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Hi, I want to ask the users of EV3 system: How much can you rely on position determination made by EV3 unit that computes it from the quadrature encoder inside the EV3 servomotors? Particularly in a situation where the position of a driven mechanical system (e.g. a robot arm) changes quickly and in both directions? Is it precise and robust enough so that limit switches may be omitted? I saw some robots with EV3 and many were without these switches. I ask because I am experimenting with EV3 motors combined with Arduino and even though my control programs (inspired by this project) seem to be fast and accurate enough, there are always small deviations of the position after several movement repetitions. After tens and hundreds of repetitions the deviations becomes critical. -
Lego GBC and Mindstorms EV3
Hanso posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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 -
EV3 with Scratch
dawidmarasek posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I'm trying to use EV3 with Scratch. I've posted few videos. Maybe someone will be useful. -
Self-Driving Minirobot
Tomas TECHNIC posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This simple robot with a sophisticated program can detect obstacles and avoid collisions. Building instructions and program are available on Rebrickable. https://rebrickable.com/mocs/MOC-36666/TomasTECHNIC/self-driving-minirobot/#comments -
i had some wadering done on www en fond www.makecode.org this is a site whit several mirco controlers controled by a kind of scratch you can also program in javasrcipt i made the folowing js code [ not tested jet ] let move = "wait"; sensors.remoteButtonTopLeft.onEvent(ButtonEvent.Pressed, function () { move = "turn left" }) sensors.remoteButtonTopRight.onEvent(ButtonEvent.Pressed, function () { move = "forwart" }) sensors.remoteButtonBottomLeft.onEvent(ButtonEvent.Pressed, function () { move = "turn right" }) sensors.remoteButtonBottomRight.onEvent(ButtonEvent.Pressed, function () { move = "backwart" }) motors.stopAll() forever(function () { switch (move) { case "turn left": motors.largeBC.tank(-50, 50) break case "forwart": motors.largeBC.tank(50, 50) break case "turn right": motors.largeBC.tank(50, -50) break case "backwart": motors.largeBC.tank(-50, -50) break default: motors.stopAll() break } control.waitMicros(100) move = "wait" })
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Is there a way to not display certain programs and especially MyBlocks on the EV3 Brick Menu under a Project? The Kids have a project called CityShaper and it has 2 programs and about 10 MyBlocks. They only need to see the 2 programs and not all the MyBlocks listed so it is easier to select during the FLL Competition.
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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
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Space Issues With EV3 Large Motor
StudWorks posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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. -
Alexa LEGO Voice Challenge contest
Coder Shah posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
https://www.hackster.io/contests/alexa-lego-voice-challenge Pretty great. -
Ev3 daisychaining sensors not working
botechat posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I'm daysichaining two ev3 bricks, and putting a color sensor on the slave brick, on reflexivity mode. The sensor is connected to port 1 on the slave. The sensor appears as connected, and mostly works, but sometimes it just returns the maximum value (128) for a while, and then returns to reading. How can I fix this? P.S.- the sensor returns 128 even when it shouldn't, e.g. I put it on black and it returns 128. -
Continuous Power for Mindstorm
dr_spock posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I wanted to power static Mindstorm builds at shows/events through wall power instead of rechargable AA batteries. I was going to design my own AA battery adapters then I found these on Thingiverse. They came in STL files that can be 3D printed. You only need to print two per Mindstorm unit. They have a nice opening to feed the wires through. AA Battery Eliminator by movotrab: https://www.thingiverse.com/thing:3160060 I had to make a small notch on the battery cover for the wires to come out. From here you connect to a 9V DC wall adapter. -
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.
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Lego Mindstorms EV3 Candy Circles
Hanso posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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 -
Moon Lander Simulator
Coder Shah posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Built to commemorate the Apollo 11 mission, 50 years ago today. -
LEGO Mindstorms Elevator Programming
pjf1000 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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. -
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.... -
Lego Mindstorms EV3 Monorail
Hanso posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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 -
Microsoft's MakeCode for the EV3
BlueBillCanada posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Hello, I searched the site for MakeCode but came up empty. Has anyone used Microsoft's MakeCode with an EV3? It's an online programming editor similar to Scratch plus Javascript. The highlight for me is EV3 emulation including EV3 peripherals. This appears to be what brick firmware version 1.10E added. Anyone else tried this? Comments? -
I get that this isn't the topic forum to ask this under but, I need help with this idea. so I did research and look for how to use a webcam with ev3 and ev3dev_Python, but couldn't seem to find the camera model I'm using. My camera is literally called usb2.0 pc camera if that helps and have no clue about anything else. it works just fine to the only issue is how do I use any kind of USB camera with EV#Dev_Python?
