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Intake Designer

Roller speed, compression and throughput together. The first thing this checks is whether your intake pulls objects in at all, which is not a given.

Inputs

in

Flex wheel or roller, measured uncompressed.

in
in

Roller surface to the opposite surface, whether that is another roller or a fixed plate.

ft/s

How fast you drive at objects. This is what the rollers have to beat.

in

Used for the throughput figure. Roughly how far apart they arrive.

Results

Will it pull objects in?

—

Roller surface speed

—ft/s

Faster than the robot by

—×

Must be above 1.

Roller speed

—RPM

Compression

—%

Squeeze on the object

—in

Objects per second

—

At full speed, if they keep arriving.

Likely failure mode

—

Roller speed, against how fast you drive in—

The roller surface has to outrun the robot or it pushes objects away instead of pulling them in. Half the bar is break-even; a full bar is roughly twice the approach speed, which is comfortable.

Drive onto an object

Drive onto an object
0%

Seen from above, with the robot held still and the field sliding past underneath. The roller sits on one side of the mouth and the plate on the other, your gap apart. The arrow under the roller is which way its surface moves over the ground: pointing back into the robot, it drags the object in; pointing forward, it shoves the object ahead of you however fast it spins. The second half of the slider is the moment of contact, slowed down so you can see it.

How this is calculated

An intake has two jobs that pull against each other. It has to grip the object hard enough to move it, and it has to let the object through without wedging. Almost every intake problem is one of those two winning.

The check most designs skip

roller surface speed = roller RPM × π × roller diameter ÷ 720 (ft/s)

That surface speed has to be faster than the robot is driving forward. If the robot approaches at 3 ft/s and the roller surface moves at 2 ft/s, the roller is moving backwards relative to the object and pushes it away. The intake spins, looks like it is working, and shoves game objects across the field.

This is why intakes usually run on the fast cartridge geared up rather than down, which is the opposite instinct to a drivetrain. A comfortable margin is roughly double the approach speed, so the roller keeps drawing the object in even when the driver is charging a stack.

Compression is the other half

compression = (object diameter − gap) ÷ object diameter

Too little and the roller skids across the surface without carrying it, or lets a second object slip in behind the first. Too much and the object wedges, the motor stalls, and something gives. The failure modes point in opposite directions, which is exactly what theIntake Jam Reliability Analyzerexists to separate once you have a prototype to test.

No published figure says what compression a VEX game object wants, because it depends on the object, the wheel durometer and the surface. The bands this page shows are a starting point from common practice, not a specification, and the right answer comes from testing.

Throughput rarely limits you

objects per second = surface speed ÷ spacing between objects

Almost every intake can swallow objects faster than a driver can present them. If the throughput number looks high, that is normal, and it means the constraint is driving and alignment rather than the intake itself. Chasing more roller speed past that point buys nothing and costs grip.

Sources & assumptions

Cartridge speeds and gear tooth counts are VEX published figures. Surface speed and compression are geometry from your own measurements.

Compression bands are estimated from common practice. VEX publishes nothing about how much squeeze a game object tolerates, and it varies with the object, the wheel and the surface. Use them to start, then measure your own with repeated trials.

Assumes the roller grips without slipping and that the object is round and compliant. A rigid object behaves quite differently: it does not compress, so the gap has to exceed it and grip comes from friction alone.

Every source the site uses, and when it was checked

Save this run, and compare

Keeps what is on screen so you can change something and see both sides of the change. Saved in this browser only, never uploaded.

Make a notebook page

Turns this calculation into a dated engineering notebook page: the setup, data, results, figures, working and sources, numbered and cited. You add the goal, the decision and the reflection in your own words, plus photos and sketches. Print it, paste it into Google Docs, or download a Word file or slides.

My notebook

Notebook page

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    This page

    Our own layouts

    A layout remembers how a page is set up: its type, its system, which parts print and which of your tables it uses. It never remembers a word, a number or a photo.

    Your team kept on this device
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    Your words never written for you

    These are the parts a judge or teacher reads to see your thinking, so the page leaves them to you. Leave a box empty to get lined space for writing by hand. Start lines with "- " for a list. The notes under each box only count and point things out; they never change what you wrote.

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    Rough notes

    The word counts can be measured against a target your team sets on My notebook. The reading level is Flesch-Kincaid grade level = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. Syllables are counted by vowel groups, so the grade is an estimate of the school year the writing reads at. It says nothing about whether the writing is any good.

    One part at a time, with a clock. At the end of practice, while you remember it.
    How you tested your details

    Fill in what applies. These print as a small table under the method.

    Before and after

    Compare this calculation with a run you saved earlier on this tool (under “Saved runs”). The page shows what changed and by how much.

    A line through the data from your recorded table

    Pick two measured columns from the same table. The page plots them and draws the least-squares line, only across the range you measured.

    Robot log a CSV from the robot's SD card

    Load a CSV your robot saved. Pick the time column and up to three columns to plot, and type their units. Only those columns go on the page; the file stays on this device.

    Two versions' trials your data, compared

    Pick a column of recorded trials for each version, from this page or another saved page. The page shows both averages and a 95% range for the difference. The numbers are copied in when you pick them, so later changes to the other page don't change this one.

    Options compared your scores

    Score each option 1 to 5 on each criterion, and weight each criterion 1 to 5 by how much it matters. The page only multiplies and adds.

    Photos and sketches stay on this device

    Up to 4. Paste a screenshot with Ctrl+V, drop pictures here, or pick them. Photos are shrunk before they’re kept, and an unsaved page keeps them in its draft. Use Mark up to draw arrows, labels, dimensions and numbered callouts on a photo. Mark one photo Before and one After to print them side by side.

