FRC 3481 Bronc Botz 2023 Build Thread

Welcome to the 3481 Bronc Botz 2023 build thread, presented by #openalliance.

About 3481 Bronc Botz

Bronc Botz is a FIRST team out of San Antonio, TX located at Louis D. Brandeis High School. We strive to teach our students core STEM knowledge that can advance them in the workforce like team work, CAD, and safety among others. We instill cooperation and gracious professionalism in our students.

We’re working to build the FIRST community in San Antonio & South Texas through partnerships with other FRC teams, FTC teams, and school districts who are advancing FLL and FTC programs. We also work with a variety of community organizations to advance STEM Education and FIRST to San Antonio students.

We made the decision to join the Open Alliance after the close of the 2022 FRC season, and have spent the summer and off-season working on a ton of projects. These projects have included revamping parts of our pit, purchasing and programming a swerve drive, and working toward developing more sustainable training resources! We’ve worked hard to prepare for this next season. Truly amazing to see so many teams supporting the Open Alliance this season and starting their own build thread.

Competitive Goal for 2023

Our goal is to be one of the top 4 alliance captains at district qualifier events, and to be in elimination matches at district champs. We’ll be playing at Belton week 2 and San Antonio week 3.

We’re excited for 2023 and love to share it with you all! Stay tuned for updates on our ongoing projects!

If you have any questions, feel free to ask them in the thread, through DMs or on Discord.


Maybe we could have an openalliance alliance in Belton, looking forwards to it!


11/30: T-Minus 38 Days until kickoff

During the off-season, we have begun a number of projects to strengthen our team, the first of which was redesigning our battery cart (which we’ve been using for close to 7 years now).

Our old design can be seen here -

There’s a couple key issues with this design-

  1. The base is wide, however the actual box is slim, making the base a tripping/shin hazard in the pit.
  2. The cart is tall, making it top-heavy
  3. There are no additional uses (ex. storage), as the bottom is sealed with plywood.

We tackled these issues by making these edits-

  1. The base is wider (5ftx1.5ft, appx the size of of a rolling toolbox), and will not have any protrusions
  2. The cart will be 4ft tall (appx the height of a rolling toolbox), which will make it less top-heavy
  3. There will be open storage at the bottom of the cart, additional battery charging stations (enough for 14 chargers instead of 8), lexan and stock storage locations, and will have a work-top for additional workspace in the pit and shop.
  4. There will be a plastic cover over it without team name and number etched into the side.

Here is the CAD model of the updated design -

Another project we have been working on is a new way to store and transport our black and orange organizer boxes. The boxes are essential and useful as they provide us a way to organize all of our parts such as spacers and hubs, but can be a hassle to transport. Another issue we run into is that when the organizers are stacked, we always seem to need the box at the bottom of the stack. To solve these issues, we designed a storage cart where each box can slide into a designated slot. The cart is built in a dolly-like fashion to make it easy to transport at competitions. Below are images of the black boxes and the CAD of the new storage design.

The third project in progress, continuing on the theme of new carts, is a new robot cart for competitions. Currently, our robot cart at competitions consists of a dolly with a wooden structure mounted on top to bring the robot from pits to the field. It was conveniently portable but visually unappealing, and not the most stable. If placed incorrectly the robot would easily tip. To solve these issues and get some more CAD practice before the season, we designed a new robot cart in Onshape to be machined out of plastic (HDPE). This new cart would be modular to be easily stored in our shop, and to be more sturdy when transporting the robot during competitions. A prototype of this design can be seen below.


Apologies for the delay! More information about Week 1 to come very soon!

Kickoff Summary

We have a specific method for running our kickoff. We start with a full manual read (which can take over an hour) to make sure that we fully understand the subtle nuances of the game. Some points of interest this was the scoring breakdown of the activation bonus and not being able to extend in two directions.


A Need/Want/Dream chart is a tool we use to set goals for the season. Need is what we believe is the bare minimum for competing. Want is what we generally design for — a robot designed to the want standard can typically perform all functions of the game adequately, and is where our team always strives to be. Dream is what the world-winning teams will be doing, and in our terms, can generally be achieved with good programming and drive-practice. You can view our Need/Want/Dream chart below.

After completing our Need/Want/Dream chart, we decided on subsystems for this season’s robot. We settled on 3 primary subsystems, with a couple smaller subsystems that we may expand on later.

Subsystem 1: Drive Train

  • After lengthy discussion, we decided that swerve is a non-negotiable. We spent the off-season (since September) working on it, and have decided that perfecting swerve during season is worth taking less time on other programming projects.
  • We have decided that we will likely be bottom mounting the SDS MK4 modules (mounting the plates on the bottom of the 2x1) in order to have more clearance for the ramp. Because we have not done this before, any feedback on this idea would be appreciated!

Subsystem 2: Lift

  • We had thrown a couple ideas on the table; a slanted elevator with a horizontal slide, a regular elevator with a horizontal slide, and a four-bar lift
  • After discussing pros and cons, we decided on continuing with a vertical elevator coupled with a horizontal slide mechanism.

Subsystem 3: Intake/Scoring Mechanism

  • After watching some Ri3D streams and videos, and looking back at previous games and robots, we had settled on a general intake similar to the 2018 cube scoring mechanisms. The decision was between a passive stretch or a powered (likely pneumatic) intake size change (stinging in and out).
  • After some prototyping, we decided on a passive intake design. We have set a goal to have the first draft of the CAD completed by Thursday, so that we can CNC the first draft and run more realistic tests.

Relevant Links


CAD is looking wild! Love it. Keep up the good work.


Looking forward to being at Belton with yall. Good stuff so far