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Found 224 results

  1. This is my first creation with the Robot Inventor set, 51515-1 , created in stud.io using LDraw parts as custom parts. I hope you like it and it inspires you to build. The PDF building instructions and part list are available at Rebrickable for free. I haven't build it myself because I do not own the set, but greg10 did and posted a photo. In LEGO Studio the motor cables are not available so; I recommend to use the 49283 Wire Clip with Axle Hole (also available in the set) to manage them so that they will not end up in the wheels.
  2. I did program something with two "own Blocks" wich work together, but for that I need to check if the text entered in the text parameter of the first block matches the one of the second block. Basically I need to know how to check if "Text variable one" matches "Text variable two". Please comment if you know how to do that, or if you have any good alternatives, currently I use numbers, but that's hard to keep track off. Edit: I program in Mindstorms Ev3 with the Ev3 brick
  3. For delivering the candies to the visitors, we use four lockers. The ticket you have received at the beginning, is used to open the locker containing your own candy. The current version uses an iris-like mechanism, you can see it in the picture (click on it to see it on Youtube in action): I am planning to upgrade the lockers to a new door mechanism, the so called torggler doors. It is named after its inventor Klemens Torggler. Below you find a Youtube video containing the first proof of concept. The mechanism will be improved in the coming weeks. Stay tuned! Enjoy, Hans
  4. Did you know that any standard EV3 brick is capable of controlling the LEDS separately? And that the display is capable of displaying 4 shades of gray? No, this extra functionality is not available via the standard programming environment that Lego provides. But if you use low level programming (I used EV3DEV in combination with C++), you have. See the example below. You can read my article at our blog here: https://siouxnetontrack.wordpress.com/2020/04/25/lego-mindstorms-ev3-with-an-image-with-4-different-shades-of-gray/ Or have a look at the Youtube videos. Enjoy. Hans
  5. This lego GBC module uses the lego Mindstorms EV3 to power the module. It uses a robot arm style mechanism to lift the balls from the previous GBC module to the next one. It is quite reliable and has had almost no issues while I have been testing it. It is quite simple and small for a mindstorms GBC module but it is the first thing that I have ever made and programmed with it. (Do you recommend using the EV3 programming app or Python? I know Python quite well but have not tried using it for mindstorms before) I think it turned out ok for my first MOC using mindstorms, hope to make the next one much more interesting :) Instructions. Photos on Flicker.
  6. Motorized model of a crawler crane with Mindstorms EV3. Features driven tracks, and superstructure functions controlled by an automated distribution gearbox. Functions/features: Driven tracks Boom elevation Boom extension Winch Superstructure rotation Ever since TLG released the rotary catch pieces from the Bugatti set I sought to incorporate it in a distribution gearbox so that I could control 4 functions with 2 motors. However, I did not want the play experience to be constantly interrupted by shifting the gearbox. For instance, if I used PF and installed a stepper mechanism to control the gearbox, I'd constantly have to count how many "shifts" I've done to ensure the right function is engaged. With that in mind, I realized Mindstorms EV3 is the perfect solution to this - by simply utilizing a touch sensor, the mechanism can detect how far the shifting motor has rotated thus automatically selecting the right function. The gearbox, which sits at the heart of the superstructure, features a cam attached to the shifting motor to hit a touch sensor. When a command is received from the remote, the shifting motor rotates until the touch sensor is pressed, then the EV3 tells the shifting motor to rotate a certain number of degrees to select the corresponding function. This utilizes a switch/case for the remote, and because it features up to 11 button combinations all superstructure functions are controlled from the same channel (channel 2 on the remote). This gives controlling the model a very natural feel, and sometimes I even forgot that I was controlling a distribution gearbox because the EV3 shifts it so seamlessly. As for driving, it too uses a switch/case for the remote. Because it's just a simple tank drive, the commands for this are much more straightforward compared to the gearbox functions. Driving is controlled from channel 1 on the remote. Additionally, there are sound effects that play while operating the crane. Pressing the left two buttons together in the 1st channel starts the engine (thus starting the program), and pressing the right two together stops it (thus ending the program). Because the PF IR remote uses levers instead of buttons, this effectively makes the model inoperable with only a PF remote. The EV3 remote feels more natural for controlling this model too, as some superstructure functions (boom elevation and superstructure rotation) involves pressing two buttons simultaneously. In the end, I'm pretty satisfied with how this model turned out. I was initially worried that this gearbox I had in mind won't work as smoothly as I imagined, but it turned out to work flawlessly. It often made me forget that I was even controlling a gearbox as the EV3 does the shifting for me. Of course, there's still areas that could be improved - for instance, the boom extension and winch operate pretty slowly. Not using a worm gear in those mechanisms probably would've helped, but that would mean the mechanism becomes "unlocked" as soon as the gearbox disengages it. Occasionally the gearbox would jam, making me restart the program, but overall the finished model met my expectations. Video: Photos:
