# Quick Design Communication & Woodworking Project – 2×4 Challenge

There often comes a time in my class, especially with my 8th grade, where students get restless and feel like they haven’t done anything ‘hands on’ in weeks. Sometimes that’s true, we’ll be buried in our PCs learning more CAD concepts or working on project reports, and sometimes that isn’t all the true. Either way, there comes a point where I know we need to get tools into the kids hands.

Wrapping up my first year teaching Project Lead the Way’s Design and Modeling course, my students had completed most of the curriculum. They had gone through sketching, into CAD modeling and had become very capable communicators of their ideas. I wanted to create a project that was fast, that they could quickly model in CAD and then fabricate as soon as they had a clear CAD model.

…in a bit of a selfish need, I also knew I wanted to get rid of nearly a pallet of 2x4s that were taking valuable woodshop square footage. I think they were from an old catapult project, but I honestly have no idea. There were a relic that came with the shop when I came through the door.

So the design challenge was simple. Students could fabricate anything they wanted out of a 48″ length of 2×4. The only constraints were that they could only make crosscuts and 45 degree miters in a miter box. They were tasked with creating a design model and a complete cut list, and with that completed, they were allowed to grab a board and head over to the miter saw stations (after completing a safety check off).

The project was an awesome success. Students went on to learn construction using drills and drivers, and put down a coat (or a few to many coats) or spray paint to make their final designs. They weren’t always pretty, or complicated (it isn’t easy to do something to crazy with only rough cross and miter cuts), but they designed, fabricated and finished by the students.

I even went on to repeat the project with the 6th grade, with a few more constraints and using another stockpile of 1×2″ scrap boards. They were able to design quickly in Tinkercad, show their designs created with only miter cuts. They were also given the theme constraint of ‘yard games’.

There are a couple of take aways from this project now that it is completed. Firstly, students need some constraints to function. My 8th grade had a massive amount of issues when I told them they could make anything. Once a few theme ideas and examples were thrown out, they very quickly got themselves moving, but the limitless options got them stuck.

Secondly, finding a way to meld design communication into a tangible build brought out motivation in every student. Knowing they had the tools and materials ready when their design was complete had students pushing hard, even graciously accepting my critiques of the designs and getting back to work to revise them.

Third, once the design was out of the way, the cutting and assembly became play. It took me awhile to realize what was happening in the room, but once I saw it, I knew everyone was having fun. The students were playing. Safely, obviously, but they were moving around the room, they were putting in work to rip through the 2x4s. They were taking turns, having friends take over the cutting after they got tired.

This is a project I’ll be keeping in my back pocket. It was quick, inexpensive, effective and most importantly, it was fun. With the semester wrapping up, I’m even looking to move it further up in the next semester, letting students dive into it almost straight away.

# Laser Cut Bowls For Fun and For Good

Each year, we do a fundraiser for local food pantries and homeless shelters. The aim is to raise awareness, and help address hunger in our local area. An integral part of this fundraiser are decorative bowls that are given out as keepsakes of each years events. This year, I was tasked with producing bowls, and needed to splice this task with getting the 6th grade confident in 2D design and laser cutting.

The result is simple laser cut bowls made of concentric layers that are rotated and glued to create the final form. The design process is simple and comes out intricate and quite beautiful.

The designs are done in Gravit.io, an amazing vector illustration tool that runs perfectly in the browser. To get my students into designing quickly. I put together a step by step guide, as well as a walkthrough video that you can use easily to get going. You can see the video and the guide here.

This lesson took two 70 minute periods, one to design and one to assemble. Most of the laser cutting took place outside of classtime in order to keep the project moving forward, but could certainly be done during class time with each bowl taking no more than 10 minutes to cut out. It would be a perfect introduction to the operation of the laser cutter as well.

In the end, these bowls were huge hit. In fact, we were asked to make an additional batch of 15 in a bit of a larger size as gifts for hosts during an Upper School exchange trip. It is certainly one of those rare and wonderful successes in the space this year.

# Game Design & Unfettered Creativity

We’ve just begun a new semester, and the 7th grade are starting the semester with a unit on Game Design. The objective is to highlight systems level thinking, slip in some engineering concepts, and transition to some computer science in the form of video game development. However, I’ve tapped into a level of creativity I haven’t seen in my classroom before.

