991 Broncobotics | 2024 Build Thread | Open Alliance

Welcome to the Team 991 BroncoBotics Open Alliance build thread. This is our first year with Open Alliance and we are excited to join this community!

About Us:

BroncoBotics is a student-led team affiliated with Brophy College Preparatory in Phoenix, Arizona. We first competed in FRC in 2002. We compete in VEX (201A, 201B, 201D), FTC (201, 202, 23737), and FRC (991). We also mentor two VEXiQ teams (992A and 992B). This season, we have about 30 members on our FRC team, with 6 team leads (Mechanical, CAD, Code, Electrical, Manufacturing, and General).

We work out of our school makerspace (the Innovation Commons, or IC), where we have access to 3D printers, resin printers, laser cutters, a waterjet, a CNC, as well as various other machines/tools.

We are currently signed up to compete at the Las Vegas Regional and the Arizona Valley Regional.

Offseason Recap

During the offseason, we have competed in multiple offseason competitions. We competed in the Arizona Robotics League (ARL) series of events. We were on the winning alliance twice and had lots of fun getting some driver practice as well as meeting other AZ FRC teams.

Additionally, we competed in the Sanghi Foundation AZ FRC State Championship offseason event, where we finished ranked second in the qualifying rounds, and were the finalist alliance (shout-out 1165 and 2478).

We also started construction on a second chassis to use for driver practice (specifically at off-season events). The chassis is mechanically, but not electrically, finished.

We have also made a major push for part/tool organization in our workspace, specifically the room in our school’s makerspace dedicated to robotics. As you can probably imagine, when you compete in four different robotics leagues, it gets a little (very) messy very quickly. After a major push to organize and clean, it is currently in a much better condition and much more usable for the 60+ people who are using it. Additionally, we are looking into ways to keep the room organized, and not have to re-organize and clean every two weeks (any suggestions are welcome and appreciated!)

Additionally, we were happy to be featured on our local news channel (Arizona’s Family), where we brought our t-shirt cannon to their charity car wash. We got to show off our robots to the community as well as shoot our t-shirt cannon on the news live (clip can be found here.

We were also grateful to be sponsored by Axon, who invited us to their headquarters in Arizona, along with two other FRC teams. We had a great time getting to know some of the FIRST Corporate people who flew in, as well as the employees at Axon. We were able to get a tour of one of their manufacturing facilities, as well as drive their Ghost Robotics Vision60 robo-dog.

Lastly, after our last off-season competition, we had a post-season recap where we got our team together and discussed the ups and downs of the different aspects of our season. This was great, as we were able to document everything that was discussed, and can now take that information into consideration as we go into the 2024 Season.

We look forward to starting this year’s build season with you all, and wish everyone a funky year!

-Benjamin Kravets (BroncoBotics’ President)

Find us at broncobotics.org, Instagram, Github, Twitter (X???), Threads (better Twitter??), Bluesky (better Threads??), or Myspace


shameless plug: if you want a bluesky code for your frc team, 991 has some for you!!

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W for myspace

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We split our kick-off day into four parts:

  1. The kick-off event for our region
  2. Looking over the handbook thoroughly (at our school)
  3. Deciding what we want to do (e.g. goals, objectives, etc)
  4. Deciding how we want to do it (e.g. mechanisms).

Handbook Overview

Once our entire team read through the handbook, we noted important rule changes/additions, important aspects of gameplay, etc. It was at this time that we also analyzed the chart of possible ways to score points and started thinking about which ones we wanted to focus on. Below is a picture of all the rules/aspects of gameplay we found important/notable.