  7. When I was building the Robot Arm (see my mail thread here), I stumbled upon the ABB robot flex picker (also known as a delta robot). I was amazed about the simple construction and how fast it can work. Although I am definitely not making the first one of Lego, I wanted to build my own version of it. In this thread you can follow the work in progress. I have now build the base and the three arms that will support the grabber. The grabber will be able to pick up the candy containers and move them to a different location. Don't know yet what its place will be on the layout, but I am confident that it will have its use. Photos can be found at Flickr, click on the picture below to see some more pics and an animated gif. Please let me know that you think of it. Enjoy, Hans
  8. Two years ago I presented you my first pinball. Today I want to show the second version, with changeable boards and an interactive Mindstorms board. If you like it please add your support on LEGO Ideas page https://ideas.lego.com/projects/4025655b-7b86-4aeb-bc91-57aa33c862e7
  9. Summarizing: - WeDo 2.0 - Spike Prime - Mindstorms Ev3 I believe that, since their introduction, automation and then coding were supposed to represent the natural evolution of Technic,however they ended to be confined in the educational niche. Moreover, wouldn't have been better, on a marketing level, to avoid the fragmentation in three themes? I understand that there are different ages and costs but I think that Lego could have stuck with only one sub-brand, whatever it was, then proceeding to diversify. A single sub-brand would have increased the exposure, hence the sales. Confusing marketing, wasted opportunities.
  10. In case you have missed my earlier posts: the article below is part of the large, fully automated train layout called "Sioux.NET on Track". You can watch a video of our presentation of our layout at Lego World Utrecht 2016 at our Youtube channel: Replacement of a slow candy crane As you can see in the video, the loading of the four wagons is done by the so-called candy crane. A nice and eye-catching structure, but is is slow. Really slow. When the visiting parents asked me at Lego World what the layout was about, my answer was usually “for children it is a candy delivery machine but for the parents it is a Zen machine” ;-). The delivery of four candies took in total about 13 minutes; most of the time the candy crane was fetching the containers with candies and loading them into the train. When we walked around Lego World, we noticed the following robot arms at the Mindstorms stand. We all had the same idea: that robot arm would be our next building and the replacement of our crane. The robot arm would be responsible for moving the containers from the pickup position to the wagons. The robot arm on the photo is originally designed by Mike Dobson and a LDD file is available. But I don’t find it a challenge to build these things from a building instruction (although, rebuilding these large objects from an LDD file is quite a challenge in itself ;-). So I started to build a robot arm from scratch. Of course, you will see some parts that look similar and yes: I have stolen these ideas from the master ;-) Robot arm, six axis DOF (some background info) The robot arm that we are designing, is a so called six-axis DOF robot (DOF is an abbreviation for Degrees of Freedom). The six axis that it can move are shown on the following picture: This axis, located at the robot base, allows the robot to rotate from left to right. This axis allows the lower arm of the robot to extend forward and backward. The axis extends the robot's vertical reach. It allows the upper arm to raise and lower. Working in conjunction with the axis 5, this axis aids in the positioning of the end effector and manipulation of the part. Known as the wrist roll, it rotates the upper arm in a circular motion moving parts between horizontal to vertical orientations. This axis allows the wrist of the robot arm to tilt up and down. This axis is responsible for the pitch and yaw motion. The pitch, or bend, motion is up and down, much like opening and closing a box lid. Yaw moves left and right, like a door on hinges. This is the wrist of the robot arm. It is responsible for a twisting motion, allowing it to rotate freely in a circular motion, both to position end effectors and to manipulate parts. It is usually capable of more than a 360 degree rotation in either a clockwise or counterclockwise direction. The gripper to pick-up the parts, candy containers in our case. Since this is not a movement, it is not seen as a separate axis. So, let's start building! Building of the robot arm, work in progress (first prototype) We started with the upper arm of the robot arm. For the first prototype, we used a a copy of the crane grabber for the gripper part. Three motors were placed