Archive for November, 2013

9748OT_instant_new

On my return trip from Denver, I enjoyed another book.  Instant LEGO MINDSTORMS EV3 by Gary Garber is a quick read to get you up and going with the latest LEGO MINDSTORMS set. As you have seen in some of my previous posts, I do a lot with EV3 and I love sharing good resources for building robots.

Instant LEGO MINDSTORMS EV3 is a great introduction to the educational version of the EV3. The book is great for teachers who are looking to integrate robotics into their classroom. Topics range from building a simple robot, to creating a proportional line follower.

Garber refers to the various segments of the book as ‘recipes’ and that really is a good name for them. Each section breaks down into steps, along with CAD renderings or screenshots. This makes for a good tutorial as it is easy to follow. Be it good or bad, you don’t need to read most of the book. The images are that good and easy to follow.

ball

I would recommend this book for anyone, but with the focus on the educational kit, it is really best suited for teachers (or students who have access to an educational kit at school). Unlike the LEGO MINDSTORMS NXT, EV3’s educational kit is quite different from the retail kit. The educational kit contains different sensors (ultrasonic instead of IR, no IR remote, and a gyro sensor), software (the educational software directly supports these sensor differences and includes data logging), and finally different parts (most notably the caster ball, pictured right).

One interesting surprise with this book is that I actually know one of the technical reviews. Chris Rogers, a professor at Tufts University and director of the Center for Engineering Education Outreach (CEEO). Chris and I had worked on some NXT projects (mainly involving my RS485 work). We seem to keep crossing paths.

Naturally, with technical reviews like Chris, and the detailed recipes, Instant LEGO MINDSTORMS EV3 is a good book. While it does not go into to all the various ideas or projects that most other MINDSTORMS references include, it does a fine job of getting you up and going quickly. If you are looking for a quick read (under 100 pages!) or are like me and feel the need to read everything related to LEGO MINDSTORMS, you can find this book of amazon.com or from the publisher.

Advertisements

Blog Gets a New Look!

Posted: November 25, 2013 in News
Tags:

The old blue blog theme was cool and all, but recently I have been posting more photos and videos. I wanted to update my theme to better accommodate all the media. This new theme allows for larger embedded videos and images. Give me your feedback! I like it so far, but if you have a better idea, share it!

1386EN

As some of my readers know, I am in Denver at SuperComputing ’13. It has been a crazy week, but traveling also affords me some time to sit back and read. On the flight over I finished reading Getting Started with Simulink by Luca Zamboni. Overall this is a very good introductory book into Simulink, but it does require some mathematical background to truly understand what the author is doing.

Like LabVIEW, Simulink is a graphical dataflow environment and requires very little text code. For many, this approach to programming can be quite easy and improve productivity; however you need to understand how datalfow works. The author begins with a simple cruise control model that leverages a PI controller (more on that later). Like many systems that interact with the physical world, it maps well to dataflow. The author does an excellent job of stepping you through construction and testing of the  model. He even mentions some good shortcuts (like how to reset the zoom, a shortcut that I learned while reading this book).

Like any good tutorial, the Getting Started with Simulink builds on previous examples. Once you complete the first example, you build a model for a car. This exposes the user to simulation, one of the key advantages of Simulink. The book builds quickly and at first it seems like Zamboni is throwing everything but the kitchen sink at you. He really does challenge you, but Zamboni is there to step you through each step of building the model. From creating subsystems for for motors to simulating drag. The model is a very complete representation of a sports car and by the end you feel very accomplished. Best of all, you have actually mastered most of the skills required for Simulink. I would say this book covered 90% or more of the blocks that I commonly use. Another key aspect of the book is that it uses an up-to-date version of MATLAB and Simulink (2013a). While the basic concepts don’t change with time, features are sometimes tweaked or new file types supported. Zamboni does a great job of pointing out many of these minor differences. He really is an expert in the software.

