Category Archives: STEM

Tetrahedral Kites

Several different tetrahedral kite drinking straw designs were tried to see what would be easiest to build.
Several different drinking straw designs were tried to see what would be easiest to build.

After the big winds a few weeks ago, we decided to build some kites for our latest Castlemaker Kids project. For those not familiar with tetrahedral kites, the engineering behind the geometric design and history of Alexander Graham Bell’s involvement is interesting.

Alexander Graham Bell saw the Tetrahedral Kite as a way of getting to manned flight. Just before the turn of the 20th century, there was a big debate in the scientific community on whether human flight was possible. Kites were being used to test aerodynamics and flight stability for possible aircraft. After Lawrence Hargrave developed the box kite in 1893, Mr. Bell designed a tetrahedral kite in 1895, which was not only very stable but simple to expand and easy to fly. Mr. Bell wrote a National Geographic article in June 1903 on his new kite structure that explains the development and gives a comparison with other designs. He eventually created a steamboat towed 12 meter (40’) long 3,393 cell model in 1907 that carried a man 51 meters (168’) above the water!

Prototype tetrahedrons and cutout tissue paper. Building a template helps considerably. We used string to tie the straws and cells together, but I'm working on designing a 3D printed connector to see if that would work.
Prototype tetrahedrons and cutout tissue paper. Building a template helps considerably. We used string to tie the straws and cells together, but designing a 3D printed connector to see if that could work.

There are lots of variations today – the design we chose was built using drinking straws, string, and tissue paper (Tyvek also works). Individual tetrahedrons are made out of straws, tissue paper is put on 2 sides, and then they are tied together in groups of 4 to make a building block. The 4 cell model can fly by itself but if you get ambitious 10 cell modules work well too, all of which could be attached together into larger tetrahedral kites. Instructions for a simple 4 cell model can be found here, but it can be tailored to the supplies available and what you’d like to build. To help with the kids’ attention span (and time constraints) we stayed with a 4 cell model.

Brian holds up his completed kite by the bridle. He used just one longer string for the bottom layer, the rest of us built individual cells and tied them together.
Brian holds up his completed kite by the bridle. He used just one longer string for the bottom layer, the rest of us built individual cells and tied them together.

Finding non-bendy straws locally turned out to be a challenge, each 4 cell module takes 24 straws. The rest of the components are pretty straight forward, it’s just a matter of time and patience to assemble a kite. Once you figure out the pattern, the most difficult part is tying together the individual tetrahedrons with the string, in the version we used. There are several other versions if you search the internet, including one that uses flexible drinking straws, but the individual cells in the folding model are wired together. This makes assembly a bit more challenging and I found it harder to put and keep together, although the folding feature is nice.

A tetrahedral kite’s advantage is the low weight to sail ratio. Because of the shared trusses, as you add additional cells performance improves – what Bell saw in this design over other types of kites. And it’s easy to put multicolored paper on the kite, making a good looking kite. Don’t be surprised if you see some larger ones in the sky this summer in Putnam County!

Teaching With 3D printing

The whistlers share their designs and prints. The train whistle in the foreground didn't turn out as planned, something every engineer has experience!
The ‘whistlers’ (Ben & Carlie) share their designs and prints. The train whistle in the foreground didn’t turn out as planned, something every engineer has experienced!

A high school Principles of Engineering class I visited last week is providing a great example using a 3D printer to teach the engineering design process and critical thinking.

Mr. Shields at Greencastle High School inherited a 3D printer when he took over a new class this winter. I had contacted him to see if he or his students were interested in a community 3D printing competition that Castlemakers is putting together. He was able to take the basic idea we had and turn it into valuable classroom experience for the students. Plus provide a pilot test for a future community 3D printing event!

Another student demonstrates his 3D printed frog, which resonates sounding like a 'ribbet' when a stick is rubbed on it's back.
Craig demonstrates his 3D printed güiro, a frog which resonates ‘ribbet’ when a stick is rubbed on its back.

The challenge was to 3D print a functioning device that would make noise or music. They had to walk through a seven step design process, print the part, and then write a report that included evaluation of their prototype by others.

The projects they made were impressive with whistles, a drum, ribbiting frog, and of course musical instruments. While all of them were good, perhaps the most impressive sounding was a musical instrument that 2 students collaborated on – Mattia designing and making a mouthpiece while Dalton did a horn. You can hear the mouthpiece/horn in this video.

Justin B assembles his banjo/ukulele. One of his tuning keys broke but of course another can be printed!
Justin H. assembles his banjo/ukulele. One of his tuning keys broke but of course another can be printed!

