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Found 172 results

  1. It is with a little delay that I can present our Easter GBC module. This GBC module is an evolution from this old small ring module: (Brickshelf gallery of the old module here: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=569534 ) The module is quite simple. The wheel spins. The anti-jamming mechanism kicks in when needed and there are two inboxes to help place it optimally in a layout. There is a compartment in the base to store fragile objects during transport and the XL motor can easily be replaced: You can also use an M or L motor instead, should you not have an XL motor. The flowers are tulips: A daisy: And a daffodil: The design started with the head of the bunny, where I tried to make it both compact and cute: Brickshelf gallery with more pictures (once public): http://www.brickshelf.com/cgi-bin/gallery.cgi?f=569534
  2. Holy moly the GBC at Brickvention Australia was Huge. Brickvention if one of the largest Lego conventions in Australia, It's composed of builders from all over the country. This year the GBC team went above and beyond making a fantastic display. Rohah - The co-ordinator of the GBC walked me through all the different modules and explained what everything was. He was a fantastic speaker so all credit to him Without further ado, The Brickvention 2017 GBC!
  3. (Larger versions of any image available by clicking.) Although I find the whole concept of the Great Ball Contraption fascinating, I have to admit that I have not been particularly tempted to build one myself in the past. I can't say for certain why this was so, save perhaps that I saw too many versions of the standard conveyor built with tracks. Then Akiyuki started creating modules and posting YouTube videos and I was blown away. He has not only created some of the most mechanically complex LEGO creations ever, but he has managed to make them beautiful and mesmerizing at the same time. My favorite of these is the Ball Factory, a stunningly complicated mechanical creation powered by only a single motor. This model not only performs the standard GBC function of moving balls from left to right, but also integrates a similar system of moving buckets which is seamlessly integrated with the ball functions. See for yourself. Akiyuki's original video: I was enthralled by the video but figured I had a nearly 0% chance of ever reproducing this model without full instructions. Enter "The Rebricker", an AFOL who spent 2+ years reverse engineering this model and then creating a series of showing how to put it together. Beginning with his excellent videos, I spent about a month recreating the model in LDraw. This process of placing each part one by one resulted in my understanding of how the model works so that it was actually a reasonably simply matter to build it in real life. After completing the LDraw file I made a parts list and started putting together a bin of the required parts. While waiting for them to arrive, I made the cutaway render below in an effort to show how the model works. While this type of image may work with a typical model, you don't have to look at this image for very long to realize that this model is far too complex to understand with only a single image. Therefore, I'll divide the model into modules and go through the function of each of them one by one. The image below shows each of the modules color coded. Even with this level of subdivision, it is still difficult to see what is going on. Black = Main Power Distribution Green = Ball Spiral Lift Purple = Ball Lifter Gray = Ball Picker Lime = Ball Return Conveyor Brown = Ball Output Selector Blue = Bucket Wheel White = Bucket Loader Orange = Bucket Unloader Yellow = Bucket Conveyor Red = Bucket Shifter Tan = Bucket Dumper Balls start the journey at the input hopper and then are helically lifted by the spiral lift. After rolling down a small ramp, they are pushed onto a couple of pin joiners and then lifted and pushed into a 5 finger claw. The claw translates to the right and drops a pair of balls into a waiting bucket. The entire bucket wheel then rotates until it reaches a point that the bucket unloader lifts the bucket off the wheel and places it on a conveyer. The bucket is enqueued in the bucket shifter and shuffles along until it is dumped out. Depending on the position of the output selector, the balls are either passed to the next module or recirculated back to the input hopper via another conveyor. The empty bucket continues its journey by being lifted and placed back on the wheel. Like a wheel, the whole thing repeats and the cycle continues. To further simplify the functions, I've subdivided the model into three basic systems. The black parts are the motor (or crank) input and the main power distribution. The yellow parts deal with moving balls around, and the red parts deal with moving buckets around. The first module we'll discuss is also the simplest: main power distribution. The entire model is powered by only a single motor or crank. While driving the whole thing off one motor may seem unnecessarily difficult, it is actually the opposite. Because every module must be precisely synchronized with every other, a mechanical interconnection is required. The only alternative would be a maze of Mindstorms controllers and sensors, and it probably wouldn't work as well. Amazingly, when properly tuned the whole thing works with minimal effort at the input crank, and it is quite enjoyable to operate manually. If motorized, even an M motor is adequate. However, care must be taken to only rotate the input crank clockwise. Driving in the wrong direction will result in some disconnection and loss of synchronization at best, and at worst LEGO shrapnel all over the room. In my image below the input is shown in red and rotates at 1:1 with the motor. After passing the yellow idler gear, all the blue axles rotate