robot.

Full V.PNG

Climbing Brake

Last year we intended to use a VP ratchet slice to hold our robot after the match, but the standard ratchet slice never really worked. We ended up using a pneumatic cylinder driving into the ratchet adapter. We may be using a similar mechanism again this year.

Ratchet Isometric.JPG


Wednesday, January 22, 2020

FRC 2020 Youtube Channels and Vlogs

There are a large amount of teams that post vlogs and prototype videos to youtube that don't get seen by many people unless they are looking for them.

Several members of Spectrum have collected a bunch of these channels but we'd love to have more.
Full Sheet: Submit New Channels:


Tuesday, January 21, 2020

2020 Day 18: Design Review #3

Design Review #3

Third Tuesday of the season means it's our third design review.

Here are a few of the slides presented to the team by the subsystem leads today.
Design Review #3 1.PNG
Design Review #3 2.PNG
Design Review #3 3.PNG
Design Review #3 4.PNG
Design Review #3 5.PNG

Controls Update

More work has been done of the ball tracking using OpenSight.


Monday, January 20, 2020

2020 Day 17: Public CAD Release

CAD Updates

Today we finally reached a point with multiple systems to create our top level Solidworks assembly and add in the subsystems.

CAD Feature Tree.PNG

There are still a few subsystems to add but we are now working with most of the subsystems in one place with them mated in space. None of the subsystems are complete but each of the sub-teams is working on getting closer to real models for every part.

CAD 1-20 1.PNG

Public STEP File

We have published a STEP file of our current progress on GrabCAD. Remember that none of this robot is actually built and much of it is still in development so we don't recommend anyone using this design directly but we happily encourage teams to take inspiration from our progress and make versions of your own based on our CAD. 

We plan to upload a new STEP about once a week through out the rest of the season. If you haven't seen it updated in a while feel free to message us and we will try to get a new one made when we can.

CAD 1-20 4.PNG


2020 Day 16: Drive Gearboxes and Shooter Testing

Shooter Testing

We did more shooter testing today. We made several changes all at once we normally try not to do but circumstances were somewhat beyond our control. The modified VEX traction tire we had been shooting with had a failure and one of the tires broke apart. We won't be using that wheel anymore for our development of competition. It's possible it was just our implementation but we will be going with a solid wheel from here on out. We moved to 2x 6x1.5" colsons wheels we had from our 2015 drive train. 

We also changed the gearing to move the NEOs to 1:1.5 with a 36 tooth pulley on the NEO output and a 24t on the shooter wheel. We did some tests with the accelerator wheel on it's own NEO and then moved to a setup that had the 4" accelerator wheel ganged together with the colson shooter wheels 1:1 and only shot using 2 NEOs. The smaller diameter means that the 4" wheel will have a reduced surface speed. 

We also tested our shooter with a new backing of yoga mat foam and Teflon sheet. This backing still couldn't let us nicely shoot ball #14 (a ball that has previously been sliced open multiple times in a belt prototype). Once the balls have enough cuts, rips, tares, and holes to vent at a similar rate to a new ball they become very hard to shoot.
Here is one of our tests. The one ball that lands short is the ball that has multiple cuts through the skin. It compresses far easier than the other balls and the yoga foam doesn't seem to help.

After we adjusted the angle we were able to start hitting the 3 point inner goal from approximately the initiation line.

Drive Gearbox

The test fit of our drive gearboxes was done today. The competition versions will be 1/4" Aluminum plate but we can make sure everything working out of delrin or polycarbonate on our laser cutter. We are using a gearbox design inspired from this thread by Evan Morrison. Our implementation isn't direct drive so we can simplify some things as we don't need as much reduction. The 32:12 chain reduction to the wheels will get us a large part of each gears overall reduction. The spacers are 7/8" round tube with 3D printed inserts.


Block Robot Update

More of the design is starting to take shape. 
Block CAD Robot 1-19 3.PNG
Block CAD Robot 1-19 2.PNG
Block CAD Robot 1-19.PNG

Everybot Documentation is out

The awesome people behind Everybot have released this year's build guide and a brand new website. If your team is struggling to figure out what to build, building a robot based on the Everybot is a great idea. This robot will be effective in the 2020 FRC game for a large number of teams, definitely think about if your team should be one of them, it's a really good idea. Maybe you have another idea for a ball mechanism but just want to use their climbing mechanism, that works too. No matter what reading through their documentation will make you better at building robots and give you new ideas.


Sunday, January 19, 2020

2020 Day 15: Some progress

Shooter Hood

Tomorrow we will be testing some new shooter hood additions. We have yoga mat foam and PTFE sheet mounted to the hood.


Belt Tower Testing

We built a belt tower testing rig out of prototype so we can see how the balls react to each other and try to learn to prevent jamming mechanically in addition to control solutions that will come later.


Opensight was setup today to stream two driver cameras to the driver station and was using less than 3Mbps to do so. The controls team also looked into some edge detection as well.