We started this whole unit by building a simple game. A ‘Race to the End’ game. Inspired by Game Design Concepts by Ian Schreiber, the challenge was to build a simple game whose objective is to reach the end of a path. Then, students add a theme, add conflict and make these game their own, adding their own creative twist.

And boy did they. Nearly every game involves a physical component I would have never though of. Students are playing the role of the famous school house ghost, Priscilla. Students are being forced to ‘smell the trash can.’ There are jumping jacks being done in the back of the room. Spontaneous singing. Some perhaps cross the line, but largely, kids were being kids and fun was being had. Sure, some marker end up on some faces, but that was a small price to pay for the kind of engagement that was happening in the room.

At the end of the day, I’m super happy with a project that let students run in whatever direction they wanted. The balance of a bit of structure with enough open-endedness allowed for meaningful engagement. As we carry the skills that we learned with this game into another, perhaps even more open ended board game, and eventually into developing video games, the fun that was sparked with this project will carry them through to even more amazing end products.

# Design Challenge: The Foam Wood Derby

I’ve always wanted to run a super face paced pinewood derby style race. As I designed some simple, messy projects for the 8th grade as sort of fun one off projects, I decided to make the idea a reality.

The design is simple. Each group (or individual if your group is small enough) has two deliverables. A car carved out of foam, and a top and side drawing of the car. They get a basic set of materials. A block of floral ‘wet’ foam, 2 axles and 4 wheels. And they get a simple set of tools. Basic measurement tools, speed squares and surform carving tools.

I introduced the challenge quickly, then let the students loose. To avoid having students completely destroy their blocks instantly, I made the drawings a prerequisite to getting the carving tools. The drawings could be simple, but I required a detailed full scale engineering style drawing.

Once the drawings were approved, they were off to the races. However, floral foam is mess. Super messy. I had complaints of allergy like irritation, the foam staining white shirts, dust in their eyes. All sorts of things. However, after stressing caution, using aprons and generally being more mindful, those complaints dropped off. Perhaps this would be a good project to do in a larger space or even outside.

With the designs carved, students were free to attach their axles and wheels. I could have stopped the groups and stressed the importance of being patient with this step, being precise and ensuring straight and square axles. However, I let them at it, though I did stress that our speed squares would be a great benefit to this step.

The axles and wheels came from Pitsco. Sure, you could 3D print wheels if you have the time, but laser cutting in wood was too soft and acrylic was too brittle. A soft thermoplastic is what these wheels need to be made of, and at \$0.15 a piece, it was worth avoiding the headache.

Finally, we race. I used a scrap board at first…but we really needed lanes as cars continued to collide with one another. I used some foam board to make short walls hot glued to the edge of the board. Problem solved.

A simple single round elimination was enough to have a good final race, while minimizing the winners vs losers. You can even enforce a ‘When you lose, you become a cheering squad member of the team that beat you’, ensuring an exciting final race while making all of the students feel a part of the races through the end.

Finally, have students reflect on the process. I had a short discussion, then had students go and post to Seesaw. I got lots of really awesome reflections, lots of great critical thoughts, some great doodles and awesome photos.

Looking back, this little design challenge went pretty well. The kids loved it, it was inexpensive (~\$1.50 per group), and was quick to run. In the future I think it could be slowed down to highlight the engineering drawings in more detail, perhaps print wheels, and focus on nice and straight axle holes.

 Part Cost Cost / Kit Source Floral Foam (72 when halved) 35.50 (price fluctuates on amazon) 0.50 Amazon Pitsco Axles (100) 6.50 0.13 Pitsco Pitsco Wheels (100) 15.50 0.62 Amazon TOTALS 57.50 1.25

Surform Tools – \$2.99

Speed Squares – \$2.99

# 3D Printers as Construction Toy Factories

The 3D printer is the hottest tool to bring into classrooms these days. They are the talk of the town. In lots of ways, they are amazing machines. It possibly more ways, they are tricky classroom tools. Most of them take plenty of tinkering and tuning, print times are long (a 1 hour print for all 50 students in a grade can be a week or more in the making), upkeep is time consuming. Lots of little quarks.