at 1/2 speed. For ease of explanation, I'm going to assume that the input rotates at 600 rpm and make all my other calculations accordingly. (I know this is faster than a real M motor can turn, but this number makes the other calculations convenient for reasons that will become clear later.) This is 10 rotations per second. The blue axles therefore turn at 300 rpm. In every location where you see a green pinion gear, a function is driven from the backbone. You can see that all the bevel gears are braced by brackets and never skip. A skipping gear would be death since it would destroy synchronization. The most prominent feature of the model is the bucket wheel. This large wheel rests on a Technic turntable and consists of 16 platforms connected by #3 connectors (22.5 deg x 16 = 360 deg). It is very important that the movement of this module be intermittent. It cannot simply be geared to rotate at a constant speed. Rather, in must rotate 22.5 degrees and then stop, waiting for a bucket to be loaded or unloaded. This movement is achieved with the mechanism shown in orange. The 40 tooth gear connects to the backbone. The vertical axle rotates the disc. For 3/4 of the rotation, the 4x4 round corner bricks ride against the 3L blue pins on the bucket wheel and prevent the wheel from moving. The 1x2 panel then initiates motion and the end face of the corner brick completes 1/16 rotation of the wheel. Since the backbone is turning at 300 rpm here, after the 5:1 reduction of the 40 tooth gear the orange disc is turning at 60 rpm. Since the load wheel rotates 1/16 turn for each revolution of the disc, the load wheel is turning at 3.75 rpm. This means a complete revolution of the wheel happens every 16 seconds. Therefore, each bucket remains in position for exactly 1 second before moving on. (Now you can see why I chose 600 rpm for the input speed.) Some tidbits about this module: Because there is 4L axle between each connector, this is not a perfect 16 sided polygon and there is a small bit of stress in the connectors. The orange disc in one key part that cannot be rotated backward or it will jam against the load wheel. I took apart my turntable and added some silicon spray to make it turn more smoothly. At any given time there are only 12 buckets on the wheel; the other 4 positions lie between the bucket unloader and the bucket loader. The wheel rotates counterclockwise. When a filled bucket reaches approximately the 3 o'clock position, it is lifted from the bucket wheel by the bucket unloader and placed on the bucket conveyor. This is much easier said than done. The claw which grasps the bucket must perform a carefully choreographed dance in which it translates radially inward to grab a bucket, then lifts it, then translates in radially outward to lie over the conveyor, then sets it down. This means that both a radial and a vertical motion are required, and they must be synchronized perfectly. The claw is shown in blue. The spacing of the jaws must be adjusted such than they just grasp the tapered sides of the bucket. The entire claw moves radially on the yellow carriage. The yellow carriage also translates up and down when pushed by the orange lift assembly. Vertical motion is driven by the orange lift assembly. The 40 tooth gear is driven by the backbone and turns a 3x3 crank. This crank pushes against a 7L lever. Note that the crank holds the lever in position for 1/4 revolution before releasing it. This lever drives a pushrod which turns a 4x5 L-shaped crank. The crank then pushes against the yellow beam to lift the carriage. The maximum height of the lift can be adjusted by changing the length of the pushrod. The yellow carriage slides up and down on the vertical axles, and carries the blue claw with it. Only gravity returns the carriage back down when the orange crank moves out of the way. Sometimes the axles can be sticky and the carriage does not go down right away. The red gear system controls radial motion of the claw. The 40 tooth gear is driven by the backbone and turns a 3L liftarm crank. This crank uses a pushrod and lever to rotate a 36 tooth gear. The 36 tooth gear drives a 12 tooth gear which is connected to a crank driving the vertical red axle. This red axle drags the blue claw along the yellow carriage. The goal is to move the crank +/- 90 degrees which is why the 3:1 reduction of the double bevel gears was needed. Although the purpose of the red mechanism is only to move radially, it also moves up and down as the crank swings through its arc. For this reason, the vertical 8L axle must be able to slide through the holes on the blue claw. Some tidbits about this module: The 40 tooth gears each rotate at 60 rpm which means the unloader cycles at once per second, perfectly synchronized with the bucket wheel. It must be carefully tuned to pick up a bucket only when the wheel is stopped, and to be out of the way before the wheel starts moving again. It must also deposit the bucket on the conveyor and allow the conveyor to whisk it away before moving back toward the wheel. The bucket conveyor is among the simplest mechanisms in the machine. It is not driven off the main backbone, but actually off one of the bucket shifter axles which has already been reduced 5:1, therefore the long drive axles turn at 120 rpm. The bucket unloader deposits the buckets on the yellow conveyor which then moves them to the green conveyor. At the far end of the green conveyor, the bucket shifter grabs the buckets and moves them off. While this module doesn't need to be synchronized to be in a particular phase with the other modules, its speed is very important. It needs to deliver exactly one bucket to the bucket shifter each time the shifter moves or a queue of buckets will develop. The speed of the conveyor and overall number of links is therefore critical. Some tidbits about this module: It is important that the yellow u-joints be clocked in