Make: Lego and Arduino Projects Make amazing robots and gadgets with two of today’s hottest DIY technologies. With this easy-to-follow guide, you’ll learn how to build devices with Lego Mindstorms NXT 2.0, the Arduino prototyping platform, and some add-on components to bridge the two. Mindstorms alone lets you create incredible gadgets. Bring in Arduino for some jaw-dropping functionality—and open a whole new world of possibilities. A Note Regarding Supplemental Files Assumptions This Book Makes Contents of This Book Conventions Used in This Book How to Contact Us Build the Lego Model Attach the Arduino and Bricktronics Shield Setting Up the Programming Environment Don’t Forget Your Libraries! 2. Anatomy of Lego Robotics Technic Beams, Mechanics & Connectors Expanding on the Mindstorms Set History of the Arduino Project Anatomy of the Uno 5. Project: Chocolate Milk Maker Build the Pump Assembly
Wiring the Aquarium Pump Attach the Syrup Bottle Build the Mixing Attachment Wire up and Install the Electronics Adapting the Power Functions Wire 6. Basic Electronic Theory Basic Concepts in Electricity Voltage, Current & Resistance Series & Parallel Connections Know Your Electronic Components Determining a Resistor’s Rating Passive Infrared Motion Sensor Temperature and Humidity Sensor Assembling the Gripperbot’s Electronics Download and Install the App Wiring Up Bricktronics Equivalents Mounting PCBs to Legos Adding Molex Connectors to Lego Wires Driving a DC brushed motor Battery Dos and Don’ts NXT to Arduino CommunicationI know I need a new Lego robot. Actually, I need two. I have the Lego Education edition, and I’ve got a retail set on order from a local toy store. I was sold the moment I saw them at CES this year. I also had the chance to borrow (and return) a retail set from Lego in advance of their launch on September 1, and I’ve been putting it to the test to see how it performs.
The EV3 is the first update to the Lego Mindstorms robotics set in three years, and it officially goes on sale for a steep $349 on September 1. Is it worth it? Do you have kids with an interest in robotics? Are you willing to spend this much on a toy? This is a toy that teaches kids (age 10+) programming and engineering skills. It allows exploration of robotics concepts without needing to understand electrical engineering or advanced programming, but it isn’t dumbed down to the point that it becomes boring for older kids or even adults. In fact, the GeekMoms and GeekDads can’t resist a good Lego robot building challenge. So what does the EV3 bring to the table? It still consists of the Lego Technic pin and beam construction system, which allows you to build strong robots with moving parts better than the standard Lego System. The CPU brain of the Lego Mindstorms is still the Brick. I’ve got a comparison shot between my NXT 2.0 brick and the new EV3 brick, so you can see how the system is still basically the same black and white display on a large, sturdy brick:
Underneath that similar brick, there’s a newly updated, faster processor. There’s also more expansion with an SD card slot on the side, and you can program directly on the bot. The NXT 2.0 allowed you to string together a few commands, but if you wanted to do anything fancy, it always had to be done on a computer and transferred to the bot. There’s a caveat here. Full on-the-bot programming is cumbersome. It involves a tiny screen and a lot of hitting up and down buttons. However, the fact that you can do this at all is great news. It means you can have a team or a group of kids that have no access to a computer, and they can still program their robots. I’m immediately thinking of classes, club meetings, camps, and other settings where team robot building challenges would just be amazing. The other price we seem to have paid for the revamped brick interface is in start up and shut down time. My NXT 2.0 brick starts and shuts off pretty much instantly. The EV3 takes 30-45 seconds for each.
That’s not a big deal in the scheme of things, but it may be a long wait for kids with short attention spans. The new EV3 has some of the same sensors and servos as the old NXT, and many have improvements. The large motor servos are the same, but there’s also a small motor servo. The color sensor is easier to attach to your bot. There’s now only one touch sensor, and there’s a brand new infrared sensor with a remote “beacon.” This replaces the ultrasonic sensor in the retail sets. (The Lego Education set includes the ultrasonic sensor but not the IR sensor and beacon.) The EV3 seems more playful and just a little cooler than the NXT design. Everything matches the new red and black color scheme, instead of the Google-esque multicolor mismatch of the previous version. The IR sensor has eyes painted onto it rather than the implied eyes of the ultrasonic sensor. The mostly decorative “wing” pieces have stickers to make your robot appear more like a battle-worn survivor of a space war.
