The Great Ball Contraption

"It can be really simple, or devilishly complex as time allows!"





Chain lift: continuous chain with “buckets” that lift balls one (or more) at a time. Can act as a clocker, delivering balls in a continuous measured rate. Can deliver vertically.

Conveyor: moves balls up incline (or horizontally). May use idler wheels/gears to change shape of path. To insure feeding from hopper, “bumpers” or “sweeps” might be used to stir the hopper.

chain-based: continuous chain drive, with “paddles” or blades that sweep balls from input hopper to top. Can grab more than one ball (depends on width of conveyor). Small footprint, input hopper geometry critical.

belt-based: series of overlapping tank tread belts lift balls up shallow inclined path, with perhaps axles or other small thin parts keeping dumped balls from being pinched or spun between consecutive belts. Probably limited to very shallow slopes.

custom belt [SMART]: wide belt of frictionless-pin-linked studless beams carried and driven by various tires instead of gears. Heavy, wide, but novel.

multi-bladed/propeller [SMART]: series of rotating blades projecting thru the conveyor floor, such that the first rank of blades lift the balls up & forward, and as they rotate back down the second rank of rotating blades continues the process.

roofed: smooth sloping floor of conveyor just holds balls against moving roof that pulls balls up the passive floor. Feeding may be a problem (perhaps from side, not end of belt). Maximum angle uncertain.

tank-tread roof: Balls “roll” up floor ramp at half the speed of the belt, rolled by the moving roof above. May be limited to single tank tread length (belt-to-belt feeding unsolved).

custom or link-based roof: moving roof uses hanging “scrapers” to snag balls in a pocket or cell, dragging them up the ramp.

Marble pump: reciprocating piston lowers a ball from the hopper and pushes it into the output stack above. Limited by the weight of the stack above (“tube” above must resist bursting due to column weight, piston must have enough force to lift entire column). Ideal for clear side to show pump mechanism, but may weaken. Requires priming, and draining ability (when hopper runs out, column above pump is inaccessible). Can function as a clocker

Ferris wheels [SMART]: rotating series of cages, sweeping in a ball at the bottom (unsolved) and dumping them out at a high platform that tips cages. Can function as a clocker, requires a wide footprint.

ferris lock: the idea is to use a long tray or “stretched cage” attatched to a wheel or large gear. It can scoop at the bottom of the cycle, and dump into a linear tray or chute at the top (lifts half a cycle, or one diameter, assuming non-pivoting tray with three sides (only the roof open)), or it can rise from under a bin and tip out near the top (lift only 1/4 of circle, assuming non-pivoting tray)

clock lift [Steve]: picture a slightly tipped-back clock face, with a “C” shaped cup on the end of the minute hand. At the bottom (“6 O’Clock”) it scoops a ball (or balls) into the cup from a bin, rotating them up the face of the clock. Near the top (say between 11 & 12 O’Clock) the face is cut away, allowing the balls to fall out and into a chute or receiver.

wheel lift: based on the Hailfire Droid wheels, wheel lays in a slightly inclined cavity with the bottom a shallow trench to lower the inner rim level with the attatched hopper floor. At the top of the cavity the rear wall is missing, allowing balls to roll out of the open cells attatched rigidly to the wheel’s inner rim. Wheel can be rotated by resting it on regular driven wheels on the inner border of the cavity. A second wheel can be used as a 2nd stage, set above and just behind the lower wheel/cavity assembly.

Shooter: two high-speed counterrotating soft wheels grab ball and launch it upward. May require a cloker to make sure mechanism isn’t swamped by too many too fast, and feeding into the wheels could be tough. Height of throw may vary, but angle need not be dead vertical, and a high catchbasin could collect balls at the top. Difficult to ensure no dropped or lost balls, consistancy could be difficult as well.

door-spanner: toss balls one by one over the entry door to the room, catching in a larghe catchbasin (perhaps a fabric sheet funneled down toward the lower end).

juggler: more than one throwing device going to one or more catchbasins, with the possibility of interleaved streams.

spanner: balls thrown over a perpendicular module stream

Gantry crane [SMART]: grabbing claw on a static gantry can travel and descend to pick up entire crates of balls at once, moving them to a high ledge (or between one or more ground stations). Might, if high enough, allow a stream of modules to run under it.

cable-car: grasping crate claw drops from a wire-riding cable-car. Could cover large distances quickly, although maximum lift weight is likely low, and tension in the cable (metal wire) needs to be high (firm anchors, non-LEGO, likely needed).