However, where they have excelled in my classroom is in printing construction brackets. If we aim to print small parts to be used to let students build bigger structures you can kill a few birds with one stone. Print times are reduced, and you have a build to pull students away from the computer screen.

I wanted to share a few examples, and how I use them in my classroom. First up, the simplest. Brackets to join straws at different angles. I took inspiration from Makerbot’s Speedy Architect project for this one. These pieces are tiny, taking less than 10 minutes on our Printrbot Simple Metals using my super-duper fast printing profile. Currently, the 6th grade is designing architectural models using these brackets. They will be adhering to uniform proportional scale for the structure (about 1″ to 10′), and will be closely monitoring a the cost of production. Straws cost \$100 per inch, and 3D prints cost their real life cost, times a thousand, or about \$20 per basic bracket.

I’m super excited to see how this project turns out. There are lots of great math connections to the 6th grade curriculum using the scaling and the economy system. The structures are bit innocuous from the structural engineering perspective, but the amount of iterative design & 3D printing we can pull off while printing such small parts will make this project worth while. We are lucky enough that each of our groups of 4 will have their own 3D printer to operate during class time, keeping the project rolling at a fast pace.

Up next, there are the balsa wood brackets, that came from the Zazouck project on Thingiverse. These parts are a bit different than the straws in that I use them exclusively as construction tool. The parts are all printed ahead of time, sorted into different types and they are used to do rapid fire construction challenges. Most recently students were tasked with building a 12″ bridge, while controlling for the cost of parts and materials used to build the bridges.

These pieces are great for rapid construction. They lack in the structural consistency that using glued joints might give you, but they let students build quickly. Often, balsa breaks in the brackets, but a drill bit reams them out pretty easily. These are great bits, and took about 30 mins to print a set of each piece. To get a classroom set of about 20 of each part, I had the machines running constantly for a few days. But now they are done and we have our own custom construction set…in colors that match the labs floors!

Last up, we’ve got the most complicated component yet. The craft stick brackets. These pose the most difficult design process of the three, but I think it gives the most rewarding final product. Requiring constantly being aware of stick orientation in regards to slot location on the brackets. I think the challenge of the design makes these an awesome candidate for creating a lesson on using Fusion 360 assemblies to virtual design structures before printing them. This is something I’ve got in the pipe for the 7th grade next semester.

All of these follow a basic principle. Find a material that is cheap and plentiful in you lab, and design brackets to join them at different angles. Have students design the parts, even model the whole structure in CAD before printing. Cut down print times, end up with bigger and cooler parts…its a win win all around. Have you done any construction projects like this? Let me know!

# Simple, inexpensive classroom woodworking projects.

I’ve really taken to woodworking this year. I think the ability to transition from high-tech to low-tech in the same space is a powerful experience for my students. Using the lovely mini-week program, I had 7 students for 3 full days of nothing but woodworking. We had a blast, and made lots of amazing things. Today, I want to take the time to show off some of these simple woodworking projects that were big hits, were cheap to do, and reasonably safe to pull off in the classroom.

The Pencil Holder – Introduction to Drill Press

The pencil holder is simple. Start with a 4″x4″ fence post, chop into square 4″x4″x4″ chunks, and let students drive holes to fit pencils. I used an 8′ piece of douglas fir from the big box shop that cost me around 10 bucks. That’ll make 24 pencil holders at a cost of about 40 cents a piece.  I let the students mark out the center points for their holes, and let them at it.

The Tea Candle Holder – Introduction to the Miter / Hand Saw

The tea candle holder was a simple project. Start with a 2×4, cut it down to about a 12″ section, and drive 3 holes for tea candles using a spade bit. We rounded our corners using the belt/disc sander, and one student split the 12″ section into 3 separate pieces. She even finished with contrasting dark danish oil and boiled linseed oil. It turned out amazing!

Simple Cutting Board – Introduction to the Bandsaw

The last simple project was a cutting board. I picked up a 6′ length of 7″x3/4″ poplar board from the big box store, and split them into cutting board blanks that were around 10″ long. The challenge was to sketch out a simple design to give the board some character, cut it on the bandsaw, and put down a coat of mineral oil. This was super simple, and super rewarding.

