pic: Spectrum 3847 - 2017 CAD Model: Gamma Ray

[SIZE=“3”][COLOR=“Indigo”]Spectrum 3847 Blog[/COLOR]
[COLOR=“Indigo”]The Blue Alliance Blog Post[/COLOR][/SIZE]
Blog posts with links to download the full CAD model either as Solidworks files from our GrabCAD partner space or a STEP file.

[SIZE=“3”][COLOR=“Indigo”]Spectrum 3847 on Episode 4 of check_in[/COLOR][/SIZE]
With a discussion about some of the design decisions that went in to this robot.

That arm on the front stays inside the maximum robot volume, right? It looks like you’re going with the tall dimension set, and it also looks like lowering that arm is against the rules.

That looks like the short dimension set to me.


Teams need to make sure they read all rules pertaining to robot size carefully. I would hate to see a robot this well designed get to a competition and then not pass inspection.

I’m sure they know what they’re doing and have read the rules - they’re a long standing veteran team who’s built high-quality robots for years, who publicly posted a full cad of their robot in week 4.

You don’t think it’s more likely that you have an inaccurate perception of the robot’s dimensions?

It’s not against the rules to lower the arm as long as the robot still fits within the volume with the arm lowered (i.e. their chassis is shorter to compensate). This is clearly the case here. If the arm doesn’t go past the bumpers then it’s legal for it to be lowered even at max dimensions.

It’s Spectrum, I’m sure they’re in the volume. These guys do their due diligence. You can lower an arm outside of your bumpers as long as it all stays within the appropriate robot volume.

Looking slick Allen!

notmattlythgoe is correct, we are using the short configuration. We are 29x29 so we have room for a 4" extension off either side. The gear collector also fits within our bumper cutout.

See these photosfor reference. The pic with the grey gear is current, the pic with the yellow gear is from an older revision, but demonstrates how the intake fits inside our front cutout.

The robot frame is a ~29in square making our dimensions with bumpers about 36" square. That gives us 4 inchs of room to extend past the bumpers. The mecanum intake and the gear intake both come close to the full extension limit but can’t possibly break it.

And of course we are short. Top of the robot is 23.8in I believe but the student that’s doing most of the shooter CAD can tell you for sure that we are under.

By my best memory we are ~23.97. I will update this post later in the evening if I’m way off.


Really cool bot, love what your team is doing with the open build/blog. Seems like a great learning experience for your team.

Whats the process for scoring the gear once in the gear holder?

Great work as always,


Very nice. What is the upper appendage intended for?

They talk about some really good details of the gear intake here in the video.

This makes me wonder how they’ll inspect boundaries this year. Our arm is 1" within the boundary with fully-down, but comes to within 0.25" of the boundary during articulation up/down.

In previous years where they had appendage requirements they made the teams extend out to their furthest point and then measured them.

The roller with the mecanum wheel is our full-width fuel intake.

Vectored intake wheels are the best.

Great looking robot there! Awesome cad work as always.

In our testing it hasn’t been difficult to deliver the gear out of the intake by just reversing the roller, lowering the arm, and driving backwards once the spring has pierced the gear. We were hoping for a cleaner release but couldn’t get the gemotry of our first system to a point we thought it would be robust enough for the whole season. We haven’t tested this geometry on a rolling chassis yet and that will be one of the first things we do when parts come in next week.

I’d assume we will be iterating on the drop off portion all season to make it as fast as possible without compromising it’s pickup speed and ability to securely hold the gear during high speed collisions.

So if “vectored intake wheels” are now a thing, does that mean we can add mecanum to the list of misspellings of mecanum-err-vectored intake wheels?