FRC 4481 Team Rembrandts 2023 Build Thread

Up till now it’s mainly done by manual control and eye sight. (Hence it goes wrong a couple times)

We’re thinking and testing different ways of using sensors this week to see if we can speed up the process and make it less relying on the driveteam.

If the cone is upright in the spindexer then we should grab it and score it from the front/intake side of the robot. We can reach mid and low from that side.


This looks incredible! I was wondering what the angle is between the sets of compliant wheels and the center of the spindexer. We’ve been prototyping a spindexer but definitely have the wrong angle and are trying to fix it. Did you just choose an angle or did you test until you found the right one?

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I just watched your video of practice and can’t wait to see this thing in competition!

Do you have plans for bringing in the cube in a more controlled fashion? I imagine flinging it up in the air like in the video is not ideal when you are on the field with other robots pushing and shoving.


Currently the intake is geared 1/3 which is to fast in general so we will decrease the speed and increase the torque. We will try with 1/4 - 1/4.5 an 1/5 ratios and see what works. Additionally we will likely have 2 sperate intake speeds, one for cones and one for cubes. This will likely make the cubes come in in a more controlled fashion.


Do you mean this angle?

We tried to fit everything in this design and keep enough room so a cone could easily pass through to the spindexer itself.

*note: dimensions are in mm


Pit Flightcase

We are proud to present our new 2023 pit flightcase and robot cart. We have create a new post about it, so you can find all details and an explanation video there!

FRC 4481 Team Rembrandts – Pit Flightcase

This post was written by: @Niels_Heijden


The flight case and the robot cart are beautiful and the functionality and compactness make real companies envious.


Yes! Thank you so much.

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We are following a similar approach with our robot. Slowing down the cube was a must. In our case we also just run the top roller which helps by giving the cube more top spin.

Have you tried grabbing the tube with your gripper motors instead of trying to shoot the cube into the spindexer? Basically have the gripper just on the other side of the floor pick up rollers.


We did try that and that is a great alternative:

Only we feel like using the intake might be faster if we can get it to intake the cubes in a controlled manner. It would save us alignment time.
And as we turn the intake from a single neo, we can not turn the top roller individually currently otherwise that would have been a solid solution.


So I was looking through your YouTube videos and saw that you guys have been starting to test the spindexer with sensors. What are you guys measuring to have it stop? Is it the distance away from the base of the cone?

Videos we got so far is based on driveteam judgement and eye sight. Plus a button that does like “rotate spindexer for 45 degrees at X speed”

We’re currently try to get the logic to work with 2 photoelectric sensors and an end stop. The spindexer is powered by a Neo with a trough bore encoder.

We hope we can have it all figured out and working in our rev2 robot that is being built this weekend IF we receive all our sheetmetal and tubes in time… :crossed_fingers: We might have some results to show on our current prototype robot if it all works in some time…

Current idea for the spindexer is to:

  • Intake cone and transfer into spindexer
  • Once in the spindexer a sensor detects the game piece
  • While spinning it will hit a end stop and by rotating clock wise & counter clock wise plus another sensor we hope to be able to control the orientation of the cone good enough.

We did some different angle testing and noticed the cone didn’t need to be on the millimeter accurate positioned. Check that video out here:

Edit: Person in the video shouts “Kox” which is a name from one of our team members :wink:


What type of piston do you use for Quickclaw MacGraw?

It’s a 20mm bore SMC cilinder with a stroke of 80mm.

@Woetie that’s correct right?

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That is correct. Do note that we use a print which slides of the cilinder rod to reduce the stroke. From the top of my head, this print is 37mm. You can play with this to increase/decrease the compression on cubes.
Link to the cilinder:

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What are you using for your telescope?

Not sure if this has already been tried and/or what you are referring to as an “end stop”, but has the team considered a passive filter for indexing the cone in the spindexer? Maybe a small protrusion that allows everything but the flange to get past it. Obviously you’d be limited to only spinning the spindexer in one direction but I assume that wouldn’t be a problem. Potentially also retractable with a small pneumatic cylinder or a servo so that it doesn’t get in the way for cubes/when the cone is first acquired. Similar to teams that had deployable kicker wheels on spindexers in 2020 to pull the power cells into their shooters.


On your intake is that smaller roller that is used to knock the cones down as they go into the robot, powered or is it just free spinning?

It’s a rigid crossbar that’s bolted in the intake side plates from both sides. Just an aluminum round shaft with tapped thread in both sides


Could you specify your questions a little more? What are you referring to?

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