Arm: “standard” arm that can grab a crate, lifting it and placing it somewhere else. Lots of variations

crate [SMART]: two gripping fingers (horizontal to grasp sides of crate, or vertical to grasp top & bottom edge of crate) close on crate and lift it off the surface before either roating it to a new location (onto an elevator, for instance), or rotating at the wrist to dump it into a hopper.

single ball: Two fingers can pick out a single ball

multible linkage: using a parrallelogram linkage, an arm could grab a crate and lift it to a much higher level while keeping it level, depositing (or dumping) it in a high hopper.

Archimedes screw: Possible shallow lift mechanism (are worm gears too small?)

Wind lift: use a fan/centrifugal fan/compressor to generate a strong airflow that can either entrain balls up a sloping ramp or even up a vertical shaft. Two issues: (1) making a powerful enough LEGO fan (or using a non-LEGO fan) to get the airstream, and (2) making sure that the “lift column” never becomes so saturated with balls that it collapses (either time the balls, or better yet only lift a new ball when an old ball has fallen out.

Scissor lift: flat platform on a scissor lift, dumping platform (with hopper/crate) at top as outer edge of platform catches under a lip. Ideal for pnematics.

Step feeder: series of vertically oscilating ledges or steps, each just a little bit higher than its neighbor and only as wide as a ball (or slightly less, actually). The first step lifts a part (ball) out of the bin, and at the top of the lift the ball rolls onto a static step with another moving feeder step on the other side, which repeats the process. Steps can be driven by cams on a central drive shaft at the base (or partway up).

single-acting: odd-numbered steps oscilate up & down syncronously, while even-numbered steps are stationary (passive “holding pens”). Since all the moving steps are syncronous, they can all be part of one structure, moved by a cam at the base (this is how toys, such as the “Playful Penguins”, often work)

double-acting: every step moves up & down, with alternate steps 180° out of phase, potentially much faster.

Elevator: single “mounted” crate that can be raised and lowered along a single path. A feeder ramp can dump balls into it: when the elevator is lifted, it can flip back the edge of the ramp, temporarily impounding any oncoming balls. The descending elevator restores the ramp and the flow of balls. At the top, the crate could be emptied in several ways:

trap doors: or suddenly exposed sides. Make one side of the crate a hole, blocked only by the wall of the elevator shaft; at a certain level (perhaps selectable) the shaft has a gap in the wall, spilling the balls.

dumpable: at the top of it’s travel, the crate is mechanically dumped, possibly be “tripping” on an edge at the top, for instance.

There are also at least two ways to drive it:

cable-based: a string (or perhaps chain links) pull the elevator up and down the shaft

cog-based: either an externally-driven gear cranks up & down a rack on the side of the elevator car (suitable for short drops only, unless you want a long rack sticking out), or the elevator car itself has a motor-powered gear that engages a static rack fixed to the elevator shaft.

Check valves: use some sort of check valves along a linear track to allow episodic pumping (perhaps be tipping the trough, or moving the roof or floor up & down or forward & back repeatedly). Requires only limited travel of the pumping mechanism, depending instead on the check valves (beams that fold one way but not the other?) to retain the balls in each compartment after a single pump cycle. Swinging gates made of axles, that fold one way but are blocked the other, would be ideal, as they could interpenetrate yet not let balls through.


Water-wheel driven: a faling or descending stream of balls turns a paddlewheel, which in turn runs a small lift (like a chain lift or Ferris wheel lift) to pull a few balls out of the stream and raies them again for more processing.

Ramps: mobile carriers like dumptrucks or forklifts might ascend ramps before dumping or tipping their crates, allowing unloading at a higher level. Does require rather wide ramps if vehicle turns at top. Backing down after delivery might be easier, using guiderails on ramp instead of line-following, but will still require a significant ramp.


Ramps/chutes: Made from two upsidedown 1xn technic beams seperated by a short studless beam(this can be used to join two sections of chute as well). When guides are needed (such as when dropping a beam height, or dropping and turning 90°) beams can be pegged on the outside to “raise a rail” (with 1/2 pins in place the area between two rails can be narrowed by a tile on each side, perfect spacing to guide the balls into the center of the downstream chute). Lightweight & part-efficient.