in the upper arm (for movement 5, 6 and 7). The result can be seen below: And all worked fine, apart from one major disadvantage: to make the movement "axis 4" possible, the upper arm needed to be connected using a turntable (art. 4624645). But the weight of the upper arm was too high for the turntable. It started to bent a bit, making the rotation (axis 4) almost impossible. So, we needed a new upper arm but much more light-weight. Building of the robot arm, work in progress (second prototype) We discussed in the team what could be improved. And if the weight of the arm is too much, it needed to go on a diet. So, we looked for a way to put the motors in the upper part of the arm and to get three axles through the turntable. That would save lots of weight: 1) because three motors are not needed in this part of the arm, and 2) because the arm could be much shorter. But is it possible to get three axles through one turntable? Yes, you can. I found a video that does the trick, you can find it here: Another solution uses non-Lego parts: Quite a nice solution but we have a restriction that we don't use non-Lego elements. If three axles is not really possible, let's step back to a two-axle solution. And so we did: we created an upper part of the robot arm with only one motor and a simple fix to get two axles through the turntable: The result of the second prototype can be seen here. We said goodbye to the grabber and made a two-finger gripper. And indeed, the second prototype was better than the first time. Take a look at a (kind of) complete upper arm: But another major disadvantage: if the arm made a movement around axis 5 or axis 6, the gripper opens or closes as well. The reason is that the gears that control the movement of the opening/closing of the gripper, are also rotating when the gripper is rotated (axis 6) or when the wrist rotates (axis 5). You can power the motor that controls the gripper to compensate, but it is not accurate enough. So... goodbye to prototype 2. Building of the robot arm, work in progress (third prototype) How can you prevent gears to turn when you don't want them to....? Remove the gears! So the next (and hopefully final) prototype uses pneumatics to control the gripper. We added two touch sensors to the upper arm to detect the position of movement 5. In the photo above, the read L shaped peaces are pressed against the touch sensor when it reaches the end position. At the other side, the same principle is used to detect the other end position. Next to build: a sensor to detect the rotation position of the gripper. And the motor(s) to control the movements 5 (wrist) and 6 (gripper rotation). If that is finished, the upper arm is ready and we can continue with the part that holds the upper arm. That's all for now, I'll keep you posted. Please let me know what you think of it. Enjoy, Hans
  11. In 2018, Sioux.NET on Track was not allowed to show the train layout at Lego World 2018. Fortunately, the Lego store Toypro in Nederweert (NL) offered us the space and opportunity to demo our layout at their place. December 28, 2018 we gave a successful demo to the visitors. You can find pictures at our Flickr page and a video on Youtube. Some facts and figures: The layout at Toypro used a space of approx. 7 x 3 meter. We use a total of 15 Lego Mindstorms EV3 bricks. The EV3 bricks are running (relatively) small programs written in the EV3 programming language. Each brick is only capable of handling the local functionality, e.g. the delta crane can load containers from the conveyor belt to one of the four wagons. It receives a command to do this from the master PC application. Some builds are controlled by two EV3 bricks in Daisy chain modus. We didn't use three bricks in daisy chain because of the buggy firmware :-(. The master PC application is written in Microsoft C# and WPF. It sends commands using the EV3 mailboxes to start a function and to receive status updates. For example, when the train arrives at the Delta crane, the train sends a message to the PC application that is has arrived at the loading area. Next, the PC application waits until the conveyor belt sends a message that a container has arrived at the loading platform. Then the PC application sends a "load wagon" message to the Delta crane. Etc. All the bricks are connected to the PC via USB. Two exceptions: 1) The train is connected using Wifi. 2) The EV3 that controls the air pump, works standalone. Enjoy, Hans
  12. I am planning to create new GBC modules in the coming years. It will be a combination of Lego Mindstorms and Lego Technic. So not mindblowing mechanical constructions like Akiyuki, but constructions that can only work because they are controlled by the intelligent Mindstorms brick. My first module that I am trying to build (still unsure if I can make it work), is based on the Planar Parallel Mechanism that I saw on Youtube: I find it really cool how it moves. And I thought: let's build this, and use the grabber (visible from time frame 1:23) to pick up balls at the left side of the GBC module and bring them to the right side. Here is an LDD sketch from the first prototype: And a small movie of the first test. The green markers are there, to put the prototype in the start position. That's my major issue right now: how do I now where the four legs of the mechanism are? Working on that now, will keep you posted. Suggestions and compliments are welcome ;-). Regards, Hans aka Mindstorms GBC