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Al-Jazari's Elephant Clock
Coder Shah posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
My model of Al-Jazari's Elephant Clock. Hope you like it. Wikipedia article on the original clock. https://en.wikipedia.org/wiki/Elephant_clock Featured on the 1001Inventions website. http://www.1001inventions.com/elephant-clock-lego Pics 01threequarterfront by Ahmad Sahar, on Flickr 06sideview by Ahmad Sahar, on Flickr 07threequarterrear by Ahmad Sahar, on Flickr Video and Building instructions -
[EV3] Fully Automated Candy Warehouse
Hanso posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
As part of our fully automated train layout (see more at our blog here: siouxnetontrack.wordpress.com), I have started to build a fully automated container warehouse. The warehouse should be able to store a large number of candy containers. I want to build four rows with shelves to store the containers, served by two robots that can store and retrieve the containers. The first thing I needed is to build the vertical lift for the stacker crane. I looked at other builds and found out that there are three possible mechanisms to create the vertical movement: Gears climbing a toothed bar (element 3743), a nice example can be found here: https://www.youtube.com/watch?v=GToA2tOVyHg Cables pulling the lift up, an example can be found here: https://www.youtube.com/watch?v=rCNwQVjXz60 Chain links, an example that uses the small elements 3711 can be found here: https://www.youtube.com/watch?v=fQIAAb8x8MI And as you may have guessed, I have tried something different. I use the worm gears (element 4716) to get the vertical movement, this is the first test setup: If you stack the elements 4716 on top of each other, they should be aligned correctly to create one, long worm gear. I just finished a first prototype of the stacker crane. The crane has two forks, in order to store or retrieve a container from either the left row or the right row. The lift can move up and down, the (horizontal) movement along the row needs to be build. One EV3 M motor is used to move the forks either to the left or to the right. It uses a color sensor to determine the middle position. One EV3 L motor is used for the vertical movement. A touch sensor is used to detect the bottom position. Watch the video to see a demo: More details will be added later. Enjoy watching and please let me know what you think. Hans -
Hi all, A while ago I purchased the EV3Lights Led Controller by Mindsensors. The contoller is powered by a 12V adapter and it plugs into one of the sensor ports of the Mindstorms EV3 brick. To control the strip you need to download an EV3 Block and you are good to go. They even have sample program, which worked instantly! Christmas will never be the same!
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EV3-PD Protocol Droid
MajorAlvega posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This was one of those crazy ideas we have when are discussing with other LUG fellows. This guy from PLUG defied me to show a LEGO robot that translates conversation, much like the C3PO protocol droid from Star Wars. As usual, he wasn't really expecting ti could be possible with LEGO. I only had a couple of hours so I decided to copy a Raspsberry Pi approach of using “the Cloud”. Google offers a one year free trial so I registered and tried a few examples on my Ubuntu laptop, amazing what one can do with just a few curl commands! I wrote a sort of short tutorial. It is now obsolete but helps showing the way for further attempts. I used an USB microphone because I assumed there was no LEGO microphones. But there is - the LEGOCam (MINDSTORMS RCX Vision) has an embedded mic, sound quality isn't great but might (big might) be used - that would make a 100% LEGO hardware solution. By that time I had problems with initial authentication times - it took almost a minute before I can start using the Google services and it needed to be renewed after an hour. EV3 CPU is slow but probably not the only reason here so one of these days I might try it again. Of course, using a Raspberry Pi and a BrickPi would give much better results. -
The company I work for (Sioux) is one of the main sponsors of Tech United, the leading World Champion in robot soccer. So for me, it was obvious that we are going to release a Lego Mindstorms version of their robot. It will be available on the market as an extension set to the Home Edition version (art. 31313). The expected release date is december 2018 and it will be exclusively available at the Toypro (web)shop. The price of the extension set will be approx. 100 euro. Please note that you need the Home Edition to build this model. The soccer robot looks like this in real: And this is the version I made: This version is controlled by the infrared sensor plus the corresponding remote control. I'm working on a version with the Pixycam, that will be able to go to the ball autonomously. The omni wheels are the only parts that are not Lego. Please let me know what you think of it. Regards, Hans
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[EV3] Mindsensors Multiplexer
oracid posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Do you know this, http://www.mindsensors.com/ev3-and-nxt/21-multiplexer-for-nxtev3-motors You may have 12 Lego servos with only one EV3.
