Team 3357 The COMETS is proud to present our robot for the 2024 season: Vaisala
Students and mentors will be on this post occasionally to answer any questions you may have – please don’t hesitate to ask! The COMETS wish everyone good luck for the 2024 season!
~Presto (つ≧▽≦)つ
Here’s our reveal video for this year!
COMETS 3357 FRC Reveal Video 2024: Vaisala
Some fun robot stats for 2024:
24"x28" frame perimeter
75 lbs (no ballast this year, whew!)
And some action shots:
What are those intake rollers made of?
What is that drivetrain!?!!
Jkjk
Looks nice. I see you have the sector gear captured , hopefully avoiding any skipping.
Beautiful bumpers as always.
Some hopefully helpful advice:
The rsl and camera uprights could probably do with a string stretching between the tips to avoid notes getting caught.
How consistent is the amp scoring design?
it’s a silicon “floated” over our tubes, i believe spectrum 3847 has a tutorial?
What are those intake rollers made of?
As Addison mentioned, they’re polycarbonate or aluminum tubing (of varying diameters depending on intake vs indexer) with white silicone tubing overtop.
We use the Spectrum method ™ to seat the undersized silicone onto the roller tube.
What is that drivetrain!?!!
Thanks Skye! This will actually be our 2nd competition swerve robot! 2011 was our first, back when I was a young lad 
It’s fun to be back on the swerve train, but definitely sad to see WCD in such a lull like this. I’m certain in the future it’ll be back with a vengeance when we get an obstacle game!
…probably do with a string stretching…
We already have plans for this, it just looks super goofy so we left it off for the reveal! Other areas of the bot are likely to receive this treatment as well. It is always a good idea to think through how and where gamepieces can get stuck when we have such a strict single piece limit like this year.
How consistent is the amp scoring design?
We have a few different methods with various states of effectiveness, but the one you saw here was the most flashy. This will change as the season progresses and as the other techniques get fine tuned!
that shooter deck is PACKED. wow
Are y’all not worried you may be pushed around by other robots? Seems like there will be decent congestion on the field this year.
Incredible robot btw, looks super clean and I’m excited to see y’all compete.
Our robot is also pretty light, 88 lbs no battery or bumper, and we’re hoping that the extra speed will mean that we can just avoid other robots. We don’t have to worry about being pushed if they can’t catch us.
This year for our sector gears we wanted to try a new gear profile. The last time we had a large custom gear was our turret in 2022, that gear was made in 3 operations on our CNC router using different sizes of bits because we needed to use a 1/16" bit to get into the root of the teeth. To make manufacturing easier this year we used a roller pinion gear profile, this lets us use a 3/16" router bit for all the machining.
So far with a few hours of drive time, we have had no noticeable wear and very low backlash, so we’re very happy with this gear.
The gear profile is an equation driven curve and the equations came from team 3476’s work on their 2019 turret.
This is the exact philosophy we were pursuing this year, you hit the nail on the head. Small (within the practical limits of the drivetrain) and light to stay fast and avoid defense.
Are you at all worried about consistency of amp scoring? It seems like it would have to be really precise to work every time
Did you use simple green like suggested in the video? We found there to be a reaction between polycarb and simple green where it would make it crack to our unpleasant surprise.
We used about 3 drops of hand soap in a cup of water. Polycarbonate is sensitive to a lot of chemicals apparently.
Yeah that was more of a trick shot. We have other plans for actual play.
I wanted to use dish soap but all we had in the shop was simple green and a heavy duty degreaser and thought the simple green was the safer choice 
Tread Cutting Die
This year we decided we needed a faster and more consistent method to cut treads for our wheels. Here is what we came up with.
This is a die that cuts a tread complete with holes in a single operation, it requires an arbor press, soft plastic cutting board and a stiff plate larger than the tread. This design is for Rev’s MaxSwerve aluminum wheels, but a similar die could be made for any wheel. The die its self is a milled block of aluminum with threaded holes to mount hole punches and blades. The hole punches are 5mm punches from Sailrite with a M8x1.0 thread, the blades are generic .937” steel rule die blades off eBay. The blades cut and drilled fairly easily but I used oversized holes so they weren’t doing the locating. The hole punches don’t have a lot of thread so I taped from the far side to get the cleanest threads right up to mounting face. The hole punches are a bit fragile so don’t grab them by the sharp end with pliers.
This design requires very short screws and installing the hole punches is somewhat difficult, so the design could be refined to hold the blades in another way, but this works for now.
Using the die is very easy, and complete treads can be made in less than a minute. Press the die into the back of your tread material starting on one end and moving to the other. Starting in the middle requires much more force. Once you have pressed the die into the tread flip it over to check that you cut all the way through and can see the blades. You’ll need to push the complete tread out of the die with a hex wrench or similar through the pushing holes, and you are ready to cut the next tread.
How many sparkmaxes did you guys use? Any ideas on how to not rely on a canivore which is not compatible with Rev sparkmaxes?
Spark maxes have a lot less can utilization than CTRE motors so you don’t need a carnivore.
We have 8 on swerve, 4 on our intake/index/shooter system, 1 motor for climb & 1 for pivot. Each of those require a spark max for 14 total.
I just checked with our lead programmer regarding CAN bus utilization, and we typically sit in the 50 to 60% range. Even with swerve, 14 motors isn’t all that much so I’m not surprised at that. I’m not an expert when it comes to reducing utilization, however there have been some lengthy discussions about it elsewhere on CD if you search around!
As a general rule of thumb, to reduce controls complexity (and utilization) you need to reduce robot complexity as well. Of course this is much easier said than done, and requires a great amount of discipline in the early build season weeks. Also I know there are polling rate tweaks you can make in the Rev hardware client, so explore those options if you haven’t yet!
