Arduino - Adventure #3

Is nothing ever easy? Adventure #3 involves rotating a servo motor back and forth 180°. Since all of my servo motors have a 3-hole female connector on the end, I didn't have bare wires available to connect it directly to my Arduino UNO. So instead of cutting the connector off the end of my motor, I decided to use one of the shields I've accumulated from different vendors. A shield is a board that can be plugged on top of the Arduino printed circuit board (PCB) extending its capability. Actually, I don't know that shields "extend" the capability as much as just make it easier to do something. In this case, I decided to use Pitsco's new shield, because it has 6 male connectors for servo motors, plus an additional connector for a battery pack, mounted right on top - no messing around with breadboards this time. All I had to do was plug in my motor and battery pack and I was ready to go. Right??...wrong!

Unfortunately, I discovered that the Pitsco shield was a bit bigger than my Arduino UNO - there were 4 extra pins sticking down with no holes available to fit them in. I had been told that this shield was totally compatible with the UNO, but it definitely wasn't.  Luckily, I had SparkFun's Arduino Redboard - an UNO look-alike, which fit the Pitsco shield perfectly. Upon doing some Google research, I discovered that I have an UNO original, which indeed is 4 pins shorter (2 each side) than the current Arduino UNO and SparkFun Redboard. The new UNO uses a different microchip which allows for faster transfer rates and more memory (always a nice improvement). The pin layout is identical between the two models, so I can still use my UNO when I'm breadboarding projects, but if I want to use a shield, I'll need to stick with the Redboard.

AppInventor

I've always wanted to write an app, so I decided to check out AppInventor. AppInventor is a cloud-based app-development tool that was originally provided by Google, but is now maintained by MIT. The good news is, it's free; the bad news is that it's limited to Android operating systems - not a problem for me with my Samsung phone, but limiting in that half the population own Apple products.

AppInventor uses drag-and-drop blocks of code, so it is fairly easy to put together a working app very quickly. There are a multitude of tutorials on the AppInventor website, and what's nice about them is that they are actually useful and fun. One of the tutorials is for a map tour of Paris showing attractions like the Eiffel Tower. The tutorial shows you how to incorporate Google maps and even couple the app to your phone's GPS. I personally prefer the programming in the campus map tour I found on YouTube. I made a map of downtown St Louis using my Paint program. This .png file became the background image for my canvas. The little green question marks are sprites indicating interesting sites along the route. Every time you click on a question mark, the canvas visibility is turned off and a picture, address, and short description appears for that site.

I personally think this is a great teaching tool, especially for early learners. Students can program silly little apps, like petting a kitty or painting a mustache on a photo. I've heard a few students complain that AppInventor is boring, but I think that is coming from classrooms where the teacher sits the student in front of a computer with the tutorials and does not encourage (allow?) the student to explore some of the creative (do-it-yourself) challenges. My next task with AppInventor is to write an app to control my NXT robot.

Arduino - Adventure #2

I've been spending a lot of time with AppInventor (more about that later), but I finally got back to the adventures (chapters) in my new Arduino book. Adventure #2 involves controlling a set of 3 LEDs with a potentiometer. This book is setup really well for students in that it takes you through the project in little steps. First, I connected 3 LEDs and lit them up in series (similar to chapter 1, but in triplicate). Then I hooked up the potentiometer by itself and played around with the different position settings. The final activity was to control the illumination of individual LEDs based on the position of the potentiometer. This book is great, because it not only teaches Arduino programming, but basic electronic circuitry. Chapter 2 also describes how to print status messages in the Serial Monitor on the computer screen - a really handy feature when you're trying to debug a program.

The final challenge in this adventure was to build a little electronic sign. This brings in the creative aspect for kids, and I would have constructed my own sign if I would have had a set of markers and some poster board handy. Next time.

Minecraft

I've been trying to teach myself how to play Minecraft. While it's not exactly a STEM-specific game, it seems to be all the rage among kids, so I thought I'd check it out. Minecraft is kind of like Lego in that you try to build houses, but unlike Lego where you start off with a bunch of bricks, in Minecraft you have to dig (mine) for the resources to build (craft) your house. Unfortunately, there is a "day" and a "night" to the game (each about 10 minutes long) and if you don't get some kind of shelter built by nightfall, the zombies come out and kill you. I downloaded this game to my Kindle Fire, but so far I haven't made it through a single "night," because I am too slow.