Funnel: made from four “bowl corners” like in set #3433 NBA Arena, balls can be injected tangently, allowing them to orbit the funnel until dropping into the center drain hole.

Ski-jump: balls are jumped into the air off a gravity-fed ramp

Loop: balls run down a track to gain enough speed to go through a loop or two, like a rollercoaster.

Trampoline: airborn balls bounce off a hard flat surface to the next element. Ball stream will have to be clocked (or at least spaced), and surface to bounce off of must be very ridgid (little or no energy loss).

Sorters [SMART]: device that takes a mixed stream of balls and seperates them into soccer & basketball streams. To a light sensor, a spinning basketball is fairly uniform, while a rotating soccer ball should oscillate bright-dark. If the entire contraption uese only soccer balls, a sorter at the end could seperate out basketballs to keep them contained in a single module.

mixers: mixes together two or more incoming streams of balls. This could be passive (just add the two streams together; combiner) or active (drop both streams into a single hopper that is well-mixed, from which a homogenized stream can be sourced).

Overflow routes & bank storage: in case the ball stream can’t be processed fast enough (like by a sorter), an overflow route could be provided that by-passes or stores the excess until it can be precessed.

Pegboards: balls can be dropped into an isometric (triangle-based) array of pins, forming a binomial distribution at the bottom. Loud, fun, and allows a certain percentage to be siphoned off from one of the outer bins if desired.

custom boards: instead of a simple array of pins, balls roll down an inclined baseplate (32x64, for instance) that can be replaced with other, custom-made baseplates. This would allow spectators to design a portion of the mechanism, with the balls collected in a trough at the bottom.

Flip-flops: A device that shunts successive balls down alternate streams. A simple example is a “Y” shaped pivot, where the stem of the “Y” points up. When a ball is deflected off one of the arms on its way down, it tips the stem to the other side so the following ball is deflected off the other arm, reseting it.

digital logic: it might be possible to make digital devices, such as OR, XOR, AND, etc. Synchronization might require a “master clock”, with one or more balls cascading down an independatn series of chutes to “trigger” the gates.

Train [SMART]: loading & unloading traincars with crates of balls(via arms, cranes, etc.)

Land monorail: lacking trains, how about a wheeled car or truck, that travels over a “rail” of 2xn bricks to guide it, just running back & forth over a straight line. Stopper blocks at the end could signal loading and unloading, or stations mid-line could be signaled by the color of the central rail. Could function as a train (carrying crates) or have specially designed hopper that can dump on command (like a coal car or a log carrier).

Flatbed truck / landtrain: use a flatbed truck (or series of them) to move crates around. Truck could be loaded & unloaded via arms, forklifts, etc., or even gravity-feed loading might be a possibility.

Dumptruck [SMART]: A robotic line-following truck that could pull under a hopper (like a coal car loader) to recieve a load of balls, then proceed somewhere else to dump them (or elevate the entire bed and then dump, higher).

Forklift: line-following forklift that can lift and move crates, controled by barcodes along route (for ease of re-structuring the route, as well as possibility of dynamic control by changing barcodes “on the fly” - a hopper along the route could signal it needs service by deploying or changing a barcode along the route). Loaded crates could be “pushed” out of position by forklift delivering a new empty crate (with the newly released “full”crate then being picked up), or “full” crates could be pulled out allowing a new empty crate to slide down a ramp into position.

tilters [SMART]: slides forks under a crate, tilting forks up slightly to lift

lifters: forks can be raised vertically to lift crate a little or a lot. Crate could be placed on a high platform that could firmly catch then rotate to dump the crate (dumping could be “pushed” by raising the forks to push on a mechanism, with platform/crate returned to neutral via gravity).

dumpers [SMART]: forks lift, then at the maximum height rotate or tilt to dump crate

warehouse: a defined area for racks to hold multiple crates, with the forklift either “looking” for crates it needs (perhaps empties to the left, full crates to the right) or remembering where crates of interest are located.