  13. I'm trying to use EV3 with Scratch. I've posted few videos. Maybe someone will be useful.
  14. I have a small IT class project for school where I have to program an EV3 robot through the small basic extension. I want the robot to play a sound file (a short rsf file) but I don't have access to all of the folders nor do I have access to the EV3 software... The sound file I want to play was made at home using the EV3 software but I can't use the exported rsf in my code for some reason. I have tried several things but without access to all the folders (I can reach several folders but not through the root so I can't reach the sounds folder) and the EV3 software I'm stuck... Can anyone help me with the rsf without saving it in the sounds folder?
  15. A new video has been uploaded to our Youtube channel. In 2019, lots of new elements have been added to our layout. To name a few: the warehouse, able to store 60 containers with candies, with two independent stacker cranes, the four candy circles, and an updated delivery station. Also brand new is the PC software that connects everything. We have worked hard to get the software working stable and with success. You can see the result in the video. Enjoy the video! -- Hans
  16. Hi. I'm new here but I've been lurking a bit and now I've decided to make a post. I've built a large biped, through multiple iterations in the last 7-8 years. It's a decent build but I've decided I'd like to rebuild it with linear actuators as opposed to all of the current gearing used. Just like I read another poster say in some other thread here, moving the black part of the turn table while keeping the grey part stationary will add a ton of friction. This unit works pretty good, I had it posted on the lego mindstorms site before it shutdown. I also posted it to bricklink as well. I still think it would benefit from LA's, I think there would be less friction and better overall efficiency as opposed to the current 6 turntables driven by one motor. Bricklink Destructor Page I'd like to post pictures and such here but apparently I'm limited to 102.4kb of upload on this post. Please take a look at my post at bricklink and give me some input. There is a .io to take a look at the model. I've also changed the zamor launcher I'm using since I built the digital model. I'm using a standard hailstorm configuration with standard magazines, I've found them to be much more reliable than the design I was using when I build the .io. I've considered building an "agitator" into the zamor mag to prevent ball jams, but the rebuild of the Destructor is priority. Current biped info: Walking: This is achieved by one motor mounted on the bottom center of the biped. It has an 8 tooth gear driving the turntable, which in turn drives another turn table above it and attached to it. The top turntable pulls the legs forward by about 4 studs. The turntable attached to it is responsible for driving the gear inside each leg, which changes the angle of the foot to take the weight while stepping forward. Obviously the legs are synchronized by the motor, as synchronization is very important for this model. Turning: This is achieved by driving a turn table with a worm gear attached to a NXT motor. The is a touch sensor located by a tab in the leg attached to a gear. This is synchronized with when the foot has the weight on it, allowing the sensor to indicate when the foot will be active. At the same time we also know the other foot can rotate back to its original state if it is still in a turned state. Weight: Probably around 1-1.5 kilo Speed: About 40 cm /minute Zamor launchers: Typical hailstorm style launchers. May come back to them once I can work out a way to use linear actuators for the walking portion of the biped. What I was thinking for this build: (Starting from feet up in terms of mechanical workings) First a rough motor idea, I'm using an EV3 to control the machine. Motor 1: Walking/Turning Motor 2: Gear switcher for walking/turning Motor 3: Zamor launchers Motor 4: Maybe instead of switching I could use this motor for turning?? Not sure yet.... Feet: This is where my current turning mechanism is. For a LA driven biped, I was thinking a possible gear switch mechanism to change from walking mode to turn feet mode for turning. Still deciding whether a LA or gear is the better for this. I'm kind of leaning towards gears due to the rotation forces needed for turning the foot. And the difficulty of getting rotational force through the leg down to the foot, while maintaining minimum torque/slop. Walking: I still think one motor driving both legs is best due to the absolute synchronization required. One thing I am considering Is sending two rotational forces through the leg, (if feasible) one to control walking and a gearbox to switch to feet rotation. The second rotation force will operate the gearbox for walking or turning the feet. Possibly I could use the second rotation to send through the leg, knee and down to the foot. Now that I think of it maybe CV joint could do this. Zamor launchers: Maybe they would even benefit from the LA treatment? To be looked into at a later date.... Appreciate any input anyone has. If the link doesn't work the biped is named Destructor. It's on the Bricklink Studio page. Thanks. Edit: For whatever reason the studio page takes forever to load. It eventually does though.