The Finishes

I wanted the students to experience the challenge and joy of finishing their projects. That meant lots of hand sanding (foam sanding blocks are worth the investment!), and hand rubbed oil finishes. I had a small selection to choose from, a danish oil, boiled linseed oil, tung oil finish and a wipe on poly. This final step in each of the projects too the experience above and beyond and the students had a blast.

Woodworking doesn’t need to start off with complex joinery, or fancy hardwoods. Some of the best projects take just a few cuts, a few holes and a coat of finish. The students had a blast learning about the tools, and were all extremely proud to walk out with all of their projects.

# Creating algorithmic designs for fabrication in Beetleblocks

I was recently tasked with creating a quick activity that could be done within a booth at the Philadelphia Science Carnival, something that would take only a few minutes to do so kids could filter in and out of the booth. It was going to be tough to do something great with that sort of timeline, and nearly impossible to stock enough supplies to support the 400+ kids that will come through during the carnival. I decided to tap my favorite ‘free’ supply, adhesive vinyl scraps from the sign shop, creating stickers on our craft plotter.

Now stickers resonate with kids in a way I don’t really understand, so I knew it would be a good draw at an event like this, but I wanted to do something less frivolous than just making worthless stickers with a craft cutting machine. So, I turned to code. We could program a cool design, and cut that out. I dove into Beetleblocks and came up with a really simple bit of code that quickly demonstrated the power of code, and the magic of math.

The code is fairly simple. First we can have students create a square, realizing that we can use the repeat block to make our lives easier. The result is this simple little chunk of code that produces a square.

Great! We have a square…but that is a pretty boring shape. Maybe we can make it interesting. Now we can start to think about some math. We know that a square is a 4 sided shape, with 90 degree angles in each corner. If we multiple the amount of sides and the angle of the corners, we get an important number: 360 degrees. What if we wanted an 8 sided shape? What would be the angles of the corners?

Great! Now we’ve learned something important, and we can really get creative with the initial shape that we draw…but a single shape is boring. Lets now create lots of these shapes, and rotate the origin of the shape a bit each time to make something a bit more interesting.

Now we’ve got something interesting! But look, we can make another interesting observation in this code. We are drawing 6 shapes within the repeat block here….each time rotating by 60 degrees. 6*60 again gives us that magic number 360! So we can create more shapes, and as long as the product of the degrees of rotation and the number of shapes equals 360 degrees.

Now that we have this code set up, we can let students play around with the numbers.

What happens if we have a 360 sided shape with 1 degree angles?
What happens if we nest yet another repeat block?
Can we use operators to automate the math for us?
Can we write our own functions like drawShape or repeatShape?

There are lots of questions that can drive further exploration. In the end, we might clean up our code using custom blocks, or add some math and variables to automate things for us.

A quick tip of note; to make the lines easier to see, we can change the display port settings in Beetleblocks. Uncheck the grid and the axis and check off ‘Parallel Projection’ to see directly down on our shapes. You can change the color of the background under the settings ‘gear’ icon, and change the color of the line with the ‘set hue to’ block under colors. You may need to zoom to fit as students start to build bigger shapes with more sides as well.

Now, the problem with this lesson is turning these thin lines into something that can be cut out into stickers, or on a laser cutter, etc. It is easy to cut these lines, simply exporting the .SVG file out of Beetleblocks. The hard part is giving those line thickness enough to create a defined shape. The easiest way I have found is importing the SVGs into Inkscape, giving the path a fairly thick stroke, and using the Stroke to Path tool.

Ultimately, this simple activity can show a great deal of coding concepts quickly. Loops, operators, variable and functions can all be explored. The connection to geometry is obvious, using degrees in an applied way can help solidify how degrees and periodic functions can be used in action.

I’d love to build on this concept to do things like laser cut jewelry, hand coded letters to create signs, continue to drive algebraic math connections while creating complex machinable 2D designs. With the focus on 3D design and 3D printing, the power of 2D line is sometime forgotten.