Now about math and that PI controller. Well to be honest, the PI controller was just the first math-heavy aspect of the book. The model for the car does get kind of math heavy, but that is very much the nature if many models. While you don’t actually need to understand the math to follow along and complete the models, but it certainly helps. If you’re an engineer or engineering student, then chances are you know physics and calculus. For my non-engineering readers, don’t feel like this is a deal breaker. The author does explain what is going on, but probably not in the detail that you would like.

One other thing to keep in mind is that this book requires no hardware (no MINDSTORMS, no camera, no motors, nothing). So if you plan on interacting beyond simulation (given simulation is one of the big features of Simulink), you will have a bit more learning to do on your own. Personally, I think you should start in simulation, and once you master that, move to hardware.

Overall I would recommend this book to any reader. I know there are quite a few people out there that are just getting started with MATLAB and Simulink for LEGO MINDSTORMS. This is a great first step in mastering the environment. The book is available on amazon or directly from the publisher. The book also is available in ebook form for your tablet or Kindle.

1386EN I have been working a lot with MATLAB and Simulink lately. For both my academic work and fun. If you recall the MATLAB demo I took to the Orlando Mini Maker Faire, you know that Simulink is an important part of that project. Simulink works really well for LEGO MINDSTORMS as its dataflow paradigm maps nicely to robotic interactions. I have actually been working on a tutorial to get people started with LMS and Simulink (hopefully will be posted in December or January).

So why the picture of the book? Well I love having a good reference for my work and I am currently reading this book. I will be writing a review for Getting Started With Simulink by Luca Zamboni next week, but  so far it has been a really good resource. It might be worth checking out if you will be working with Simulink. The book assumes you have never used Simulink and gets you up and running, very quickly. Check back for the full review next week!

WP_20131111_0012013 welcomed a new attraction to the Walt Disney World Resort. No it is not a ride, but a new way to enjoy some of the Disney Parks. “Glow with the Show,” as its called, brings light up LED mouse ears. The ears can light up depending on the area of the park or show. I was last down in the Magic Kingdom on Friday and picked up a set. I have been wondering what makes these guys tick ever since I first heard about them from Disneyland.

WP_20131111_004First off, these are not the traditional beanie caps you can buy in the park. They fit more like a helmet with quite a bit of padding to hide the battery box. As you can see above removing the padding reveals the battery box and plastic support for the ears. The ears are attached via 1 screw and 1 rivet. This made them super hard to remove, and in the end, I never actually got it off.

WP_20131111_007Popping the plastic facing off the ears revealed a large tricolor LED (no surprise) and another smaller LED. My friend Matt did some searching online and discovered it was a 940 nm LED. This is probably used for inter-ear communication between different headsets.

WP_20131111_009The other ear (above) revealed another tricolor LED, but also an IR Receiver. Both ears contain a flexible PCB and go into the central part of the beanie cap.

WP_20131111_013Inside, the two flexible PCBs are attached to a central main rigid PCB. This is vary different from earlier models. The board has only a few test pads and is marked version 1.5. As you can see, getting to the PCB was hard due to the support plastic in the way. I had to cut the beanie open to get to it and then pop off a plastic cover. The PCB is held in place by a couple of plastic rivets that I was able to easily remove.

WP_20131111_016With the PCB out, it is also clear to see this revision uses a mechanical switch. The original Disneyland version had a capacitive button on the ears. (Probably for cost savings and simplicity.) You can see the switch connected to the red and white wires. This also means a physical disconnect between the PCB and battery. The switch is held in by a couple of screws and came out easily.

WP_20131111_019The photo above shows the electronics, cut free from their housing and battery box. The overall length is about 6 inches. A forward direction is marked on all the PCBs, indicating that direction does matter (even if the user doesn’t wear it correctly). The MCU is a TI MSP430. TI knows a thing or two when it comes to low power and that makes sense with this device that should a full day in the parks. (The ears blink randomly if there is no signal received.)

WP_20131111_020All said and done, this teardown took a bit more effort than I expected. There was a ton of foam to remove and in the end, I still had to cut the top off the hat. As you can see above, just a few tools were used. Special thanks to my friend Matt for looking up all the parts. Now time to see what I can do with! Lucky for me, the control codes have been cracked and it should be just as simple as implementing an IR transmitter.