1678 Citrus Circuits 2019 CAD Release

1678 is proud to release the CAD for its 2019 robot, Buzz Lime-Year! This robot won the Central Valley, Sacramento, and Aerospace Valley Regionals, and went on to become Carver Division Champions at the Houston Championship. Buzz Lime-Year features many 3D printed parts using our markforged and prusa printers, vision with limelights, the only successful triple HAB 3 climb system in the world, and more.

The link to the Onshape document containing our 2019 robot CAD can be found here.

This year was our first using OnShape, and after a lot of trial and error we learned a lot about the system. Feel free to ask us any questions about our experience with the software so far.

As always, we are happy to answer any questions threaded below, or emailed to us at [email protected] or [email protected] with hardware/mechanical or general team related questions respectively.


You mean it didn’t work the first time?!

Awesome resource and thanks for sharing.


Love the robot this year - I noticed you’re using round tube on your wrist but I can’t see how you connect it to the plates it’s mounted to. Do you use some sort of plug?

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Thank you! We use tube connecting nuts from mcmaster that push into the tube and have a threaded inner part, allowing us to send a bolt throught the outside plates. Here’s the part link: https://www.mcmaster.com/94290A550


Nice robot! Is this part to tension the rope?

This is amazing… thank you for sharing… Now to spend the next hour trying to figure out how everything works

Yes, that is correct. The looped bolts that the string connects to thread in from either side.


Also Something I wanted to ask… how did you go about training for Onshape?.. Our team is just starting to try to CAD the entire robot for the Off season in Onshape but we have always struggled to teach CAD (not just in Onshape but in Solidworks too).

Thank you for the response. I’m still slightly confused on how these parts are used. Do you cap the flower-part on both ends of the tube? I feel like that doesn’t make sense given the length of the part. I fear I may be missing something.

What type of string?

To start new members out, we use OnShape’s “learning pathways” as they’re called. After they’ve got the basics of how the software works we move on to designing FRC related parts such as tubes and shafts and learning how to make part drawings. Traditionally, their first big project is designing a west coast drivetrain, and later they are introduced to the basics of pneumatics and how motors and gearboxes work. Over their first season, new members play supporting roles like designing smaller 3D printed parts and making part drawings and toolpaths. During the following offseason, they will usually take on a the design of a mechanism in order to learn the process in a low pressure environment. From there they can contribute much more during the following build seasons and teach the next kids who join the design team.


Wow Thanks for the quick reply… this really helps

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  1. Is that part under the first stage of the elevator some sort of sensor to zero the position? If so what are you using?
  2. It looks like you have some sort of braking system hooked up to the first stage of the elevator gearbox. I’m curious to know the details of that setup.

There is one of the nuts on either side of the tube, yes. They sit about a half inch in from each end of the tube.


We use spectra cable for the elevator. It’s actually a type of fishing cable, but it has worked great for us!


The elevator brake was something we thought we would need for our triple climb, however we ended up scrapping it because the elevator was able to hold us up just fine with two buddies. So the brake never made it onto our competition robot.


To answer your first question, you are correct. We use a hall effect limit switch mounted at the bottom of the elevator carriage that is triggered by the magnet at the bottom. It can be found here.

If you have any questions specifically about how we use the sensor input in our robot code, I’m happy to answer them. For reference, our 2019 code release is linked here.


Thanks so much for releasing this! I can’t wait to dig through it further!

What were your favorite things about moving to Onshape? What were your least favorite things? Also, just because I love asking this question what is your (or anyone from your team in this thread, for that matter) favorite part of this year’s robot?

Here is a picture of them installed.

We use 94290A550 a lot since we got a lot of 1" thin wall tube donated and love em. They grip really well in aluminum tube and haven’t had one slip or come loose even when cranking down the fastener.


The best thing by far about Onshape is the collaboration it allows. Being able to work on the same sketch or part as someone else and seeing it update in real time is just awesome. We like to refer to Onshape as the “google docs of CAD software.”

I would say my least favorite thing about Onshape is the absence of some basic features that solidworks has such as mirroring in assemblies. Loading speeds were also a problem for us towards the end of the season as more parts got added.

My favorite part of the robot this year is the packaging on the folded up climber. The way it fits under everything with very little clearance is pretty cool in my opinion.

Thanks for the question!