6925 W.A.Robotics - Open Alliance Build Thread 2023

Hello FIRST Community,

Team 6925 is excited to announce that we are joining the #openalliance for the upcoming Charged Up 2023 game! Our team is relatively new to the FRC scene only becoming involved with FIRST for the first time back in 2018. We originally started as a VEX team and competed in VEX until 2017. Our primary (and only sponsor per their rules) is our school, Woodward Academy.

This is our first time doing an open build season, but I think it could be beneficial to us in the form of teaching us about better building practices and better documentation, as well as other teams in the form of sharing our process openly and honestly.

Goals for the Season:

  • Compete as a contender in the PCH district rather than a team that has ups and downs. We want to be and stay consistent.
  • Train new/young members as the majority of our team are seniors or juniors. We don’t want to fall into the trap of losing competitiveness after a few people graduate.
  • Test out the new team structure we have in place. The Mechanical team had a large culture change from just one or two people really doing all of the work (mostly because no one else wanted to) to where this year we have MANY more people that are motivated to work their hardest, and we had to compensate for that by changing the way we do things. (I will outline the new team structure in a later post)
  • Qualify for the PCH District championship for the third time in our teams history.
  • Have an heck of a lot of fun doing so!

Team 6925 will be competing at:
PCH District Gwinnett Event
PCH District Macon Event
(Hopefully) PCH District Championship

Links (will Edit later to post these):


Offseason Project #1:

T-Shirt Cannon:

The post above was a very early brainstorm of what our T-shirt cannon could be. That quickly turned into a whole project, and we went from idea to final in about 2 months. The pictures below are the final product.


Build Process:

  • We decided it would be a good idea to use SDS MK4 swerve modules on it in order to get extra practice with swerve before the season as it is our plan to run the MK4i’s.
  • The frame is entirely made from our spare VEX ecosystem parts (VersaFrame, gussets, etc). For 2023 we want to move away from VEX as a supplier so it was good to use everything up.
  • The pneumatic loops includes a 4500 PSI airsoft tank that feeds a HornBlasters “holding-tank” as we call it, this is regulated at ~120 PSI and has a blow-off valve if it goes any higher than that. This air is then released by any of the three solenoids connected to the tank and barrels via fittings and 3D prints.
  • Everything that could be 3D printed, we 3D printed. It is a very useful resource and it is very easy to get right if you have the right printer. We have 2 MakerBot Method X’s and 2 MakerBot Methods. We use the Method X to print anything that needs to be structural strong because it can print in CFN-12 and CFN. Everything else was done with Black PLA on the regular Method.

Video of us presenting it to our school’s president and vice president


Offseason Project #2:

Improved Pit:

  • Maximize space for pit crew as well as the robot in order to make repairs faster, easier, and reduce mistakes.
  • Create an aesthetically pleasing pit that catches the eye. This is in hopes that it will draw attention from teams and judges so we can show off the improved pit setup and layout

First up, we purchased a 10x10 truss structure branded to our school so it can be used for both Robotics competitions, expos, and demos for any school function or team who requests it. This is something the team expressed interest in last year after attending competition and seeing other teams with this type of structure.

Second Husky:
Secondly we were debating buying the road cases from Omega Case like everyone else seems to be doing. This was mostly inspired by the very detailed 4414 pit write-up. One of our mentors vetoed this because they would have to ship from California and they felt as if it wouldn’t be the wisest. Instead we found this Husky and purchased it from our local Home Depot. This has worked well enough for us as we can store extra parts for the robot in the side cabinet on the left, as well as extra drawers and table space for our many tools, batteries, battery chargers, and a monitor. This allows our old husky (the one on the right of the pit) to be utilized for mostly table space as well as more robot parts and tools.

Really cool project! Just one note - if you’re using SDS tread (or really any kind of tread), be very careful driving the swerve around on gymnasium floors and such, as it could easily leave marks and residue.

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So far we’ve only driven it on FRC carpet and smooth(ish) concrete. It left pretty bad marks on the concrete so we drove it less aggressively and it seemed to calm the marks down a bit.

We are currently using the blue nitrile tread from SDS (which is notorious for the wear and marks), but we think if/when we switch to the newer black neoprene from them it’ll help immensely. (we’re going to use the neoprene for the season and if we have spares they’ll get allocated to the t-shirt cannon).

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From our experience using both, the black neoprene leaves more marks as the blue nitrile tends to degrade itself while the neoprene just degrades the surface it’s driving on. Our carpets got destroyed even more with the neoprene than the nitrile, but our neoprene treads lasted longer.