  • Carry one note at a time
  • 107 notes on the field total (53 each)
  • 90 in the source areas - 45 per source
  • 6 notes are on the Wing Spike Marks
  • 3 notes in each wing
  • 5 on center alliance spike marks
  • 1 preload per robot
  • Harmony is achieved if more than one robot is on the stage
  • Full surround bumper
  • 1 foot extension limit from perimeter
  • 120 in robot permitted maximum
  • 4 foot max-height
  • Melody - scoring at least 18 notes in the amp/speaker area
  • Harmony - hanging on the chain
  • Ensemble - gets RPs - needs two hangs and 10 stage points
  • amplification is 13 seconds
  • if spotlight, it only affects the robot below the spotlight
  • 1 Human Player per team - 2 total per alliance
    • Technicians can sub in for human players
  • cannot shoot into the wing from outside of the wing
    • can shoot from outside of wing to outside of wing
  • field is mirrored, not symmetrical
  • cannot tension, twist, or alter the chain
  • cooperation points must be obtained in the first 45 seconds of teleop
  • high notes can only be sent during endgame
  • amplification can happen multiple times
  • cooperation only uses 1 note
    • it also removes a note from amplification
  • cannot score high notes anywhere besides the spotlight

Deciding our goals

For us, this meant narrowing down the objectives that we wanted to complete in our match, as well as our goals whilst doing that (ex: we want to score in the SPEAKER and have a fast cycle time whilst doing it). We split this up by each section of gameplay - auto, tele-op, and endgame. Our analysis is below.


  • Pick up from the ground
  • Score in the AMP and or SPEAKER
  • Leave the WING
  • AprilTAG/Odometry
  • AutoPicker - selectable autos
  • Consistency


  • Hang off of the chain with somebody else
  • Score into the SPEAKER from most areas of the WING
  • Auto alignment with SPEAKER, SOURCE, and AMP
  • Low-profile pickup for picking up rings
  • Shoot scoring and place scoring - TRAP vs. SPEAKER
  • Fast cycle time
  • Be able to drop rings into the robot directly
  • Fast mechanisms
  • Be able to pick up rings at different angles
  • Be able to go under the stage
  • Strategy
    • Go for the Cooperation bonus
    • Small and light
    • Get notes under the speaker, then do amplification


  • Hang
  • Score into the trap
  • Score the high note
  • Consistency with the human player
  • Hang at an angle
  • Hang at any point on the chain

Design Choices

To start thinking about design, we split into smaller groups to focus on the three main areas of the design - intake, outtake, and hanging. Each group mind-mapped ideas for each mechanism and then presented them to the group. Below is an example of one of the mindmaps, as well as the list of all the ideas for each mechanism.

Group 1 - Intake

  • Chute - direct intake from the source and the ground
  • Ground intake - The robot drives over the disk, elevator brings the disk into the robot
  • Over-the-bumper intake
    • Arm (1/2 joint) with claw
    • Conveyor Belt
    • Pan-like pickup to score TRAP/AMP (like a dustpan)
  • A belt system that picks up disks when they are driven over
  • Use flywheels to pull over the bumper
  • Have the intake be a shooter then angle down to pick up the disk, then angle up to shoot
  • Have the Human Player drop disks straight into the shooting/outtake chamber
  • Funnel to a claw-thing

Group 2 - Outtake

  • Slingshot
    • Pneumatics/springs/elastic
  • Flywheel
  • Catapult into the amp
  • Ramp into AMP
  • Arm with claw

Group 3 - Hang

  • Drive up the chain
  • Telescoping rod
  • Winch robot up via the chain
  • Carabiner to attach to the chain
  • Clamp onto the chain
  • Multiple arms to adjust COG
  • Buddy climbs
  • Dual outtake/climb mechanism
  • zipline traversal
  • push the entire robot up

Current Design Decision

In the end, we decided that our main goals were to be small and fast. To accomplish this, we decided to:

Intake - A ground intake under the bumpers that funnels into our outtake; can intake on three sides

Outtake - A tray with flywheels that will suck in Notes from the intake and then shoot out at a variable angle; the outtake is also capable of having Notes dropped straight into it from The Sources.

Hang - two telescoping poles with clamps on the ends that clamp onto the chain then retract to lift the robot.