  17. Hi. I was working on my car MOC (with a four-speed gearbox designed by Sariel) and had some unfortunate events happen. As stated in the title, the differential is somehow making the gear ratio higher than I need it. The gear moving the diff is moving at the same speed as the power input, but the wheel hub moves one rotation for every 3/4 rotation that I move the input shaft. Is this differential piece supposed to do this? I want the wheels to move at the same speed as the motor at 4th gear, which brings me to my next problem. I hear rapid-fire clicking noises every time my car is in 3rd and 4th gear. This happened to my other MOCs too, but I was able to solve it. Since the car is to be powered by two EV3 large motors, I actually believe there might be a clutch mechanism in the motors such as in the Technic linear actuators that also make a terrible clicking sound when they move all the way up or down. Whatever it is, I'm open to responses and hope the Eurobricks community could provide an explanation and solution about both of these issues. Here's some pictures, the orange and red pieces in the first pic were for testing the rotations. ' Thank you for your time.
  18. This is a 1:8.3 scale Technic MOC car I am making powered by EV3. Things have been going well until I ran into some space issues with some Large Motors. I wanted them to be vertical, but they were too big, so I'm trying ways to get more space so the motors won't be very visible when I build the exterior. In the right picture, I positioned the motors at an angle to save space, however it may make the rear too long. The maximum room I have (according to blueprints) for the motors is 2.5 inches away from the rear wheels, so I need to save a lot of space or I have to expand the rear. All in all, I have to position the motors where they are not too high or not too far from the rear wheels. I'd thought I post this issue I have because I wonder if there is any other better way to do this. Thanks in advance for any thoughts or advice.
  19. Here's my little dumper truck. Functions: - drive & steering (obviously) with PF - adjustable suspension angle (left/right) controlled by a Mindstorms EV3 unit that reads sideways tilt from an accelerometer to keep the truck upright; basically a self-leveling suspension - dumping with EV3 reading PF remote using an IR sensor - Baja Claw TTC tires by RC4WD on Lego 56mm rims. I've tried to fit more, but the problem with these trucks is that the chassis has actually little room, it needs to be pretty flat to fit under the cargo hold, and the area with the most room (front of the front axle) is taken up by the Mindstorms EV3 unit. There was a 4-speed transmission initially, but I've taken it out as it kept disengaging under stress (the truck weighs 4.156 kg). Photos: https://www.flickr.com/photos/44849526@N06/albums/72157710566416217
  20. Hi, After lurking for several years and after arising of this new Mindstorms forum it's time to start sharing some of my own MOC's. I present the Boogie Burnout: This bot is based on the Rocker-Bogie suspension mechanism, which is also used for the Curiosity and Opportunity Mars rovers. The Bogie-Burnout is my own interpretation of the system and not a copy of existing robots. My main goal was to experiment a little and see if the Rocker-Bogie system would work in the scale of my other MOC's All 6 wheels are able to pivot up and down and turn in every direction. The main problem I faced building a rover this scale was the flexibility of the Rocker arms in conjunction with the middle base part of the robot. Adding flexible links between the left and right wheels solved most of the flex, but turning the wheels 90 degrees still caused the robot to look like a drunken sailor. Adding removable stabilizers solved most of the wonky movements. When not driven 90 degrees side wards these links can be released on one side to give back all flexibility to the rocker system when driving over obstacles. As it turned out, a Lego Technic structure this big has enough flexibility to drive over obstacles without having to unlink the stabilizer bars. The wheels are driven by 4 medium Power Functions , which are geared down in a ratio of 11.7 in two steps. To prevent the current regulator kick in, each medium motor has his own IR receiver, which makes 24 receivers in total. The Power Functions remote is driven by two Mindstorms motors, one for speed control and one pressing the stop button. Controlling two channels simultaneously and thus reducing the amount of IR receivers resulted in lag and speed difference between motors. For each two motors and receivers there is one battery box, this again to prevent the current limiter kicking in. The outside plating of the rover can be removed easily within seconds. Bonus: The Bogie Burnout is high enough to drive on top of one of my older MOC's, which opens some possibility's on events :) Video: Note for the purists: This is not a 100% pure MOC. Some 0.5mm Teflon rings are used to prevent slack in the mechanism and the Mindstorms cables are custom made to length. Some tape is added to the wheels to prevent them from scratching.