Piaget would be proud of the constructivist learning going on Mr. Shields’ classroom. It really shows how hands on learning and the maker movement can improve learning in the classroom. IU School of Education is embracing the movement, opening a new a makerspace(The MILL) last fall in the Wendell Wright Education building just for teachers. Not all learning goes on in a classroom however, and people need tools/equipment and a place to practice – one of the reasons that Castlemakers feels Putnam County needs a makerspace.

Building A Robot at Wonderlab

Wonderlab/Bloominglabs workshop on building a light seeking robot from motors, switches, and a few electronic components.
Wonderlab/Bloominglabs workshop on building a light seeking robot from motors, switches, and a few electronic components.

Another good regional resource for kids STEM activities is Wonderlab in Bloomington, Indiana. Besides being a fun place to visit, they also offer summer day camps for kids through 6th grade (and mentoring opportunities for those older) that can range from crazy contraptions and electronics/engineering to TV technology. They also have occasional special events, often on weekends or during school breaks, that anyone can sign up for.

A completed 'BrainBot' - light seeking robot based on the SunBEAM seeker robot.
A completed ‘BrainBot’ – light seeking robot based on the SunBEAM seeker robot. These use $7-8 in parts and the robot seeks out light using the two photosensors that drive the rear motors.

Bloominglabs, the community makerspace in Bloomington, put on a 3 hour Brainbot building workshop over spring break at Wonderlab for kids and adults. Since we had some experience teaching kids to solder, ended up helping with the workshop and now helping to improve the workshop instructions. Bloominglabs also helps the Monroe County Library with speakers for the summer Make It Digital series, put on Makevention every year, and have an open shop night every Wednesday evening for those interested in making.

As we work towards creating a Putnam County makerspace, the robot building workshop is a good example of what Castlemakers will offer. Of course a makerspace is much more than just classes. But the goal is sharing/helping people to learn skills with arduinos/microcontrollers, mechanical devices, 3D printers, and more. And with the right physical location that may include welding, woodworking, jewelry making… all things that makerspaces in other cities offer.

Catapulting a Wild Boar

Yes, that is a flying pig in the photo! After working through the calculations of a hurling a wild boar, the students got to try firing various animals at a castle wall.
Yes, that is a flying pig in the photo! After working through the calculations of a hurling a wild boar, the students got to try firing various animals at a castle wall.

Yesterday, in conjunction with The Castle, we did a class workshop on catapults with the 7th grade science students at Greencastle Middle School. They were challenging sessions with both physics and mathematics involved, but the kids in the 7th grade science classes on Friday worked through the calculations to solve whether a 150 pound wild boar could be hurled across a 100 yard moat using a catapult. Their current curriculum was in the Newton’s laws of motion section, which they had to use to help answer the question.

With only a 43 minute class period to work with, we had to reduce the scenario to a fairly short calculation. The groups were given the wild boar launch velocity (100 ft/sec at a 45 degree angle) and had to calculate the flight time so the total distance traveled could be determined. For those that finished the problem quickly they could try to figure how the distance would change if a cow was instead launched, but that was a bonus item that most didn’t get to. We finished up by test launching a few stuffed animals in the classroom to see a simple catapult in action.

Special thanks to Mr. Wickerman for letting us into his classroom, to Kara Jedele from The Castle for arranging the workshop, and both Kara and Emily Knuth for helping in the classroom.

Learning to Solder – Part 2

Newspapers were used since they quickly smoke/smell if a soldering iron is left on the table. The chaser kits are sometimes called a Larson Scanner referring to Battlestar Galactica & Knight Rider.
The chaser kits being built are sometimes called a Larson Scanner referring to Battlestar Galactica & Knight Rider.

Despite the snow & cupid competition, we had some not-so-lonely hearts show up yesterday to continue learning and honing their soldering skills. This was our 2nd soldering session, during the first one the kids learned first by soldering wires together and then went on the kits. A little simpler kit with color changing/blinking lights was used this time for those that missed the first meeting or were quick to finish.

Newspapers were used to quickly smoke/smell if a soldering iron is on the table.
Newspapers were used on the tables, they quickly smoke/smell if a soldering iron is on them.

The LED chaser kit (Velleman MK173 rev2) was a medium difficulty build; in retrospect something easier for first timers would be better. But the coolness factor is very high, you can see it in this video link to Connor’s just after he finished. The socket helps protect the IC from overheating, but 44 solder joints is a lot to do. Solder pads are close together on both kits, not unusual, which offered opportunities for many kids to learn unsoldering techniques (some more than others). Glad we had a couple of solder suckers to clean up the bridging and over ambitious solderers! We also had one solder pad on one of the boards come loose but hard to tell if that was a circuit board problem or not.

Another completed RGB LED blinking kit.
Another completed RGB LED blinking kit.