phase with each other so that the movement of the yellow conveyor is smooth. The yellow conveyor is 1 plate higher than the green conveyor to help with transferring a bucket from one to the other. A small guide had to be added above the transition (visible in the render) to prevent the corner of a bucket from getting stuck in between. At any given time there are usually 3 buckets on the conveyor. The bucket shifter takes buckets from the conveyor and moves them toward the bucket dumper, eventually driving them into the arms of the waiting bucket loader to go back on the wheel. The spacer shown in black has slots for 5 buckets, and there is often also a bucket to the left of the leftmost slot. This mechanism needs a complex motion consisting of both side-to-side and front-to-back movement.It must move the buckets to the side, then shift back out of the way and translate back to its starting position without touching any buckets to start again. The whole things is driven by the apparatus shown in yellow. The 40 tooth gears are driven by input backbone and therefore rotate at 120 rpm. Each drive a chain system consisting of 23 chain links and a single tread link. When they get to the right point in their cycle, the tread links push the red and blue carriages in and out via the vertical 5L beams. The red carriage controls front-to-back movement of the spacer and the blue carriage controls side-to-side motion. As the red slider shifts back forth, it drives a pushrod moving a Z-linkage (the pink pin is ground). This Z linkage slides the red carriage front-to-back on the blue carriage. The black spacer is supported on the red carriage. Note the axle on the red carriage which must be able to slide through the top part of the Z-linkage. This all has to be kept perfectly square to avoid friction. As the blue slider shift back and forth, it drives a pushrod moving an L-shaped crank (the light blue connector is grounded). The side-to-side motion of the output of the crank translates the entire blue carriage side-to-side on fixed axle supports (not shown). Some tidbits about this module: Because 24-tooth gears drive the chain, and because the chains have 24 links, you might think that this would make the bucket shifter operate at 120 rpm. This would be a problem because it would deliver 2 buckets every second instead of one. However, remember that each chain link is actually made up of two cross braces (or teeth), and therefore this extra factor of 2 gives us 60 rpm (one per second). The placement of the track links on each chain must be precisely synchronized. If a link were trying to move a slider left and the same time as another link were trying to move it right, the mechanism would destroy itself. This mechanism cannot be run backward. The track links jam against the sliders. The bucket shifter must be timed to align perfectly with the bucket dumper and the bucket loader or buckets will be thrown on the floor or, worse, down into a mechanism. At any given time there are 5 buckets in the bucket shifter. The bucket dumper picks up a bucket from the 3rd position of the bucket shifter and dumps the balls into a waiting hopper. It then deposits the bucket back into the bucket shifter. It must accomplish all of this during the tiny amount of time that the bucket shifter is stopped, about 3/4 of a second. The white 40 tooth gear is driven by the backbone. It turns a 3L crank which drives a vertical pushrod driving a 4L crank. This is connected to an inverted V-shaped linkage. Two different motions are possible when the V-shaped linkage is rotated. Since the far end of the links is attached to the green carriage, the green carriage can be driven along the purple sliders. However, if the green carriage encounters an obstacle (like a bucket) or if the green carriage bottoms on the end of the track, then motion of the white linkage rotates the whole purple assembly up around the exposed axle on the right. This whole system results in a 4 stage motion. First the green carriage moves to the right to grab a bucket, then the purple assembly lifts and tilts, then it comes back down, then the green carriage releases the bucket. All of this motion occurs in response to the continuous rotation of the lower white crank. Some tidbits about this module: Because the white gear rotates at 60 rpm, one bucket is dumped per second. The bucket dumper must accomplish its job during the tiny amount of time that the bucket shifter is stopped, about 3/4 of a second. The purple 3L axle sticking out at the left of the image is a down stop to prevent the purple mechanism from pushing down on the bucket shifter and jamming it. The final part of the bucket system is the bucket loader which accepts buckets from the bucket shifter and places them back on the wheel. This module has the most complex motion of any of the bucket system because it must translate, lift, and rotate all in a synchronized fashion. The claw starts by facing the bucket shifter which pushes a bucket into the empty claw. The claw then simultaneously lifts, rotates 90 degrees to face the wheel, and translates toward the wheel. When it reaches the wheel, it moves down to deposit the bucket and then pulls back out the way to begin again. The first part of the system is the "quick return mechanism" shown in orange on the lower right. The 40 tooth gear is driven from the backbone and drives a crank arm made from cams. This crank arm moves a 9L lever back and forth. A long pushord then connects to a 4L crank arm at the other end. This crank is geared up 2:1 to allow a +/- 90 degree movement of the vertical orange arm. This arm drives the white carriage toward or away from the bucket wheel. The white carriage slides on a pair of fixed axles (not shown). When the carriage is away from the bucket wheel, it needs to rotate 90 degrees to point towards the bucket shifter. This rotation happens passively without an active