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(Forgot to link in the first post, linking it here)

Post kickoff update

Hello y’all! We attended kickoff for the PCH district at Georgia Tech this past weekend, and are super excited to play CHARGED UP this year! We met at our lab after kickoff and outlined our needs and wants for the upcoming season:

Needs and Wants


  • Drive
  • PARK
  • Score CUBE on any level
  • Score CONE on any level
  • Intake CONE from human player station slider
  • Intake CUBE from human player station slider
  • DOCK
  • Low CG
  • Fast scoring (fast cycles and good driving)


  • Pickup CUBE from any height
  • Pickup upright CONE from any height
  • Pickup any orientation CONE (from floor???)
  • DOCKING and ENGAGING in auto

Robot Ideas:


  • We have 6 MK4i’s that we plan on using (hopefully only ever needing 4). Big open field = good for swerve. Also an ability to be fast and agile on such a big field can ONLY be a plus.
  • Issues we could face: We don’t have enough falcons to run 4 modules (we have literally 7…), but we do have enough NEOs (though the conversion kits are currently out of stock.) It is not our plan to buy more falcons as is, but we will see.
  • Another problem would be the CHARGE STATION, which we’ve seen be a problem for swerve drives (especially if its AUTO) in some of the RI3D posts. We could theoretically max out our bumper height and see what that gets us. We do have a small idea for a charge station climb “assist” if the robot really needs it but we shall see.


Pink Arm

Currently the Fake Pink Arm (using TTB telescope kit) is the most attractive (but we will see through prototyping)


  • Packaging low = low CG and fast maneuvering
  • Scores both ways
  • Cool design
  • Reaches all heights
  • Meta???


  • Never done by us before
  • Uses CF springs instead of actual driven output, so could be an issue.
  • Not proven nor is it what a TTB telescope is design for.

(crude CAD on the field)

Linear Slider Angled


  • Easiest to build
  • Consistent
  • Uses a COTS system we can buy easily
  • More practice time = faster cycles which could pay dividends to the slower/less versatile scoring style.


  • Generic
  • Doesn’t allow for ground pickup
  • Calls for a larger drivetrain perimeter than we would hope for

Double Jointed Arm


  • Interesting design
  • Allows for quick scoring (if done right)


  • Heavy: the weight also would be quite high on the robot not giving it the low CG we outlined as a point to design to
  • Hard to design, manufacture, and assemble
  • Seems breakable


Claw from sides


  • Easy to build
  • Fast pickup
  • Cones and cubes


  • Not TIOI (touch it own it)
  • Only beginning cones + cones on HP station are oriented correctly
  • Very secure
  • Cones and cubes if measured correctly

Touch It Own It


  • Most secure
  • Ri3D idea
  • TIOI

Stick inside cones (if a cone it tipped over)


  • Allows for sideways cone intake
  • Easy to build


  • Requires separate cube manipulator
  • Would have to push over cones to intake them (probably not the smartest)
  • not secure at all

Cone Flipper (uses to rack and pinion systems to flip cone up)


  • Allows for sideways cone intake


  • Hard to build
  • Requires separate cube manipulator


Its been a successful couple of days, we have some solid ideas already down on paper and in CAD, which we will only be working to improving as well as iterating on in the prototype phase. This hopefully is just the start of some awesome ideas! I will be updating this as frequently as possible, but you know stuff could get hectic. Thanks for reading!

(everyone puts gifs, so i did ahah)


Happy week three everyone! It’s been a hectic few weeks but that’s build season for you…


  • The final design of the robot has been published on Onshape (see CAD link above). The final robot design (for now) is best described as a pink arm swerve bot with a one stage elevator (opposed to the telescoping linear elevator like the traditional pink arms) with a 2018 style touch it own it intake. We like this design because we like the versatility that it offers. Being able to score cubes and cones both backwards and forwards allows for faster/easier full field cycles while under defense (see 971 in 2019 style of driving).
  • We had a tough time fitting everything within the sizing limit while also being able to reach all levels of the node, but we think we’ve found a good fit.


  • The drive base of the robot is complete (we had some issues getting the MK4i NEO pinion kit from AM, there was a QC issue causing us to have been sent the conversion kit with the Falcon gear instead of the NEO gear.
  • Electrical is fitting the final board onto the robot
  • The subframe has been fabricated and is getting painted today and tomorrow
  • The elevator is in the process of getting assembled and should be finished by the end of the week.
  • We really want to get our intake right this year so we are spending a lot of extra time fine tuning the prototype before building the final.