  21. This article about the new Candy Circles, is related to two other threads of mine: 1) The Lego Candy Sorter 2) The Lego Candy Warehouse The new developed Lego Mindstorms EV3 Candy Circles are replacing the Candy Sorter. The color detection of the Candy Sorter was simply not reliable enough. Once calibrated, it worked fine but it was too sensitive for a change in light. Therefore, it was not good enough to perform for a longer time, e.g. at Lego World or during another demo. We decided to go back to manually sorting the candies. But then we still needed some dispense mechanism to release a candy, that would be stored in the Candy Warehouse. I came up with the following solution: Four large circles, containing the candy. A circle would be able to release one candy at a time. The released candy would then be transported to the Trebuchet (where the candy would be put in a container, and then the container with candy is stored in the Candy Warehouse). This was the first prototype: As you can see, there is a touch sensor and one marker added onto the ring. The marker was used to sync a full rotation. After the sync, I would just rotate the ring 360/16 degrees to release the next candy. Because there is always a bit of drift, the sync (per full rotation) was planned to make sure that the drift could not increase infinitely. But, of course it would be better to stop exactly at each bucket. So I made a second proto. As you can see, each bucket has its own marker to stop exactly at the right position. This proto was good enough to start building four circles. And a matching conveyor belt. This is the result: And of course a video: Next step to make: how to determine that a candy circle is empty? I don't have free ports to add an additional sensor. And of course it needs to be reliable! Will keep you posted. -- Hans
  22. Hi all, I have a LEGO office building with an elevator. I've automated the elevator with a mindstorms touch sensor. The program starts by descending down the elevator shaft until it sits on top of the touch sensor at the bottom of the elevator shaft. Ideally, the touch sensor is supposed to trigger the mindstorms motor to turn in the opposite direction and pull the elevator back up for fifteen seconds. The mindstorms motor turns again in the opposite direction, so the elevator descends down again to hit the touch sensor. (The process repeats indefinitely) In a vacuum, this program works fine. However, I've had numerous issues with the sensor not triggering, and the elevator eventually winds in the wrong direction and binds with the roof, breaking. I've tried making the elevator heavier, but it still has issues. I want to program a fail safe so that it will bypass the first wait block or cut off the program if the touch sensor doesn't trigger within a certain timeframe. I've included a picture of my current program. Within the infinite loop, I want the loop to start by waiting for the touch sensor to be pressed, then executing the two other motor commands I have following it. While the program is waiting for the touch sensor to be pressed, I want another thread to wait for twenty seconds. If the touch sensor is not pressed within that timeframe, I want the program to bypass the first touch sensor wait block and continue with the last two motor rotations (then repeat). I've been able to branch off into two different coding threads within one program, but I can't recombine the two inputs into the beginning of one block. How do I do this or accomplish my goal in another way? I'm at a convention right now and I really just want this to work. Some more information, the mindstorms motor is connected to a control switch, which tells my power functions motor which way to turn. That's why the mindstorms motor rotations are so short. Thank you everyone for your help.