The old NXT included a paper test track that got torn up pretty quickly after you put it on the floor. The new EV3 has a test track that comes as part of the box itself. Cut off the outer layer of the box, and it becomes the test track. It’s both sturdier and more interesting than the previous version. One area that seems like Lego was trying a little too hard is in the naming conventions. The EV3 has an E to 3 substitution in all the demo model names, so the Track3r, the Spik3r, the R3ptar, etc. That feels a little too Leet, and it won’t age well. The good news is that once you build them, you can call your models whatever you want. Speaking of models, there are tons of models and instructions right out of the gate. The box instructions only include the bot pictured at the top of the page. Well, it’s actually three bots in one. You start with a simple tank, add the small motor servo for a spinning “blade of death,” and then add the IR sensor for a remote control tank.
The “Track3r” bot comes with a demo program that moves it a few times, makes some noises, and adds some on-screen eyes. The whole thing takes less than an hour to build, and it means you can make something that just works right away. You also get instructions on how to download several other models, and you can preview the instructions on your computer screen. If you have an iPad, you can also take advantage of an app that shows you how to build the optional models. The iPad app, designed with the help of Autodesk, is just a brilliant idea. It offers animated, 3D, step-by-step instructions, so you no longer end up realizing five steps from the end that you missed a peg or axle at some point. Once you’ve mastered the basic steps, you can use the concepts you learned while building the models and make your own robots. The iPad software would be even better if it also supported iPad-based EV3 programming, but no dice. The software for the EV3 doesn’t ship on disc like it did with the NXT 2.0.
Instead, it’s a free download. I have a friend who lost her NXT 2.0 software only to discover that she couldn’t just download it somewhere. I’ve even heard that the new software is compatible with the old NXT 2.0 bricks, other than not supporting some features that are exclusive to the EV3. The new EV3 software has an updated look and feel but still offers the same drag-and-drop visual programming. If you think that’s too much of a baby step, the operating system behind the Ev3 is Linux, and I’ve been told by Lego reps that they’ve made it easy to bypass the visual programming tools and just hack your robot directly. You can also hook up to four EV3 bricks together for some sort of super robot. You might ask yourself why you’d want to spend nearly $350 on a Lego robotics kit instead of buying a Raspberry Pi for $45 and learning some Python or buying an Arduino kit for under $200 and learning more about electrical engineering. It’s a legitimate question. Some people are going to want to just go for the cheaper options.
Some people will want all of them. They do different things, so it’s not an all or nothing deal.The Ev3 costs a lot upfront, but it’s tough and reconfigurable, and used Lego Mindstorms kits have traditionally held onto their value pretty well on eBay. Other robotics platforms are either used up in the process of building them or go through processor innovations so fast that nobody is interested in the old models. It’s also a great entry point, especially for parents who aren’t robotics super whizzes themselves. You really can step in and assist your younger child or allow your older, enthusiastic child to go hog wild on their own. You can always work your way towards more complicated systems later on. Lego did a fantastic job updating the EV3 with new sensors and better peg slots for building with the old sensors. The expandable brick and new interface are fantastic once you learn how to get around on them. Sticking with the traditional black and white screen display means longer battery life and a more durable device, although eInk display would have been a great innovation here.
I would have liked to see iPad and Android tablet versions of the programming interface to make the robot truly computer independent, but there’s still room for Lego to go in that direction in the future. If you’re already a fan of Mindstorms, you’ll want to get this new model. If you are new to Lego robotics, I suggest looking for a First Lego Robotics League or similar group to explore the possibilities and make sure your child is enthusiastic enough with the idea. As with anything you program, you have to have some tenacity to problem solve. That’s the sort of skill you may want to cultivate in your children. Children under the suggested age of 10 will need a lot of guidance (there are small pieces, the pegs are hard to push into the bots, and Mindstorms can take some abuse—but not kids who want to step on them or throw them from great heights). My 11-year-old had no difficulty with assembly, and once she figured out how to transfer programs, she was debugging and problem-solving bot actions in no time.