  • We have aggressively set a date for the first iteration of the robot to be complete, we hope to have it done by Feb 7th (Just in time for the 2023 Alfa Romeo F1 car launch haha).
  • Our stop build date is Feb 17th so the first iteration of the bot allows for 10 days of iteration as drive team and programming tune, tweak, and test the robot. (Iteration can also go on after the stop build date, but it will be harder as we are planning on bringing our robot to a practice field near us and going really strong on driving and programming fine tunes until our spring break which begins on March 6th and then ends 1 day before we have to leave for our first event).

Thanks for reading, hope the best for everyone as build season continues!

Small Update:

The bot is coming along nicely, we are right on schedule. The electrical board will probably be finished by the end of our meeting today, and the linear slider and intake assembly will continue as planned.

It will be a big improvement to finish early, with PLENTY of time for iteration, programming, and driver practice.

Another Small Friday Update:

The elevator was complete and attached to the bot, it stays static without power due to the ratio which is what we wanted. There was an issue with spacing the gearbox to drive the elevator that required a shaft change (we just cut the shaft shorter to fit it) only took about 15 mins to fix.

The prototype was finalized and we continued the fabrication of the final intake. I will attach videos of the intake working on cubes and cones at our desired angle.
Cube Video
Cone Video

The board wasn’t quite completed today. Its mainly just cable management and routing left. We had a hiccup with our encoders so we had to re-solder all 4 of them, but at least they’re correct now…


Before Meeting Update:


  • We’ve had some issues with our intake assembly but it should be done by the end of our meeting today.
  • We are in the process of doing A LOT of 3D prints for the robots (including swerve covers and couple of custom brackets)
  • Mechanical is right on track to be done by the 7th (Today lol)


  • Swerve modules have been tested no hiccups, the only thing left to do is set the encoder values and what not and we’ll be swervin’
  • Testing vision with april tags and reflective tape on the new limelight (when it comes in lol)


  • Wire management
  • Test electrical board for the vision testing

Small L this week: We fried 2 Spark MAX’s :sob:, just a mistake on current limits…

Our robot drives!!! video

Robot Handles! Wooo

  • These eyebolts and handles have held 150+ pounds… a team member hung from a tree with the eye bolts + handles screwed into the metal (like on the robot, but not the actual one on the robot haha). So not worried about it breaking.

anyway… here’s another video of the robot driving

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Hey all…

Robot Progress

  • We are waiting for belts and pulleys from WCP for the intake, and then we can finish the robot lol.


  • We have run into an issue where the intake is MUCH heavier than intended
  • We want to pivot to using smaller intake motors from NEOs to NEO 550s (to reduce weight), adding some steel bar as counterbalance on the underside of the elevator in order to pivot a bit better, as well as changing the ratio for the pivot gearboxes.


  • We’ve tested the geometry and measurements IRL to make sure everything scaled correctly from CAD, and it does, so we can score L1,2,3 cubes and cones.
  • We also had a bit of a hiccup with the starting configuration, but it turned out to just be a mistake on the intake assembly, which has since been fixed.



So the carbon fiber 3d print with like 30% infill that was used to mount our intake got rammed into the ground when testing the arm on our robot…
Only one quote to sum it up: Sometimes in life you crank that soulja boy, but other times that soulja boy cranks you…

it was a clean break tho, and no damage on the actual intake so we will just replace it after ironing out some programming troubles…


Do you know how far apart the two wheels in the intake for the cones are?

The shafts for the intakes wheels are 7.5 inches apart, and we’re using the 4" compliant wheels from AndyMark at 35A durometer.

FIRST SCORES!! (and controls update):

  • still some kinks to work out… mainly making the scoring autonomous rather than all manual driver control. should be one button = one score (to an extent)
  • The arms current only programmed set position is for L2 cones and cubes but we are going to set the rest of those tmrw. Idea being we have controls for both directions (forwards and backwards) and for each level (hybrid/ground pickup, L2 cone, L2 cube, L3 cone, L3 cube, substation, and ramp.) It’s a lot of buttons to get to know but I think the way we have it planned will work well. I will update on that soon.

(Obviously we can’t have people put the game pieces into the robot but this was just mainly testing the arm positions.)
First Scores Video

General Arm Movement Video


  • We recently received the rest of the materials needed for our bumpers and assembly of those started today, and should be done by the end of this week if all goes well. (Peep the navy coloring for aesthetics :heart_eyes:)

First time Cycling…

  • Software is still a work in progress, we have a couple of presets dialed in but most of the code is a work in progress.
  • And in the video the human player is just handing the pieces to the bot, in matches we are going to use the ramp to feed cones and cubes as well as ground intake any cubes and upright cones on the ground. Our human player ramp is almost done, we can then use it for better practice…

Cycle Video

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