  23. MINDSTORMS EV3 OMNIDIRECTIONAL ROBOT INTRODUCTION The reason you are stuck with me as Moderator/Admin is actually caused by Mindstorms EV3. I proposed an Index for Mindstorms and Bonaparte figured I could make one myself. Resulting in me making one, and one thing lead to another. In 2013 TLG released a brand new edition of LEGO Mindstorms. Owning two NXT sets, which I had hardly used to build something cool, I was determined to change that when I bought the EV3 sets. I first bought the 45544 - EV3 Education Core Set set, and shortly after that I added the 31313 - Mindstorms EV3 (Retail) set to my collection. After some initial experiments both unit had been turned on approximately the same number of times as the NXT. This being a terrible waste of potential, I recently decided to start building the robot I have been planning in my mind for a long time. My goal is to build a fairly big humanoid(-ish) robot. Does that sound familiar? Of course it does, since my good mate Simon Burfield (Burf2000) has built a super cool humanoid robot recently. We also know him of the Wheelchair and Segway. And yes, he is a big inspiration to me. What I am aiming at is a Omnidirectional Robot with one or two arms and a Wall-e like head. The height of the robot will be approximately the size of a child, let's say around 120cm. Omnidirectional means allowing movement in all directions (more on that in the next chapter). Since I have no idea where this will end, I have created a WIP topic, in review style. I will add chapters along the way. When I add a new chapter I will post that new chapter and edit the original post. Feel free to comment, hint, tip, suggest, mock and ridicule Before we continue I'd like to give my man Burf and the guys at Rotacaster a big thank you! OMNIDIRECTIONAL WHEELS Here's the wikipedia description for Omni wheels: Omni wheels or poly wheels, similar to Mecanum wheels, are wheels with small discs around the circumference which are perpendicular to the turning direction. The effect is that the wheel can be driven with full force, but will also slide laterally with great ease. These wheels are often employed in holonomic drive systems. A platform employing three omni wheels in a triangular configuration is generally called Kiwi Drive. The Killough platform is similar; so named after Stephen Killough's work with omnidirectional platforms at Oak Ridge National Laboratory. Killough's 1994 design used pairs of wheels mounted in cages at right angles to each other and thereby achieved holonomic movement without using true omni wheels.[1] They are often used in small autonomous robots in intelligent robots research in the academia. In projects such as VEX Robotics, Robocup and FIRST Robotics, many robots use these wheels to have the ability to move in all directions. Omni wheels are also sometimes employed as powered casters for differential drive robots to make turning faster. However, this design is not commonly used as it leads to fishtailing. LINKS Some interesting links: Omniwheels Mecanum wheels Ball transfer unit Holonomic Festo After 15 seconds you can see the Kiwi Drive in action: Control using gamepad ROTACASTER Here's the complete lineup for Rotacaster wheels with LEGO hubs. From left to right: 125mm 48mm 35mm As you can imagine the 125mm version are for heavy duty applications. Since the robot will probably by quite heavy, I figured the bigger the better. There's also a 125mm version with 3 wheels instead of 2. However, this will probably suffice for my robot. The diameter of the 125mm is slightly larger than a 15L liftarm and the width is slightly less than 6L. CONCEPT Here's a simple concept sketch. And an artist impression of how the robot should look like. The end result will probably look nothing like this one, but it's nice to have an idea. PROTOTYPE I have started building the prototype. The idea was to buil in a modular fashion, but this early concept failed miserably. VERSION 2 The triangular shape poses quite a few challenges. Not that I hate a challenge, but I am contemplating on making a four wheeled version. The idea is to create 4 standalone wheel units, which can be attached to a center hub, possibly with shock absorbers. The red liftarms underneath need to be removed, because they will prevent the wheels to be mounted. This is just a simple LDD setup I drew, since we discussed Bob's problem with turntables. That made me rethink my setup. Some turntables and dog bones for the new setup. When using the modular setup for the wheels, I could easily switch between different setups, three or four wheels. My progress is what you see in the pictures. Now let's have fun discussing and mocking. Alasdair mocking in ...3....2....
  24. One of the policies within Sioux.NET on Track, is to change a build every three years. In other words, when a build has been part of a Lego World demo for three years, it should be replaced by a new one. For example, loading the train was first done by the container crane, now it is done by the delta crane. The same applies for the train: the first years, we controlled the train by an NXT, now it is controlled by an EV3. For the new layout, I am thinking of replacing the train by a monorail (and thus renaming the group to "Sioux.NET on Monotrack" ;-). I always use Youtube as inspiration. To see how others solved the typical problems you run into when building something. But I haven't seen a Lego Mindstorms monorail yet. The Lego Technic monorail created by "Osi" (click here for an example) is most nearby for what I have in mind, but it is not using Mindstorms inside. In other words, I will have to use my own imagination. What a pity ;-) I started with creating the track. This was my first attempt: Although it looks good (I was aiming at an open, industrial look), the curve is not smooth enough for a train: So, I made a second attempt: That looks much better. It was not easy to get the curve smooth AND find a brick with the right distance. This is how I managed to get this curve: A simple train (only proof of concept until now), runs easy through the curve: The next days I will continue building a motorized train (proto). Let me know what you think so far Merry Christmas! Regards, Hans
  25. So this is tragic news... the Mindstorms Gallery is closing? Does that mean that I lose all my projects that I uploaded? As if closing the message boards wasn't enough? Fortunately, I have a website, so all of that can be moved... but I still can't believe this is happening. So many memories... And I really dislike the format of the new gallery. It appears as if you can only add pictures, similar to the Technic gallery. That's a huge step backward. What is LEGO doing?