# Introducing Design with Vexillology

As I planned to introduce some elements of design to my new 6th grade group, I turned to my personal guide through the world of design, Roman Mars and 99 Percent Invisible. The stories in their podcast are always captivating, and eye opening about all of the tiny designed elements that make up our world. I knew I’d find a good story there to share with my students…however 6th graders don’t have the attention span to listen to a 20 minute podcast…neither do I really some days. So I turned to Roman Mars’ Ted talk on the design of flags. In it, he lays out his hatred of poorly designed local city and municipal flags. He doesn’t just complain though, he offers a solution in the form of a set of flag design rules laid out by the North American Vexillological Association.

These design rules are simple, and clear:

1. Keep it simple: The flag should be simple enough that a child can draw it from memory.
2. Use meaningful symbolism: The flags images, colors, or patterns should relate to what it symbolizes.
3. Use 2-3 basic colors: Limit the number of colors to three, which contrast well and come from the standard color set.
4. No lettering or seals: Never use writing of any kind or an organizations seal.
5. Be distinctive or be related: Avoiding duplicating other flags, but use similarities to show connections.

These simple rules are quick, and easy to introduce to a group of students. In fact they are all described in great detail with examples in ‘Good Flag, Bad Flag‘, a 15 page primer in flag design published by NAVA. This provides a really great framework for a quick and easy design lesson: Design a flag for your school, classroom, neighborhood, etc.

So I did this quick lesson with a group of my 6th graders. I wanted to have them experience the practice of using a design rules to develop a unique flag for either the school, or the city of Philadelphia, which itself is in need of a new flag.

Building from the Ted Talk, I encouraged (but did not require) that students draw the flag on a 1″x1.5″ square cut from a notecard. As noted by Ted Kaye in the Roman Mars Ted talk, that is the size a flag appears when seen from a typical distance. There were lots of ideas, lots of great flags, and a few that failed to listen to many of the design rules, but the gears were turning and the conversations were happening. What is the best symbolism to represent our school? If we threw away our blue and grey colors and had to pick our own colors, what would you choose?

My effort with teaching design is to have my students look at the world in a different way. Roman Mars and I have the same mission in this sense:

“My mission is to get people to engage with the design that they care about so they begin to pay attention to all forms of design. When you decode the world with design intent in mind, the world becomes kind of magical. Instead of seeing the broken things, you see all the little bits of genius that anonymous designers have sweated over to make our lives better. And that’s essentially the definition of design: making life better and providing joy”
– Roman Mars

The level with which the students connected to this lesson was pretty shocking. I was expected a bit of ‘this is stupid and boring’, but after breaking down what makes a good flag, and what makes a bad flag, we had a blast digging through different flag designs and showing off the best and worst we could find.

This project can easily to be extended in the makerspace classroom, using tools like the vinyl cutter to cut stickers that my students love to put on their computers, or to cut fabric that can be stitched together into a full scale flag.

It was a quick and easy lesson, and surely all of my students will now never look at a flag the same ever again. In fact, they might be critical of all of the terribly designed flags in the world, and perhaps do something about it.

I’ve prepared a slideshow of good flags and bad flags to show to students, or to use to quiz them after reviewing the design rules. See that here. Or, if you like to Kahoot in your classroom, I’ve put together this Kahoot too.

# 3D Printing Rockets

Recently, I was given the chance to run a series of all day projects with some of my students. This gave us all day to focus on big projects, start to finish. Following the theme of ‘Aerial Explorations’, we took to the sky to explore flight.

Perhaps the most interesting project to come out of these experiments was the 3D printed model rockets. The idea was simple…print basic rockets that would accept a small model rocket engine, and see if they’d fly. I took inspiration from the ‘disposable rocket‘ by Thingiverse user kebes22. I was worried that this minimal two piece design was the consequence that the small engines couldn’t launch solid plastic rockets. Presumably the off the shelf rockets are made of thin cardboard for a reason…

However, after some back-of-the-napkin calculations, I decided that the rockets would launch just fine. Likely the additional mass would act pretty significantly against the thrust, but we weren’t attempting to go into orbit, simply trying to take flight!