What puzzles me the most about his game is that there are no instructions. How do kids know what to do? I've spent hours on Google trying to figure out how to make things work (unfortunately, Minecraft "purists" consider this cheating). I discovered that the quickest way to build a shelter is simply to dig a hole in the side of a mountain. Duh. That still doesn't protect you completely from the Zombies, because you still need light and a door, but it's significantly quicker than trying to build a house with 4 walls. I can dig or cut down a tree simply by holding my finger on the Kindle screen, but then I have to "pick up" the dirt or wood or they won't show up in my inventory for later use (who knew that to pick up items, you simply run into them).

I finally figured out how to build a door and a torch for my shelter (I needed to build a crafting table from my wood and a furnace from some stone). Maybe that is why the game is so addictive. There is a certain pride when you finally figure something out, and an incentive to try something new. Some parents might not like the destructive element the zombies impart to the game, but are the zombies any different than my little sister who repeatedly toppled my Lincoln log house when I was growing up?

Thinking Outside the Box

The other day my niece told me that her daughter, Violet, had been kicked out of gymnastics class. Now Violet is only 2-1/2 years old and she's not training for the Olympics. This is simply one of those mommy-and-me type of classes that stay-at-home moms feel the need to enroll their children in. So I wondered, what in the world could Violet have done that would have required her removal from class.

It turns out that the instructor was one of those rigid Type A personalities that we STEM teachers dread. At the beginning of class, she handed out a hula hoop to each student. Rather than twirling the hoops around their waists as the toys were intended, each was required to place his or her hoop on the floor and sit quietly inside the circle while the teacher demonstrated a forward roll. Now when I was growing up, we didn't need a class to learn how to do a somersault. My mom just opened up the back door and we rolled down the hill into the neighbor's yard, but I digress.

After patiently watching the teacher demonstrate a forward roll, Violet enthusiastically jumped up, ready to attempt the gymnastic maneuver. Unfortunately the teacher led her back to her hoop and told her she would have to wait her turn. Now don't get me wrong, I can understand wanting a little bit of order, but there were only 3 students in class on this particular day. The instructor couldn't handle 3 kids doing somersaults at the same time???

After repeatedly trying to confine Violet to her hula hoop circle, the instructor finally gave up and asked her to leave the class. It never ceases to amaze me how some teachers can crush the spirit of a young child with their compulsive need to ensure order and rigid control over a simple exercise. And we STEM teachers wonder why our students have such a hard time thinking outside the box.

Winter Projects

I bought 3 new project books to take away the winter doldrums. Two books are from Wiley Press and have basically the same theme (electronic projects for kids), but they have different platforms. Becky Stewart's book is focused on the Arduino, and Carrie Anne Philbin's on the Raspberry Pi. I also bought Simon Monk's book on programming the Raspberry Pi with Python. These should definitely keep me occupied when the snow is accumulating outside.

I finished the beginning section in the Arduino book - getting the Arduino connected to my computer, uploading a sample program, and getting the onboard LED to blink. Between the book and the Arduino website, I found the setup instructions to be fairly straightforward (though you have to assume that screenshots aren't always going to match exactly given the way operating systems constantly change). There are many Arduino models on the market, but I decided to use the Uno as it seems to be the most common right now. What I like about the Wiley books is that the chapters are called "adventures." They don't just tell you to upload an example file and move on, but they step you through the code explaining each command. Plus at the end of each adventure, they ask you to build something hands-on. In the first adventure, they want you to build your own LED circuit, not just rely on the one built into the Uno. I think this makes it a lot more engaging for the students.

LEGO Cherry Picker

I've been trying to build some of the other designs from the LEGO Remix building instructions published on the NXTStep blog, but there are a few building elements that I'm missing. The one on the left is a 1M beam with 2 cross axles positioned at 90°. It's an incredibly versatile little piece giving you the ability to make connections in 3 different directions. But it is so compact, that I have not been able to come up with a way to duplicate it using the pieces in my EV3 robotics set. The element on the right is a 3M connector. The first unit of length is a traditional friction peg; the other two-thirds are a 2M axle. I've been able to get away with substituting 3M axles for this piece, but having a friction peg on one end makes the connections a little more stable.

The other day I discovered that the Cherry Picker kit comes with 4 of the 1M beams and 2 of the 3M pegs. It was very reasonably-priced from the LEGO store ($12.99), plus they threw in a free NexoKnights mini-fig. The cherry picker is somewhat small, but it has a very clever mechanical gearing system to raise and lower the boom. It only uses a 24T gear and a worm gear (the black 12T gear is not part of the gear train, but is simply used as a turning handle). What a great teaching tool for kids.