The color changing LEDs kit (Lux Spectralis 2) was definitely simpler with 24 solder points, but was bought on clearance so now hard to find. It has 38 modes of color/flashing to choose from and could be easily finished under an hour or less. The IC (ATtiny13a, no socket included) held up well to overheating, least from our experience. One kit was short a few parts, something we’ll plan for next time.

We’ll be doing more learning to solder classes, this is a skill that generated an lot of interest from both young and old. Our next meeting will be using App Inventor again, part of our series building up to Arduinos and other microcontrollers.

Learning to Solder

Our first ‘learning to solder’ session last Sunday drew quite a crowd. With 20 kids showing up and quite a few parents there too, we packed the FYCDP house on Crown Street. George Edenfield, who’s involved in Putnam County Auxiliary Communications and an active amateur radio operator, helped lead the session. Many of the kids brought their own soldering irons or borrowed one from a parent, but only a few had ever soldered before.

Before tackling the circuit board and real electronic components, the kids practiced on soldering wires together.
Before tackling the circuit board and electronic components, the kids practiced on soldering wires together.

After going through the basics and soldering safety, George had everyone solder two wires together so they could learn how to handle a soldering iron and learn how to recognize a good soldering joint. We then moved on to a small kit that creates a ‘chaser’ effect in 6 LEDs. The kids picked it up pretty quickly, although most needed someone to help them with the first soldering joint on the small circuit board. A few even got to learn how to use a solder sucker (desoldering tool) when they got a little carried away putting solder on the copper pads on the circuit board. Desoldering techniques, a possiblebackup topic if there was extra time, will be covered at a future meeting.

Another table starts their initial soldering task.
Another table starts their initial soldering task.

Although the kits didn’t get completed due to time and everyone helping each other, everyone kept saying how much they liked it and wanted to do more. So we’ll continue working on those that didn’t get it completed at our next meeting, February 14th, and for those that did or missed the Jan 31rst meeting we’ll have another simpler, quicker soldering project. It was so popular we ran out of the chaser kits.

Building Phone Apps

On Sunday, January 17, about a dozen kids learned the basics of coding by building some Android phone apps. We met in a computer lab in the Julian Center at DePauw, and worked through some of the tutorial apps in the App Inventor program from MIT (http://appinventor.mit.edu/explore/).

Screen Shot 2016-02-05 at 10.55.57 AM
Alice Howard’s “Magic 8-Ball”, which randomly says “Yes” or “No” when shaken

The system is programmed through a web browser, where you can build how the app screen will look (with buttons, labels, and connections to various phone sensors), then shift over to a “blocks” environment where the actions can be hooked up. The first example involved responding to the phone being shaken by sending some text to the speech synthesizer (such as, “Hey, stop shaking me!”).

While the app was being developed in the browser, an Android device (some kids brought phones, and the CS department loaned a bunch of tablets for the afternoon) was attached to the session and allowed immediate live testing of the program.

Screen Shot 2016-02-05 at 11.03.52 AM The second app we built was like a virtual billiards table. It drew some balls on the screen, and with a flick of the finger they could be launched to bounce around.

The App Inventor website allows sharing the projects that are created, and they can be turned into stand-alone apps to download to a friend’s phone. At the end of the hour, a bunch of the kids were excited about being able to continue working on their app ideas at home. Alice turned her random yes/no app into one that could generate a random story idea for a Doctor Who episode (example: “The Doctor and Rose battle the Daleks in New New York, accompanied by Captain Jack.”), and then worked with a friend to build a pair of apps that told each other knock-knock jokes (using a speech recognizer as well as the speech synthesis)!

App Inventor is related to the Scratch environment, which can be used to control Arduino boards, so it’s likely that there will be more sessions like this in the future.

Cardboard Virtual Reality

Google Cardboard Kit components. The magnets become a switch for the cell phone's magnetometer.
Google Cardboard Kit components. The magnets become a switch for the cell phone’s magnetometer.

Today we assembled some really inexpensive Google Cardboard kits and explored different 3D virtual reality programs that use a cell phone for viewing. By using the cell phone gyro for judging head movement and the magnetometer as an input device, with a little cardboard and a couple of lenses you can experience virtual reality!

We started with some ‘un-certified’ Google Cardboard kits, I suspect these are version 1 models vs. the latest version 2. These do not have the QR code that can help with configuration. These particular units don’t come with any instructions, which since they don’t strictly follow the Google Cardboard guidelines, made a little more challenging build. But really not that hard and adding some masking tape made them even sturdier. And they do work!

Rebecca discovers that the view is 360 degrees by looking up at the sky.
Rebecca discovers that the view is 360 degrees by looking up at the ‘sky.’ The adults are exploring what additional apps we can try.