mechanism. The L-shaped 3L black liftarms at the bottom of the claw contact the curved dark gray brick and drive the rotation at the right point in the cycle. The brown mechanism controls vertical motion. The 40 tooth gear is driven by the backbone and drives a 3x3 crank. This crank presses a lever for 1/4 of its revolution. The lever lifts a pedal which is under the black claw, lifting the whole thing. Note that the black claw must be able to slide through the white carriage as it raises and lowers. Some tidbits about this module: When the orange quick return cam connection is at the bottom of the lever, near the pivot, the lever moves slowly. When the cam connection is at the top of the lever, away from the pivot, the lever moves quickly. This allows for slow movement of the claw when a bucket is held, preventing dropping the bucket. But return of the claw when empty happens quickly. If the speed were made uniform over the whole cycle, the claw would move too fast when holding a bucket and drop it. The jaws of the claw can be adjusted to provide exactly the right spacing to lift the buckets. The bushings at the end of the orange pushrod can be adjusted to give exactly the right rotation of the crank. Every portion of this mechanism has to be perfectly timed to synch with both the wheel motion and the bucket shifter motion. The whole module runs at 1 cycle per second, just like the other major assemblies. Now we'll move on to the ball systems. The balls start the cycle in one of two hoppers, either coming from an upstream module or being recirculated from the ball factory. Both hoppers feed the bottom of the spiral lift. The spiral lift functions very simply by rotating against a set of fixed ribbed hoses. The lift drum has 6 flutes each of which can trap a ball and roll it up the spiral. When a ball gets to the top of the spiral, it bumps against a slope which knocks the ball into a nearby ramp. At first it might seem that this module does not need careful synchronization like the other modules, but this is not the case. The module must deliver balls at the same rate as the machine consumes them or it will either form a queue (disastrous) or fall behind (annoying). Unlike the other modules, this one is not driven by a 40 tooth gear from the backbone but by a 24 tooth gear. This means the input axle rotates 3 times slower than the backbone or 100 rpm. A further 5:1 reduction means the drum is rotating at 20 rpm. Singe the drum has 6 flutes, it is delivering 6 balls per revolution for a total of 120 balls per minute, 2 per second. Every bucket takes two balls, so this works out perfectly. The ball lifter accept balls from the spiral lift and pushes them up into the waiting jaws of the ball picker. It operates on two balls at a time. A pair of balls roll down a ramp and drop in front of the blue pusher. The pusher moves them forward and they drop into the recesses of inverted Technic engine cylinders (not shown), a unique parts usage if ever there was one. The white pin joiners, now centered under the balls, then push them up. The red 40 tooth gear is powered from the backbone. The attached 3L crank pushes down on the red pedal which pivots on the central pin axis. The other end lifts the white ball lifter. The white lifter motion is very simple, moving in a guided vertical direction. The blue 4 bar linkage is slaved to the same 40 tooth drive gear. A 2L crank pulls down on the vertical blue axle which pivots the ball pusher forward while it remains level. Note that it does not return via the red powered input, rather a counterweight pulls the ball pusher back to starting position. Some tidbits about this module: The ball pusher could work without the counterweight, but then the system would have to lift the balls and move the blue pusher at the same time. By using a weighted return, the drive system doesn't have to lift two things at once. This reduces power demands on the system. The red gear turns at 60 rpm which means this whole system operates at one cycle per second (two balls per cycle). The lifting and pushing functions have to be perfectly synchronized. The ball picker is a fascinating contraption. It receives balls from the lifter and moves them over to the wheel and drops them into a bucket. the yellow and orange system control horizontal motion and dropping, and are interconnected. The yellow system is driven from the orange 40 tooth gear off the backbone. The 3L crank drives a horizontal pushrod which in turn rotates a 2x4 crank. A connected 4L crank lifts the vertical yellow beam which turns the 36 tooth gear. This is then geared down 3:1 to achieve a +/- 90 degree motion in the final crank. This crank slides the claw along a track made from 12L axles (not shown). Because the crank also goes up and down, it needs to be able to slide along the vertical claw axle. The orange system drops the balls. The claw is spring loaded shut via a rubber band. When the balls are pushed up by the lifter, it drives the jaws apart slightly which then grip and hold the balls. The light gray arm at the bottom right of the claw must be pushed to open the 2 forward jaws and drop the balls. The orange 3x5 L-shaped beam provides this pushing motion. It is driven through a fairly complex linkage by the input 40 tooth gear. There is a towball on the gear which pushes a lever, bumping the 3x5 beam to open the jaws. Some tidbits about this module: The length of the final yellow crank can be adjusted to control the endpoints of the claw. The claw deposits 2 balls per second into a bucket. A large counterweight is used to make sure the ball dumper is never engaged while the claw is translating or the system would jam. It is also needed because the towball can only push and not pull so there is no other return mechanism for the orange parts. The simplest of all modules in the ball output selector. This is not part of Akiyuki's original design but