Merry Christmas Eve

Pitsco has a guide on their website for building a spinning Christmas tree out of their Tetrix Prime Robotics Set. Their design uses elements from both the starter set (beams) and the expansion set (linkages). They even include a file for 3D printing 2 specialized parts for constructing the center support. But don't worry if you don't own a 3D printer or have time to run down to the local STEM center. There is also an option to build the center support out of wheels and axles (shown here). By adding a battery-operated set of LED lights, I've got a very festive (if somewhat nerdy) centerpiece for our Christmas table.

Science Journal App

I found out that Google's Science Journal app for Android phones can now be used with Vernier sensors and since I have a closet-full of Vernier sensors, I thought I'd try it out. Science Journal was originally created so that you could graph data from the sensors built into your Android phone (sound, light, motion, and barometer). The app is very easy to use, but limited in its analysis capabilities. What is nice, however, is that Google is encouraging 3rd-party vendors (like Vernier, Sparkfun, Jameco, and Pocketlabs) to develop compatible products and kits that capitalize on the features of Science Journal.

I tested Science Journal with Vernier's Go Wireless Temperature sensor. This waterproof Bluetooth device has a temperature range of -40 to 125°C (-40 to 257°F) with an accuracy of half a degree. The battery charge lasts about 2 hours, but you can easily recharge it with the same USB charger you use to charge your phone. You must have Vernier's Graphical Analysis app installed on your phone in order for their sensors to communicate with Science Journal, but once you do the initial setup, the Vernier sensor icon shows up right next to the Android sensor icons. Truthfully, having used both apps for data collection, there are times I would use Graphical Analysis over Science Journal, like when I need to do curve fitting or statistical analysis beyond the basic min/max/mean. But Science Journal is a simple way to couple my closet-full of Vernier sensors with the sensors in my phone.

Electrical STEAM

I recently stumbled on a few interesting products while volunteering at a STEAM workshop for Art Unleashed. Art Unleashed is a non-profit organization that has been incorporating science and engineering into some of their more traditional art classes for kids. Earlier this year, they offered a Saturday workshop on electricity. The kids made greeting cards accented with LEDs that lit up. They drew simple circuits onto card-stock using bare conductive paint from Sparkfun. This water-based paint conducts electricity eliminating the need for wires between the LEDs and coin-cell batteries. The paint comes in little squeeze tubes, so it is very easy to apply; but the paint has to be applied fairly thickly and it takes a long time to dry, especially in humid weather. This activity would work better spread over a couple days, so the paint can dry overnight.

Next we had the kids create light-up animals with Playdoh and modeling clay. The Playdoh is conductive, while the clay acts as an insulator. This is an excellent way to demonstrate the difference between a series circuit and an electrical short, because the LED won't light up if you just stick it and the battery into a single lump of Playdoh. Normally, you wouldn't connect an LED directly to a 9-volt battery or it would immediately burn out; but since the Playdoh has such high resistance, you can create circuits without the need for adding traditional resistors. Just be sure to have extra LEDs on hand for those kids who accidentally burn out their LEDs. I tried this activity with the off-brand Dough from Dollar Tree (4 different colors for only $1) and it worked beautifully.

For fast finishers, we set up stations with Snap Circuits. Snap Circuits are electronic elements mounted on big squares of clear acrylic - kind of like electronic jigsaw puzzle pieces. Kids snap the various elements together to create electrical circuits. We used the Snap Circuits Jr kits, which contain instructions for creating 100 different circuits from over 30 elements, like switches, sensors, lights, sounds, motors, etc. I'd heard about Snap Circuits at conferences, but never had a chance to try them out. I was so impressed, I bought my own set from Amazon (less than $20) and tried it out with my 4-year old niece. She loved it, especially the flying propeller.

Prime Expansion Set

I bought the new Tetrix Prime Expansion Set during the Cyber Monday sale at Pitsco. Unlike the Starter Set which primarily contains aluminum beams and plastic brackets, the Expansion Set includes a wide assortment of aluminum linkages, plates, and gussets. One major advantage is that you can use the linkages to make walking robots. 

The building instructions for the WalkerBot (shown above) are included in the user manual. I think it "loosely" looks like a reindeer - very apropos for this time of year. This model was significantly more difficult to build than the introductory models in the Starter Set. The premise of a linkage is to transfer the motor's rotational motion into linear motion, however if you don't get the linkages lined up perfectly, the whole model just locks up. It took a little finagling and re-positioning of joints to get the model to start walking. Once it did, its gait was rather clumsy and lumbering - kind of like a cockroach after a few cocktails. I haven't tested WalkerBot with kids yet, but I suspect the slowness of its awkward gait may not be as exciting as some of its wheel-based counterparts.