      Test plan written before testing

      Write this before you test: the question, what you expect with a number, and what result would make you drop the idea.

        Build steps our build

        One row per step, in order, so someone could rebuild from this page.

          Parts used our parts list

          Lengths in holes are also shown in inches between the end holes. Weights are only added up where you type them.

            Plan the cuts: packs every piece of one part (sizes in holes, or inches on the hole grid) onto whole sticks of the stock length you type.

            Ways it could fail our scores

            List the ways this could fail. Score how likely (1 to 5) and how bad (1 to 5); the page multiplies them and puts the biggest risks first.

              Designed against built our measurements

              What the CAD or the plan said, and what you measured on the robot. The tolerance is yours.

                Changes from the last version our changes

                What changed since the last version, why, and which result it was meant to move.

                  That page’s settings, results and first photo are copied in and set beside this page’s. The result each change should move is looked up on both pages.

                  Tasks our plan

                  What needs doing, who, and by when. Open tasks carry to the next meeting page until someone ticks them done.

                    The pages behind this idea our evidence

                    The pages in this notebook that show the idea being tried, measured or changed. A judge reading the claim can turn straight to them.

                      Time spent our hours

                      Who worked on this and for how long.

                        Session log what we did, as we did it

                        Notes taken during a session. The time comes from the clock when the note was taken; every word is yours.

                          Size limit does it fit?

                          Type the starting size limit from the current game manual, and the robot's size as designed or measured, in inches. The site doesn't store the limit, because it changes with the game.

                          What broke from your breakage log

                          The breakage log is on My notebook. Copy it onto this page as a table, as it stands now; later entries don't change this page.

                          CAD model which version this page is about

                          Paste a link to the model (Onshape, Fusion or anything else) and the name you use for this version. For Onshape, the page reads from the link whether it points at a saved version or a workspace that keeps changing. Nothing is fetched.

                          Your code
                          Comments notes for the team, not the page

                          A teammate or coach can leave a note here. Comments stay beside the page, travel with it in exports and links, and don't print unless you tick them under Include.

                            Sources you used besides this tool

                            Videos, other teams, manuals, people. The tool’s own sources are cited for you.

                              Sign-off
                              Include

                              Press a ? to see what an option is for, or read them all on How the notebook tools work.

                              What “The calculator’s figures” is for

                              The calculator’s own diagrams and charts, numbered as figures and drawn from your numbers. Judges look for pictures that explain a design.

                              What “How it was calculated” is for

                              The formulas and steps the calculator used, so a reader can check the arithmetic for themselves.

                              What “The calculator’s warnings” is for

                              Things the calculator flagged, such as a motor near stall. They’re quoted and credited to the calculator, so they never read as your conclusion.

                              What “The calculator’s notes” is for

                              The calculator’s plain-language notes on the result. Off at first, because they read like conclusions, and the conclusions on a page should be yours.

                              What “Lined space” is for

                              Ruled lines under any part you haven’t written yet, so a printed page can be finished by hand.

                              What “Writing space as” is for

                              The blank space for handwriting as ruled lines, a dot grid or quarter-inch squares. Dots and squares suit sketches and hand-drawn graphs.

                              What “A summary under recorded data” is for

                              The number of readings, the average, the spread, the lowest and the highest under each table you recorded, worked out from your numbers. It shows every run counted, not just the best one.

                              What “Words used” is for

                              A small box with the site’s one-line definitions of glossary terms the calculator used, for readers who don’t know them. It never looks at your own writing.

                              What “Robot at the time” is for

                              The Robot Profile as it was when the page was first saved, so weeks later you can tell which version of the robot a test was run on.

                              What “Long tables in full” is for

                              Long calculated tables printed complete on an extra page, instead of every few rows on the page itself.

                              What “Fit on one sheet” is for

                              Smaller type and shorter tables, aiming for one printed sheet. Use it when every entry in your notebook should be a single page.

                              What “Wider left margin” is for

                              A wider left edge, so the page can be hole-punched or bound without losing any words.

                              What “Larger type, for reading aloud” is for

                              Bigger print with more room between lines, for the team member who reads the page to a judge. It overrides Fit on one sheet.

                              What “Our rubric scores” is for

                              Your own scores against the rubric, on a sheet of their own, for checking a page before a judge does.

                              What “When this page was first saved” is for

                              The day the page was first saved, printed beside its date. It shows the notebook was kept while the work happened.

                              What “Teammates’ comments” is for

                              Prints the comments teammates left on this page at the end, marked as not part of the page. Off at first, because comments are notes for the team, not for judges.

                              What “Show every table and block” is for

                              Shows every table and block in the editor, not only the ones this type of page usually uses. It changes the editor, not the printed page.

                              Rubric check

                                This checks what is on the page, not how good it is. Clear, specific writing in your own words is what earns the top marks.

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                                Where this goes next

                                Explore further on the full map

                                Where the answers on this page can be used, and which tools could have given you the numbers it asks for.

                                Comes after

                                Intake Jam Reliability Analyzer

                                You are here

                                Intake Designer

                                Where your answer goes

                                Motor Power Budget Checkercheck your intake motors still fit inside the robot's motor power limituses your motor count againShaft & Structure Load Checkcheck the roller shaft survives the torque when an object jams itbrings your gear sizes with itIntake Jam Reliability Analyzerlog real pickup attempts to see if the design works as often as predicted

                                a number carries across the next question it raises

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