was added by The Rebricker. When the balls are dumped out of the buckets they hit this angled plate and can go either left or right. Tilting the plate right rolls the balls down a ramp and dumps them overboard to a downstream GBC module. tilting the plate left rolls the balls down another ramp to the return conveyor. Having this selection available allows use of the ball factory either in a larger GBC setup or in recirculation mode as a self contained module. I don't know the function of the Plinko style pins on the platform, but they look kind of cool. The ball return conveyor was added by The Rebricker to allow use of the ball factory in recirculation mode. It accepts balls from the bucket dumper and returns them to the input hopper. Because it travels up a significant slope, it cannot just use tread links because the balls will slide down to the bottom. A series of 7 cleats are made from 1x3 plates and tiles and affixed to every 11th tread. Each cleat carries 2 balls, and the timing works out nicely such that no queue of balls is produced. Now that you know how the whole thing works, what is it like to actually build this thing? I found it a real joy. None of the building techniques are very complicated in and of themselves, so the actual assembly is pretty simple if you are following the videos. The timing, on the other hand, is another matter. In some cases, being off by a single gear tooth is a problem, so every module has to be synchronized with every other. I found this process enjoyable, but others may find it frustrating. You won't see an official LEGO set anything like this. Let's take a look at the massive pile of parts. There are about 3100 parts here, but note that no motors are technically required so the cost does not have to be super high. Although this is a technical model, most of the parts are still standard bricks and plates. Here are all the modules built and arrayed on a table. At this point I had already completed the build and run the factory for a few days, but I found that sometimes a ball would drop down inside. The studs of the base plate would hold the ball and make it very hard to extract since the access is so limited. To combat this problem and also to improve appearance, I added 1200 tiles to make a tile floor. It worked great on both fronts. In all I spent a couple of months building the LDraw file, collecting parts, building, and troubleshooting. My family has never been so fascinated in watching a LEGO creation, and that's exactly the reaction I was going for when I decided to build this. The build is not for the faint of heart, so I recommend it only for those who feel the technical achievement is worth the effort. But if you are one of those people, this is as good as it gets.
  4. Hi Everyone. I'd like to show you my GBC Module that I made called "To and Fro". Definition: to and fro /ˌto͞o ən ˈfrəo͝o/ adverb - in a constant movement backward and forward or from side to side. verb - move constantly backward and forward. noun - constant movement backward and forward. I wanted to design a GBC module that I hadn't seen done before. The main feature of this design uses a string and pulley system, with different levels of mechanical advantage implemented to get the timing of the mechanisms just right. This GBC module adheres to Type 1 of the GBC Standards, processing one ball per second on average (http://greatballcontraption.com/wiki/Standard). The main focus of this module is the 'ladder' in the middle which raises and lowers using string and pulleys. You can see this in the video between 1:48 and 2:04, and I'll try to describe what is happening. First of all, the end of the string is attached to the frame, and goes down to the cranks. The exact length of the string can be adjusted, similar to how guitar strings are tightened. The cranks have pulleys on them, so the string actually moves twice as far as the diameter of the cranks as they rotate, but at the same time the force is halved. Next, the string goes up to a pulley fixed on the frame, then down and around another pulley, and back up again. The bottom pulley is attached to the moving part of the 'ladder'. This halves the distance that the 'ladder' moves compared to the string, but also decreases the force required to do so. The string goes over another static pulley at the top, and then back down to the outside edge of the moving part of the 'ladder'. To move the outside edge of the 'ladder' requires the full force of the string to move. Due to the mechanical advantage of the different parts of the pulley system, the 'ladder' wants to move up first since this takes less force, but once it hits a stop at it's upper limit, the string then provides force to the outside edge of the 'ladder' which causes that last little 'kick', which lets the balls roll to the other side. This module can also be broken down into four smaller sections for easier transportation: The motor which is part of my Automatic Motor Shutoff and Alarm System, The 'hopper' and 'ball diverter', The 'ladder', and The 'waterfall'. There is only one M-motor powering this module and that helps ensure the timing of each section is in sync with the next. The motor section is attached to the 'ladder' section with a universal joint, and the 'ladder' section is attached to the 'hopper' section with a CV joint. The 'waterfall' section doesn't need any motor input, so it is attached to the 'ladder' section with a single axle that allows it to be detached easily. Between the 'ladder' section and the 'hopper' section is differential (hidden away underneath), and I can manually adjust the rotation of this differential via a worm gear to get the timing between each section just right. Apart from this one worm gear used to make timing adjustments, I haven't used any other worm gears as I have seen the damage they can do to GBC modules if something gets jammed (although, in theory, my