Tetrix Robotics Camp

I'm teaching 3 robotics camps this summer. All are based around the Tetrix Prime set - a remote controlled system. But each camp has a little different flavor, because I have 3 very different audiences: teachers, middle schoolers, and high schoolers. I've discovered that teachers love to build the robots, but are reluctant to drive them (fear of not being perfect in front of a crowd???). Kids slap the models together as fast as they can and race out to drive them. It doesn't bother them if a part or two falls off when their robot collides with another (matter of fact, that sends them into fits of hysterical laughter).

I get most of my ideas off the TetrixRobotics.com website, either in the Build section or the Video section. I use these as a starting point to introduce a concept like gear trains or joystick control, and then present a challenge to the campers that would require some individual design or game strategy. I'm trying out a few new models this year, since some of my campers will be returning. The one on the upper left is called InchBot. If you maneuver the joystick just right, you can get him to move along in a straight line, but mostly he inches up and down while moving forward. You have to be careful you don't lay him out flat or you can't get him back up. I call the one on the upper right DetectorBot. It's just a square chassis with an NXT light sensor suspended from the center of the base. The NXT has a very simple program to beep whenever the light sensor rolls over a little blue square of painters' tape. This robot takes a lot of patience and concentration, because he's a little harder to maneuver than you might think.

The device on the lower left is called MazeBot. I saw this in the Pitsco booth at one of the STEM conferences last year. It took me a while to figure this one out, because unlike Pitsco, I don't have access to unlimited parts. It takes almost every beam and connector in the box, but I managed to create this design with only one kit. The campers construct their own mazes out of cardstock and mount them to the center frame. Then they try to see who can get the marble through the hole the quickest. The device on the lower right is called KickerBot. It's a great training tool to practice getting the timing right to connect with the ball and get a good hit, but then I challenge the campers to come up with a way to put a kicking mechanism on a mobile chassis so we can play robot polo.

The last day of camp is our ultimate challenge - meant to emulate NASA's Curiosity rover on Mars. The campers have to build a robot that can retrieve the stranded astronauts (minifigs), find water (blue tape squares), clean the dust off the solar panels (4x4 bricks), and exchange the dead power boosters for fresh ones (wheel and axles torn off some old pinewood derby cars). It's a lot of fun and a great way to impress the visitors who show up for parents' day. I really like the Tetrix Prime kit, because their quick rivets and thumbscrews make it easy to assemble and disassemble robots quickly. We average 2-3 robots a day, which would be nearly impossible if we were using traditional nuts and bolts.

LEGO WeDo for Chromebook

When I attended the Engineering Educators' conference last month in New Orleans, I talked to the LEGO rep and found out they were getting ready to release a Chromebook app for WeDo 2.0. I just set mine up today and I must say, it works beautifully. The only little "glitch" was getting the software to find the SmartHub. My Chromebook found it instantly, but I had to turn Bluetooth on and off a couple times to get the software to recognize it.

LEGO Education has a special going on right now. If you order the WeDo 2.0 Core Set, you also get the curriculum pack ($290 value) for free. I really like the built-in tutorial section of their software. It includes 4 Getting Started activities, 8 Guided Projects, and 8 Open Ended Projects. The Getting Started projects teach you how to build a little rover, get it moving, and operate the motion and tilt sensors. Another nice thing about the software is the built-in capability for kids to keep a log of their designs. There is a camera function that allows students to incorporate stills, video, or screenshots alongside their text-based reflection statements.

The only down side of the software are the Help videos. None of them contain any written or spoken words - just some background music and a lot of pantomiming by 2 minifigs (Max and Mia), Sometimes it's hard to figure out what they are trying to tell you.

I noticed that there is an Android app for WeDo 2.0. I may try to check this out on my phone, since I feel a little funny chasing after my robot with a Chromebook.

Arduino and Servo Motors

With electronics, there is only one mantra to live by... baby steps. My ultimate goal is to control 2 standard servo motors with an accelerometer (details on the actual project later). I started out by wiring up 1 servo motor to a potentiometer and then writing a very short program like that described in Project 25 of Beginning Arduino by Michael McRoberts. I wired the center pin on the pot to pin A0 and the servo signal wire to pin D5. The jumper wires I got from SparkFun Electronics make this so much easier to do than the alligator clips I usually use.

Next, I disconnected the pot and replaced it with an analog protoboard adapter from Vernier Software & Technology (same wiring). Vernier sells a 3-axis accelerometer, but I just plugged in the x-axis for the first pass. The servo arm responded to the movement of the accelerometer, but I didn't have the full 180° range of motion. (Have to figure out why...)

Incidentally, I discovered something about using servo motors with the Arduino board. I knew you controlled servos with Pulse-Width-Modulation (PWM), but I didn't realize that not all digital pins on the Arduino board provided that. Only the ones with the tilde ~ next to them provide PWM. A useful tip for the day.

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.