Here is a sketch of our design. Better drawings/pictures to come in future updates



Just a quick CAD update - here are a few pictures of our CAD. We have ordered parts and will update with build pictures as soon as we have them.



(the outtake wheels are not in the CAD yet)

robot :+1:

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Since our last post, we have finished our CAD and started building our chassis superstructure. We have also finished building our field elements and continued to build prototypes of our intake and outtake.

We’re going to break this up into subsystems:


We’re using mk4i falcon swerve, and we just created these swerve drive covers using our Bambu Labs X1C and its AMS.


We have an under-the-bumper intake based on sushi roller wheels. Our prototypes worked pretty well for this design, so we’re pretty confident in creating this out of real materials soon.


(we did not take any videos or photos of our prototyping process, sorry)


We have a pivot outtake with horizontal flywheels as our outtake. Again our prototyping worked out pretty well. We attached what remains of our outtake prototype (again, no videos or photos of the process :skull:)



We (mostly me) are kind of behind on our software development process. Our constants so far are Java, advantagekit/advantagescope, a limelight, and pathplanner (maybe with Choreo). We’re going to be working on Note detection using Google Coral and hopefully a custom dashboard using FRC web components.

Some other photos:


These covers look awesome! Do you have a public link to your Onshape?

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our onshape document is here! Our covers are these, and one of our team members created the numbering for it.


Not sure if this is an issue on my end, but the link to the onshape doc isn’t working. Can you maybe update it? Thank you!! (Good work so far btw)

I just fixed the link – sorry about that!

Quick Cad/Build update for you all

Here is an updated screenshot of our CAD (available here). We finished CADing a lot of the smaller details that we did not do upfront.

We plan to post build pictures sometime this week. We are attending Duel in the Desert in Arizona on 2/24/24.

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Hello everyone! We have been hard at work polishing our robot for the Arizona Valley Regional competition this week. We’ve got a few pictures of our robot for you all! Next post will be after comp this week.


Hey everyone!!!

We just finished day one at the Arizona Valley Regional (where team 1165 made fun of our lack of posting).

We’ve been troubleshooting a ton of issues - here’s a quick list:

  1. Our bumpers were a bit goofy (we totally didn’t bring it to someone’s house to fix at 11pm last night (with a Home Depot run where we got questioning looks from the employees when we walking in with both sets of bumpers looking for rivets and screws)).
  2. Limelight tuning issues (thanks to frc 4415 for the help!)
  3. Our hang strings snapping (thanks to 1165 for extra paracord)
  4. Our swerve CANCoders not resetting their zeroes well (we’re resetting wheels on the field now).
  5. completely redoing our auto aiming code
  6. our outtake not being in frame perimeter (do NOT ask how we fixed this)
  7. completely reworking our operator controls

Other than that, we’ve been practicing impact award & dean’s list presentations, scouting in the pits, and getting a lot of driver practice in. We had a great time talking to new teams and meeting new people. Overall, it’s been a great day one!


Reach out if you’re still having issues!

Hey everyone!

It’s been a few days since the end of AZ Valley! It was a hard comp for us – we had a ton of issues that should all be resolved for the Vegas regional next week!

Things we’ve been working on:

  1. Fixed our bumpers after they sustained some damage
  2. Fixed our CANcoders on our MK4i Swerve Modules so that we don’t have to zero our wheels before every match
  3. Autonomous testing – we’re switching from Pathplanner to Choreo + Pathplanner to hopefully get our autons as good as we can make them.
  4. Re-manufactured and reattached our pivot motor mount
    4i. We sustained some large hits during matches at AZ Valley and noticed the chain was at a bad angle, so we moved the pivot motor mount over 1 inch to fix this issue
  5. Getting more driver practice in
  6. Re-packing our pit supplies for Vegas to make sure we have everything that we need
  7. Training more scouts to be ready for Vegas

If you are at the Vegas Regional this week, come say hi! We’d love to talk!