Automatic Motor Shutoff and Alarm System should stop this from happening anyway). There are quite a lot of gears within the drivetrain, but it runs quite smoothly. When I was creating it I thought the weight of the 'ladder' would cause a lot of strain on the motor, but when one side is going up gravity is making the other side go down which cancels out a lot of the strain. Jams sometimes occur in the 'hopper' and 'ball diverter' sections, and are typically caused by too many balls in the hopper, or the timing of 'ball diverter' not being adjusted correctly. I have had this running at a public expo that my LUG held, but I was too busy to baby-sit this module, so it was only running part of the time, but when it was running it ran without issue. This is the first GBC module that I have made, so I spent a lot of time trying to get it working consistently. I hope you like it. Any constructive feedback/comments/questions are welcome. UPDATE: I have created an LDraw/MLCad file of my GBC module. Read more here. Music:
  5. For some time I have been trying to develop a mechanism to allow intermittent rotation for various GBC modules I have built or plan to build. A Geneva mechanism would be ideal but its not easy to build using Lego, and some solutions are quite large. I have developed a fairly small version which uses a rotating arm to intermittently turn the black gear with 4 rollers. Indexing is acheived by using a 24T gear with four blue pin/axles. As the wheel rotates and drive arm disengages the 24T gear & wheel is held stationary by an arm kept in contact with two of the blue pins by a shock absorber with a soft spring. I tried using knob gears but due to them being slighty smaller diameter the indexing is no longer exactly 0, 90, 180, 270, degs. The two black 36T gears are only used to hold the rollers and drive arm as along with the 24T gear as they are the only lego parts which 4 equally space holes in line with the axle hole. At the moment the output axle stops every 90 degs but could be made to stop at 180 degs if use a 12T gear meshed the the 24T indexing gear to give a1:2 step up. (An alternative would be to use a 20T meshing with a 40T gear holding the drive rollers.) Hope that makes sense. Timings should be adjustable via varying the drive input / output gear ratios and choice of PF motors. Video will make it clearer how it works. Next step to try and make it more compact and see if I can use it for my build of DaFokka's Ballkirk Wheel GBC Lift.
  6. I have been shamelessly plugging the Lego Technic 42042 Crawler Crane over in the "What should I buy" thread here at Eurobricks but I just came across a new reason to buy it that I thought was relevant to a more general audience. A company in Europe called PV Productions has created a C-Model that is a GBC contraption. (No relation, ownership nor knowledge of who they are.) calls it a D Model because he has two GBC C models created from the set, but only the D Model is available for purchase now... and purchase it, I did! My seven year old son is into small Lego Techic models as he doesn't have enough patience to build the 1,000+ piece models, but after showing him the video, he wants to build it with me this weekend. Only problem... I don't own any of the Lego soccer or basketballs that are used for GBC models and I have no desire to pay the crazy $2.50+ costs per ball!! I've attached a video below (I assume that's okay) to the Youtube video he created of the D model. I'll be picking up the C-Model as soon as it's available for purchase. He also has pending future GBC models for sales that are all C Models of 42043, 42054 and another that is a 2 set C Model but I cannot recall which... Watch the video and you want to buy the set and want to figure out how to buy some Lego balls or alternatives. If soeone has a good recommendation for an alternate source, I would love to know it. Update: just checked my Paypal receipt and the PV stands for Phillip Verbeek, I think.
  7. PV Productions now have instructions for a C model LEGO GBC 15 – 7 Modules – 42055. Looks good. http://pv-productions.com/product/lego-gbc-15-42055-building-instructions/
  8. My eBay order of 14mm beads arrived in the mail from China today. Big thanks to EyesOnly for providing the eBay link. They costed about $5 USD. Since I have a few Lego balls, I thought I do a comparison. Here is a picture of the recent Lego balls from Friends sets and the Chinese bead on the right. As you can see the bead is shinier and smoother than the Lego balls. Also the bead has a bigger hole that goes all the way through for the strings. The hole in the Lego balls do not go all the way through, therefore, you can't make a necklace or bracelet out of them without drilling. With the bigger hole there is probably less mass. I weighed 8 Lego balls and 8 beads. 8 Lego balls = 12 grams 8 beads = 11 grams The slight weight difference didn't seem to cause a problem with my ball accelerator module since I am not flinging the beads that far. GBCs that shoot long distance may need some testing and adjustments. There is also a size difference with the beads. They don't have the exact size consistence as Lego when measured with a caliper. Lego ball = 14.07 mm beads = 13.5 to 13.7 mm In general, they seem to work well with my 4 GBC modules. One issue I found with the bigger hole is it can create a flat spot that the beads can't roll over if it doesn't have enough momentum. Some of my GBCs uses incline with gravity to feed and the beads some times get stuck until another bead knock it loose or I manually free them. Summary. At 5 cents USD each, they are a bargain compared to Lego balls. They are lighter than Lego balls and the bigger hole can cause the balls to get stuck on the path. So more 'babysitting' of the GBC module may be required. Overall, I think they are great for doing public display of GBCs where balls tend to get lost throughout the day.
