Spectrum 3847 - Build Blog 2021

With the bulk of our FRC at Home challenge work completed, we have begun work on designing a new robot for 2021 off-season events: Gamma Ray 2021. It is still in the early stages of its design, but we wanted to allow people to follow its progress.

OnShape Public Link

Photo & Slide Gallery


  1. In the fall of 2020, we decided to register a 2nd FRC team at our schools, Photon FRC#8515. This team will be the “Development Team” for Spectrum. The general plan is new students will be on Photon but will also be members of Spectrum at the same time.
  2. The plan is for this new robot to compete under the banner of Photon at The Texas Cup event.
  3. We have been kicking around the ideas for this robot since March 2020, but the actual CAD didn’t get started until last week. We didn’t build or modify our 2020 robot for the skills challenges; we just used it as is.
  4. Spectrum has switched from Solidworks to OnShape, so it will be easier for anyone to view the robot’s progress.
  5. Most of the build blog updates for this will be the design slides our team uses to organize our thoughts and keep everyone updated. The full design slide set will be uploaded to our photo gallery.
  6. One of the major goals of this robot was to design and build a full swerve robot before the 2022 season. If you haven’t heard, there will likely be a lot of new swerve teams in 2022.

  • Spectrum

I really appreciate the work y’all do when sharing with the community! I can’t wait to see this come together and to compete with Spectrum and Photon at The Texas Cup!


What are you using to couple the servo to the shaft it drives?

I assume you are talking about the image on the launcher slide, correct?

That isn’t our CAD model that is an image of 2102’s launcher. I can answer the question though, they have a small 3D printed adapter from the servo horn to the hex shaft.

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Week 2:


Spectrum was recognized as one of the FIRST in Texas District Chairman’s Award teams. We had one of our students from 3847 and one of our students from 8515 advance to the District Champions Dean’s List round.

Congratulations to all the teams

Subsystem Updates

OnShape Feature Scripts

Here are some of the feature scripts we have been using on this robot to help us generate parts faster.

Laser Joint

  • Creates the finger joints that we often use with laser cut parts
  • Video

T-Slot Joint

Advanced Gear

  • Creates Spur, Helix, and Double Helix gears

Shaped Flange

  • Allows you to make a flange from a sketch profile, and can also offset the flange easily so you can make “Bend Outside” parts nicely.