The real fun began after Alice got her’s assembled first and then began wowing… everyone else starting racing to finish theirs. The technology is impressive and the demo app is a great place to start. There are so many more apps out there already that it will take some time to learn the best ones. Some of us old folks liked the Paul McCartney video app where you are on-stage for one of his concerts and can look around 360 degrees to watch things from the band perspective. Impressive fireworks and sound too! The VR Roller Coaster app was a hit with the kids, although I think all of them also tried the different cities in the demo, starting with Paris where you can walk around the Eiffel Tower.

Testing the Ozobot

Experimenting with ozobots & cubelets
Dunkin works on one of the prototype tests for the ozobot. A few cubelets are in the lower left corner.

In today’s meeting we looked at ozobots & dug out the cubelets to try and get the Bluetooth control working. Technical difficulties prevented the cubelets from  working with the remote control app. But the ozobots were a bigger hit anyway with both the kids and adults there.

Ozobots are tiny dome like robots that have optical sensors that are used to follow lines. These lines can also program the little guys, through shapes and colors. Using a marker they will follow the line you draw but by using different color patterns they will change speed, change direction, pause, stop and even count.

Castlemaker kids try an ozobot on the maze they created
Path that the kids developed to test the ozobots. In this trial it’s not doing so well, but has a chance to redeem itself if it gets the square root of 1 correctly, otherwise it goes into the “imponderable death of doom.”

It was amazing to sit back and watch the kid’s creativity. After a brief introduction to the ozobot, the kids discovered much more on their own. Following mazes and lines drawn on paper, along with guessing which branch the ozobot would take dominated the afternoon.

The kids decided to “test the robot’s artificial intelligence” by creating questions that the robot could ‘answer’ by choosing the right path. The maze they created started with simple questions like 4 divided by 4, then progressed into more difficult questions like which country created french fries. There were plenty of death traps and black holes along the path for the ozobot if a wrong decision was made. They decided to conduct tests for both ozobots , you can watch one trial in this video. Of course the robot didn’t really evaluate the questions, just took a random path, but they still had fun.

Castlemakers_Ozobot_Maze
The final test path they created. You can see one of the ozobots following the line near the top of the picture. In this trial it picked the correct answer for 4 divided by 4 and even chose the robot vs. human path.

The ozobot color changing capability was a huge hit (different colored lines cause the bot’s LED to match the line color). They are somewhat sensitive to line width, but it’s not a huge factor. The large dry erase board attempt didn’t work well, the bot would eventually scrape off some of the marker then stop. Ozogroove, the dancing app, was pretty useless on a Nexus 7 – don’t bother to install it on that tablet at least.

We’re going to have to experiment some more with hand drawing the ozocodes, the programming language for the robot. It seemed to be inconsistent, sometimes working and sometimes not, even for the same color coded lines. Printed ones worked great. There’s also a coding language, ozoblocky, but that will be a future meeting.

Model Rocketry in Putnam County

Rocket launch picture
Rocket being fired from pad #2, which was for some of smaller rockets.

Rocket launching was the theme of the day last Sunday for the Castlemakers that could attend. Nick and Emily Adams extended an invitation to a Rocket Launch at their place south of US40. Four families, along with some invited friends and Castlemakers got to see a wide variety of solid propellant rocket launches in South Putnam County.

Pad #1 was used for some of the larger rockets. Up to size G rocket engines can be used without FAA approval.
Pad #1 was used for some of the larger rockets. Up to size G rocket engines can be used without FAA approval.

Amateur rocketry has been popular for years; many people will remember putting together Estes rockets as kids growing up. That still continues, with additional firms involved, with more gps units, cameras, electronics and even Arduino boards. Many of the tools used in a fab lab/ makerspace are being used! For an example check out the Carbon Origins effort (10,000 feet & Mach 2 before breakup); their story was detailed in a recent article. We didn’t see that kind of launch on Sunday, but there was a video of a Mach 1.5 flight Gus hit the day before at a site near Chicago (and he does a lot bigger rockets).

Gus Piepenburg mounts a camera on the side of number 13 before launch. It wasn't the lucky number of the day, the landing didn't go well and it will become number 14 with some improvements.
Gus Piepenburg mounts a camera on a model CM-10 Bowmarc before launch. The flight didn’t go well, landing in several pieces, and after changes it will become number 14.

What we did see on Sunday was incredible. There were four families that had built multiple rockets, all involved with Indiana Rocketry, and there were two launch pads and 4 towers to launch rockets. I noticed several with GPS units (one hit 2500 feet) and several had cameras. One even had the infamous 808 keychain spy camera, sometimes used in robotics, that had a 3D printed camera case on the side of the rocket.

The local Putnam County 4H has a rocketry group if you’d like to get more involved, or you can also contact the Lafayette-based Indiana Rocketry club which has even more information.