Even though we are done with school for the year, I am trying to make sure that we are still learning over the summer. For the past three days we have been working on the LEGO Mindstorms: MindCub3r robot. We have an EV3 Lego Mindstorms kit, so we used the build instructions located at the MindCub3r website by David Gilday. All the programming for the robot is also located at the same website.

Corran and Matthias started the build Monday night. Lego Mindstorms robots typically take Matthias (our master robot builder 🙂 about 3 to 4 hours build. He builds the robot and then Corran will program it. It was later in the evening when they started the build, so they had to finish the build Tuesday morning. I ended up having to help at the end with the build, because the two LEGO Mindstorms: MindCub3r robot arms weren’t working properly. We finished our build around 11 AM on Tuesday. I was supposed to make scones yesterday that I was going to post about on the blog here, but since I was helping with the robot instead, well, the scones didn’t get made until today.

First stage of the build. Thias used an iPad to download the instructions. Here they were seeing if the Rubik’s cube would fit in the tray.
With the tilt arm and the scanning arm attached. We had a few problems with the arms. I’ll get to those.

I was wondering why Thias was bent down messing with the LEGO Mindstorms: MindCub3r robot like this until I had to help with fixing it! It’s the only way to actually see what you’re doing sometimes!

We had trouble with the scanning arm not being able to reach all the way to the Rubik’s cube. I checked the arm against the instructions and moved pieces that were in the wrong place. It was often things like a peg being in the wrong hole. Corran ended up getting the scanning arm to work like it was supposed to, by moving two sides of the arm one peg over.

The tilt arm wasn’t working properly because two of these little pegs were missing!
A fully functional robot!
The robot parts labeled

Corran took care of downloading the programming for the LEGO Mindstorms: MindCub3r robot. He ended up having to update the software and the firmware on the EV3 brick. Troubleshooting the programming took us about an hour or two. Then, when we got the programming working, the robot wouldn’t go past the scanning portion of the program.

We spent probably another 2 hours trying to figure out why we were getting a scan error. Finally, after it successfully moved past the scanning portion once, we called it quits for the day and decided to try again later.

This morning, I decided to look up reasons why we were getting the scan error and how to fix it. On a YouTube channel in the comments, I read that someone had fixed their error by placing pieces of cardboard in the tray to keep the cube from moving around too much during scanning. The cube has to be aligned underneath the sensor a certain way and since ours was bouncing around a lot in the tray, the sensor couldn’t read the colors properly.

After some jury-rigging of the tray with slim pieces of cardboard and some mishaps with scotch tape, we got the robot working!

This is one of the best videos I could get of the robot solving the Rubik’s cube. It was a hard 3 days’ work to get it to this point! My two oldest boys kept wanting to quit working on it, but I wouldn’t let them. I told them that this is how real life is. Most of the time, a project you are working on won’t always work or go the way you want to the first time. You work on it one piece at a time until the project is finished.

As a bonus, Matthias and I learned how to solve a Rubik’s cube ourselves! We had to go to a website to figure out how, but at least, now we can do it!

I found this website very helpful in the way the steps were presented – Rubik’s Cube solution.

This was our first real project with the LEGO Mindstorms EV3. We are hoping to work on more over the summer!


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This Post Has 17 Comments

  1. Anonymous

    Edison said that he didn’t fail 10,000 times, that he found out 10,000 ways that it wouldn’t work.

  2. Isabelle

    That’s awesome! I was skeptical at first that it would solve the cube, but it did. And fast too! Wow! I’ve been very interested in purchasing a Lego Mindstorm set for our family. There are so many things you can do with it. It’s just so darn expensive. We’re putting money aside and hope to get one in the next year or so. Keep posting your Mindstorm creations. I want to see more!!! 🙂

    1. Lynn-Marie

      It doesn’t always work correctly, but it’s neat when it does! As with any experiment, things go wrong: the tilt arm doesn’t flip the cube, the RGB sensor mixes up red and orange, there is a scan error, but you just keep trying until it works! I am hoping to do at least one Mindstorms project a week over the summer, if possible. It was worth it to buy, but it does take a bit of time to work on, which makes it great for the summer!

      1. Isabelle

        Good to know. I’ll make sure we have lots of patience when we get started. Looking forward to seeing more of your projects.

        1. Lynn-Marie

          I wanted to get the education version of Lego Mindstorms but I was able to get too good of a deal at Legoland for the EV3 home version. I hope you guys can get one soon! It’d be fun to collaborate on projects for it ?

          1. Isabelle

            That would be pretty cool.

  3. David B.

    Where did you place the cardboard in the turntable to fix the “scan error” message?

    1. Lynn-Marie

      The cardboard pieces went right alongside the “walls” of the turntable. We had issues with the Rubik’s cube moving too much in the turntable so making the walls thicker helped to keep it in place.

    2. Lynn-Marie

      There is one more help that I forgot to mention in my post: making sure there is enough light; our MindCuber had problems scanning if it thought it was too dark

  4. Anonymous


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