We turned to Tinkercad as our design tool of choice. This was mostly because my students had the greatest experience with it. If I were using this project to introduce students to 3D design and printing, I likely would have used 123D Design instead. 123D Design has features that make designing with specific dimensions much easier. And, the cylindrical model of a rocket lends this to a perfect example case for the revolve tool, that is often times a bit confusing to students new to CAD.

We used 1/2A3-4T rocket engines from Estes (who has some great teacher resources), from Amazon in a bulk pack. Using the 13mm dimension for the diameter, we left a cavity in our design to accept the rocket engines. In Tinkercad, I instructed students to make a cylinder with the same dimensions of the engine, then had them define it as a hole and instructed them to make sure to place the component in the center of the rocket. Students also design ringlets for the launch pad guide rod to connect to. However, in the long term, adding the guide after the print would be easier. Perhaps as simple as a drinking straw, or even a stirring straw from the breakroom would work better.

The instructions were very limited, as I wanted to allow the students to be creative with this project. However, any level of aerodynamics, or rocketry lessons would be easy to attach. The lesson can even be expanded to attach to Kerbal Space Program and KerbalEdu for interactive video game based simulations. (I found the demo of Kerbal Space Program supplied plenty of content for our one day lesson.)

Finally, we printed the rockets on the Printrbot Simple Metal. The prints took no more then 30 mins each printing at 0.25mm layers at 65mm/sec speed. The prints weren’t beautiful at that speed and resolution, but they were functional!

The launches were all successful! They all took off to a height of around 100-150′ before returning to earth. For safety, I kept all students a good 50′ from the pad unless they were at the pad launching their rocket. I connected the leads to the engine, then gave the nod to the rocketeer, stood back and allowed them to launch. Launching at a sleight angle downwind ensured no rockets returned back onto anyone’s head.

# Reading Milliohm Resistances With The Arduino

I’ve recently been attempting to read milliohm resistance with the Arduino, and I’ve found out it isn’t terribly easy. The main cause is that the Atmega chips 10bit ADC doesn’t provide the resolution needed. As a result, I’ve been hunting for a different method, and I have come up with what I think is the best solution.

Using four-terminal sensing, or kelvin resistance measurements, we will use a constant current supply and some Ohm’s Law-Fu to read a voltage that is proportional to the resistance.

Lets start with some theory, and Ohm’s Law. First off, we are going to be looking for resistance, so lets put Ohm’s Law in terms or resistance:

$r= frac{v}{i}$

Now we know that we need voltage and current to determine the resistance. So, we’ll need to build a current supply, with a constant output. For example, if we generate a constant 1 amp current, than we will have a handy relationship:

$r= frac{v}{1} = v$

Given a 1 amp source, we are given that resistance is 1:1 proportional to the voltage.

Lets take a look at a circuit.

This circuit is our constant current supply. Using the LM-317, and a resistor between the adjust pin, and the voltage out pin, we create a basic constant current supply. Using a 120 ohm resistor, we will be generating a 1amp current. However, when we use Arduino, we have the power to do some calculations, we we are going to scale the current down by a factor of 10, and replace the 120 ohm resistor with 12 ohm resistor, resulting in a current of 100mA, or 0.1amps.

With our constant current supply, the next step is to measure the voltage across the resistor we want to measure.

Now we have our constant current supply powered by the Arduino, supplying 100mA across our resistor. We are going to run from the resistor, to the A0 pin on the Arduino, and the other side to ground. Any low ohm resistor can be put in place of the 12ohm resistor, just keep in mind that you’ll have the read the resulting current with a multimeter, than enter that value into the code. In my example, I built with a 10ohm resistor, that resulted in ~125mA, so my code uses 0.125 as my current.

Lets go ahead and throw some code onto the Arduino, and try to read the voltage, do some math to generate the resistance, and read it out!

``````const float currentSupply = 0.125; // The current generated by the LM317 and 10ohm Resistor
const float referenceVolts = 5;        // the default reference on a 5-volt board
const float resistorFactor = 1023; //Full scale this time.
const int resistancePin = 0;         //Resistor / output from 317 circuit connected to analog pin 0
void setup()
{
Serial.begin(9600);
}

void loop()
{