Clockers/Smoothers: mechanically time the release of balls in the stream, limiting it to one per second or some similar, fixed rate. These can “smooth” an input stream, taking an episodic (crate-dumping) stream and making it uniform.

chain lift: a simple timed lift, one ball at a time

revolving door: as a rotating device turns, it can only grab one ball at a time (in a gap in the wheel) to release. Probably works better with the rotation axle oriented horizontally (either the gap acts to grab and lift over the wheel one ball, or with a series of two offset wheels a “chopper” mechanism breaks the stream into one ball units), not vertically as with a true “revolving door”.

choppers [SMART]: arms oscilating much like a mechnical leg can segment the ball stream into one-ball units.

balance-based: used in some wooden marble machines, the first marble triggers the release of the next after a certain time (as it goes down-run). A weak example would be a slightly tilting chute (or linked chutes), such that when the lead ball rolls off the far end the chute tips back, re-aligning with the feeding chute to allow another ball into the mechanism. As the new ball enters the mechanism, it tips the lead end of the chute up slightly, blocking any marbles behind from entering the mechanism.

Counters: keeps a running tally of some type of the balls running through the mechanism

mechanical: clockers have the nice property of delivering one ball at a time, allowing ball-counting either via timing (mechnism moves this long must deliver this many balls) or a purely mechnical means like that used in the rolling ball clock (filling & thereby overbalencing a tray, dumping the balls and passing a single ball onto the next ramp or tray. this can be cascaded down any number of levels).

digital: balls might be counted digitally via interrupting a light sensor (although consecutive balls might be a problem if a clocking mechanism isn’t used). Sorters can essentially do this as a by-product, as they need a digital knowledge of the number of balls anyway.

Log flume: long runs of a single ball stream. Ideally these should be along two rails or with only two points of contact. This requires either thin rails (plates with handles work well), or a 90° flume tilted so that it is “point down” (difficult geometry)

Air-suspended: a ball could hover in a rapidly ascending stream of air, possibly even allowing a series of balls to occupy the spot (incoming ball knocks the hovering ball to the output chute). Requires a good fan or other airstream.

Ben’s racetrack: Use the car tracks as guides for large number of balls, for rolling down slopes or perhaps even jumps. A small motorized vehicle could even run around a loop of track,plowing the balls ahead of it to a gap in the track where the balls fall off.

Roadplates: these can serve as large flat areas to collect marbles, or serve as bins (see gabage collecting below) or wide marble runs.

Garbage collecting: balls are dumped wholesale into an enclosed arena or field, where a mobil ball-harvesting robot scoops them up, delivering then periodicly to a waiting hopper (or crate).

Turntable scrambler: balls are dropped near the center of a rotating turntable, to be flung off by the rotation. Potentially turntable could be large (baseplate) and have a series of obstacles on it

Crate options , output (things to consider in a Type 2 standard): In order that no balls are spilled, there needs to be consideration given to how to “swap crates” at an output. Some options:

Crate pushing [SMART]: An empty crate is pushed into an active output zone, displacing the previously filled crate, which can then be safely picked up.

Gravity-driven crate feeding: Active output zone is at the end of a sloping ramp filled with empty crates. When the crate in the output zone is removed, a new crate from the feeder ramp will slide into position.

Triggered hopper: High hopper is filled by the output stream, with a trap door in the bottom (or side) that is only opened if a crate is present in the output zone. With a normally empty output zone, balls accumulate in the hopper until a crate is placed in the cradle, which opens the trap door filling the crate all at once. When the crate is lifted again, the trap door closes & resumes accumulating balls.

Impounding ramps: Output zone with a crate is fed via a ramp with a flip-up edge. When a crate is lifted the edge is tipped back, temporarily impounding the incoming ball. After a new crate is placed in the output zone, the edge of the ramp flips back down, releasing the impounded balls and resumes filling the new crate.

Stackable crates: A fresh empty crate is placed above the current active crate in the output zone. Some mechanism (yet to be determine :-) ) then removes the lower crate and lowers the upper crate into the output cradle.

Crate options, input : Forklift raises crate into a high rotating cradle. The forlift then pushes up on the back of the cradle, rotating it forward and dumping the balls from the crate. The crate can then be removed to be reused.

Hopper busters : Even if the lift mechanism works reliably, the hopper feeding it has a tendency to jam. Smooth & non-narrowing would be best, other options:

tippers: slowly change the angle of the hopper to clot-bust

bumpers:make one or both walls of the hopper move in or out at least slightly to clot-break

shakers: repeatedly shake or bump the entire hopper to clot-break

stirrers: use a blade from below or above to stir or mix the hopper, clot-breaking