  9. The pump and anti-jamming mechanism of the Yellow Submarine worked so well that I had to make a module just focusing on these parts: Here are the building instructions: http://c-mt.dk/instructions/lxf/gbc_pump.lxf Here is the thread for the Yellow Submarine module: http://www.eurobricks.com/forum/index.php?/forums/topic/146542-gbc-yellow-submarine/ It is fun making GBC modules. Now I just need a good idea for the next module :)
  10. Hi gbc fans, i have noticed over the past few months that quite a few gbc topics have been created, I have been finding it hard to find them in amongst all the model team stuff. Do you think we should have our own gbc subtopic so it is easier to find everything relating to gbc? thoughts?
  11. Here is a GBC mod of the LEGO Ideas set 21306 Yellow Submarine with The Beatles! The XL motor runs on speed 1 or 2 (both will do, but speed 2 is better at handling batches of 50+ balls) A closeup of the mechanism from outside: I'm quite satisfied with how well the "anti-jamming" mechanism works. I intend on making a separate module with all themechanism exposed so it's easier to see. But for now. Enjoy the Beatles :)
  12. Having used 12 pce BWE gear qaudrants for two other MOC's I had two left over. These have been used as support guides for a ball lift module using the large Lego Chain links which have studs Clearances for the lift arms is tight but with carefull setting up works well, still some work to do to improve the ball loading hopper which is too high at present. IMG_4244 by Doug Ridgway, on Flickr IMG_4243 by Doug Ridgway, on Flickr Video:
  13. Hi. With the quality of entries I've seen so far, I don't like my chances of winning, but it would be nice to get a badge! I'm going to use this contest as an excuse to redo a previous model of mine - a GBC module powered by pneumatics. This is what the old version looked like: I have used it in a previous display, but it has numerous shortcomings as a GBC module. The output is not in line with the input, violating the spec. It was what I needed at the time, but it's not suitable for general use. The output is impolitely high. Again, it was what I needed at the time, but I couldn't put this into a normal circuit. It would frequently jam. It spilled lots of balls. I will be using the same sequencing (basically the simplest alternating sequence possible). I had toyed with the idea of something more complicated, but 1) I couldn't get my head around how to make the sequence I wanted, and 2) it would have been too slow anyway. I probably won't make a compressor for this one, leaving it hand-operated. The idea being that in a display it can be somewhat interactive - the audience gets to power the Contraption (or at least some portion of it). Best of luck to all entrants! Owen.
  14. I have recently become interested in the art and science of GBC and I am looking for the best way to start building. One problem though, I don't like to mix my sets . I have seen some great GBC c-models (such as https://www.youtube.com/watch?v=lb5kTm9Ykn0 ) but unfortunately haven't been able to find any instructions. In particular I am looking for simple GBC modules made of single sets to study the entire GBC mechanic and learn from it to make my own modules. It doesn't really need to be fancy or cool, just functional and c-model-ish. Has anyone come across something similar? It seems that in all topics I've found, the possibility of making modules as c-models of existing technics sets isn't really discussed.
  15. As I am packing to move to my new house, I am forced to take stock of my current collection and conclude that it is ridiculous. I've disassembled a number of old Technic sets and a few Technic MOCs, but in particular I went overboard on building Akiyuki GBC modules. I've chosen a few of them to get rid of, but rather than just part them out I thought I would offer them up to see if anyone is interested. I could take them apart and ship them or, if someone is close, they might even want the custom display cases I built! Here is a list of those that will need to go. If anyone is interested in making me an offer, please contact me by PM. Elevator Lift Triggered by a Stuck Ball Zig-zag Lift Catch and Release I had already previously parted out two others, but if anyone wants them I probably still have the parts. Pneumatic Module Fork Module
  16. For Brickfete 2016 and the Friends contest, I made a Friends-ly tree slide GBC module. The input and output are to GBC standards so it should play nice with other GBC modules. During the event I had make various modifications and fixes. Although, it worked great at home. I think I got the bugs out of it now. It had pretty good response and feedback from girls and moms. LEGO Friends Tree Slide GBC Module by dr_spock_888, on Flickr Watch the balls climb up and slide down.
  17. Today I would like to share my latest GBC module with you. It is a Quincunz, also known as a Galton Board. The balls are being transported up with a conveyer belt and a light sensor counts how many balls have passed. The balls then roll down the board and at each peg they can either bounce left or right. After the last peg the ball is caught in a repository. Once 100 balls made their way down, the gate opens and releases all the balls. Probably no GBC module could deal with 100 balls at a time, so I queued them up and deliver them one at a time. More information and the math behind it is available.
