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.