  18. LEGO Friends Wheel Bucket Excavator Great Ball Contraption - the Friendly WBE way to move GBC balls It has been a while since I've made a GBC module. This is something fun for the LUG's upcoming event season. I've been sitting on an idea to use those "scoop" pieces in a GBC for a couple of years. The upcoming BWE finally kickstarted my bum to action. It took some trial and error to get them to work. I may have to do more tweaking once it starts going to events. As GBCers know, what works great at home, does not outside the home. Wheel Bucket Excavator GBC by dr_spock_888, on Flickr I still have to make a suitable ball receiving/loading bin. I am not sure the events GBC coordinators will let me use the lid from a take out order of french fries.
  19. My new GBC Module(s). These are actually two modules working together,both using the same motor. The tricky part was to sync everything up - making the motor switch the cart direction just when it reaches it's extreme. Everything stays in sync without any drift (tested for ~2 hours,stays in perfect sync) The motor always spins in the same direction. Here's the video Thanks for watching! (It's very hard to name GBC modules )
  20. Looking for another GBC to build I downloaded the excellent instructions by Paul Verbeek for building his GBC # 5. This was built as per instructions but as I only had one 40T gear I had to use for the 1st stage reduction a 36/12T gear combination, giving an overall gear reduction of 15:1 instead of 25:1. Many of my studded parts are quite old & worn. When the contraption was run the increased cycle rate caused it to fall apart !! Decided to build a stud-less version and eliminate the double gear reduction which was replaced by a simple 24:1 worm gear unit directly driving the crank arm. Instead of using the ball loading device shown in the instructions I used the same ball loading gate as used on my GBC #1 - Bucket Wheel Lift. Getting the trip lever geometry right took a lot of attempts to perfect ! Ball return run is only temporary until I build a 4th module (vertical lift ?) and link them all together. The only non lego part is the 56L x 28L base plate by Play BLOX from Wilco at £3.50 - approx 1/4 equivelant lego price. See video which is best with sound Off. [m.e.d.i.a.] [/m.e.d.i.a.]Doug
  21. Great Ball Contraptions are fascinating and I designed two GBC modules that use LEGO slides for getting the balls up and down. The first uses a ball pump to push the balls up through the tower. The balls then roll down a double helix: The second modules uses the double helix for an Archimedes Screw. This is a very effective method of lifting balls up.
  22. Captainowie

    [GBC] Kicker Module

    Hi guys. I have begun construction of my newest GBC module, and I've decided to try sharing my journey with you. I am aiming to make a projectile launcher, that will get the balls across the gap between two tables, a distance of about one meter. I have considered two approaches: contra-rotating wheels as in a bowling machine; or impact from a moving lever, like someone taking a golf shot. After an afternoon playing around with contra-rotating wheels, I decided that the moving lever had more chance of success. As most of my structural elements are currently tied up in display models and other GBC modules, I decided to use the one set I have that isn't either built or assimilated into my collection - a 8110 Unimog (no longer MISB because I had already raided it for the pneumatic pump). As a result, I would like to see if I can make this from only the parts in this set - because this wasn't going to be hard enough already! Here's a very quick rendition of what I've got so far: The part on the end of the arm is the rubber 2-length liftarm, because I thought it would make for a gentler impact on the balls. I plan to raise the balls vertically into the path of the arm just like they do at some driving ranges. In order to get a rate of ~one ball/sec I'm probably going to have to build two or maybe even four of these things side by side. I do have a couple of questions I'd like to ask the forum: When using shocks like this, should I stop the movement of the arm before the shock expands fully? Or will the shock handle the sudden stop by itself? Has anyone built a reliable projectile module that shoots over such a large distance? I don't remember seeing one online anywhere, though I've seen plenty that cover smaller distances. I fear that at this range precision is going to become an issue. How should I prime the arm? I need to allow for quick release, and automatic re-arming. Is there any other mechanism I should consider? Like perhaps a centrifugal gun? I'll keep you all updated on how I progress. Owen.
  23. Saw this video today.... Just had to post. Simply amazing. Honestly, I post as a potential GBC in Lego jocularly. Not sure all elements in Lego can behave in such a manner as to make this possible. But what fun if it could! Would be another great group project.
  24. As can be seen in the movie, this screw can't be reversed - balls are always transported forward regardless of rotational direction. A very simple mechanism. The time consuming part has been making it sturdy. Had to rush the design at the end to finish before an exhibition, so some things will be adjusted later. I intend to post a picture of how it's constructed when the 3D model is finished. The switch is purely mechanical using regular transmission parts. Driven by a medium motor.
  25. here is an unfinished entry for the contest, photos to come soon 9v system