Designed, Built, Flown!

You can't choose the hand you're dealt, but you can play it to win every time.

Along with every one else around the globe, the Providence Engineering Academy was dealt a tough hand in March. Having worked so hard in the lead-up to the major capstone project—to design, build, and fly a powered tethered aircraft—being asked to complete the project from home was not the situation that anyone wanted. But in the spirit of problem-solving, our junior and senior engineers faced up to the challenge. After all, what is engineering all about if not solving problems?

Our last post on this project ended with the four teams designing various aircraft components using professional-grade CAD software. They had sent their designs to Mr. Meadth, who began to 3D print their fuselages and tails, cut their carbon fiber, and CNC mill their wooden wing ribs, all from the comfort (?) of his garage.

The garage workshop: where the magic happens!

Over the course of several weeks, each team's delivery bag in the garage began to pile higher and higher with these manufactured components, along with advanced electric motors, lightweight lithium batteries, tissue paper, and other bits and pieces. Every last one of these components had been accounted for in duplicate: in a virtual CAD model and a complex spreadsheet. The CAD model held the actual design for manufacture, visualization, assembly guarantee, and mass/center-of-gravity prediction. The spreadsheet calculated wing and tail lift, which in turn yielded a force and moment balance, and also a redundant center-of-gravity prediction. (Redundancy is not a negative word in aircraft engineering!)

Quick science lesson: the center of gravity (c.g.) is where the sum of all weight is located. In other words, it's the point at which you could balance the aircraft on your finger, or where you could hang it from a string. It is determined by the masses and locations of the individual components, and it was critical that our uncontrolled aircraft had the center of gravity forward of the wing's lift force. Without going into the deeper explanation, having the center of gravity as close to the nose as possible means that the aircraft will be self-correcting and stable as it flies. Try attaching a paperclip to the nose of your next paper aircraft and note the dramatic improvement! This is why we ran two separate c.g. calculations using two different method—we wanted to absolutely confirm before manufacture.

Fresh off the printer, ready for delivery!

Sam and Josh work on RUBYGEM, papering and
doping the wings

Mr. Meadth delivered each team's bag directly to their respective homes. Upon arrival, each team worked hard to assemble the aircraft. This involved inserting carbon fiber spars into 3D printed wing boxes, stringing the wooden ribs evenly along the spars, covering the ribs with tissue paper, and then applying dope (a kind of water-based glue) to the paper. The doped paper dries and hardens into a kind of thin shell. The various electronics components were also connected and secured, along with the tail and undercarriage (landing gear).

At the same time, the simple tethering system had to be designed and implemented. The wooden stand sits in the middle of the flight path, and a 3D printed bearing served as an anchor point for the tether line. The tether was then attached to the wingtip. Some of the aircraft needed a little more rigging to ensure that the centripetal force didn't rip the wingtip loose!

Fast forward to the big day. Mr. Meadth made a final decision to hold the test flights in the gym, instead of outside. The smooth floor would take one more variable out of the equation, and the enclosed space would keep out any stray gusts. When your plane only weighs about 2 pounds and floats on the breeze, a gentle wind can be your worst enemy!

Thanos steps on to the court!

First up to the plate was Nolan and Pedro. Their purple and grey monoplane had a planned weight of 800 grams (less than a liter of water). The wingspan was a fairly standard 1.06 meters (a bit more than 3 ft), with a conventional tail style and taildragger undercarriage. Mr. Meadth tied their aircraft to the tether as the excitement mounted, and Pedro took the first turn at the controls. A gentle increase on the electronic throttle, and the affectionately named Thanos rose up beautifully into the air! Nolan took a turn as well, and the team scored two successful take-offs and two successful landings—the ideal outcome!

Plan view of Thanos, taken from the CAD model

Next up was Madison and Alena. Their Airplane Baby was ready to take its first steps, with Alena at the helm. In various shades of baby blue, the 540 gram winged wonder stretched out at an impressive 1.2 meter span (about 4 ft). Their wing aspect ratio (the ratio of wingspan to chord length) was a very healthy 12, almost double that of some other teams. But would it fly?

Airplane Baby gets ready to roll!

The girls produced a set of plans for their
written report

Without a doubt! Both Madison and Alena toured the gym in a somewhat rollercoaster fashion, the tether line being stretched to its limit. We estimated just a couple of feet clearance between the aircraft and the walls—enough to make any pilot sweat a little! But after a safe landing, all was well.

And now a little math. Replaying the video, it looks like Airplane Baby took about 3.5 seconds to complete a lap. If the diameter of the circle was about equal to that of the basketball court (50 ft), then the radius of the circle was half that: 25 ft. The speed of the aircraft through the air is equal to distance over time; the circumference of the circle divided by the time to get around that circle.

Circumference = 2π × radius = 157 ft

Speed = distance/time = 157/3.5 = 45 ft/s

This was about 36% faster than their design speed of 33 ft/s, which only goes to show that their stable aircraft design works just as well under a variety of situations. (It may also mean that their wings weren't as effective at generating lift as theorized!)

Sam and Joshua took to the floor after that, with a slender red aircraft tied to the tether: RUBYGEM. With a planned mass of 440 grams (almost exactly one pound), this was the lightest plane on display. Their rectangular wing planform spanned 1.08 meters, and they planned to fly at only 8 meters per second (26 ft/s). A lighter aircraft does not need as much lift to stay in the air, and so for any given wing design, it can fly slower and still generate the force it needs.

RUBYGEM steps out in style

As RUBYGEM gracefully lifted into the air, it was obvious that she indeed favored a slower style of things. Completing each lap in almost 5 seconds, the flight speed can be calculated at 33 ft/s. This is also faster than their design speed, which reinforces the theory that perhaps there is more inefficiency in the design than our theory accounts for. Sounds like real life, all right!

After successful landings, Mr. Meadth made the decision to head outside with the fourth aircraft: Big Wing Boy. And boy, was it big! At over 2 meters (6.5 ft) span, this multi-colored monoplane was just too big to spread its wings indoors. It was also designed to fly a little slower, and was very light for its size: 800 grams.

Big Wing Boy, taken from the design report

There was, however, one significant issue: while the design looked good in the CAD model and spreadsheet, the greater spans and sizes meant the physical attachment of the parts was just that much more difficult. The sheer size tended to stress the wing root joints more, so extra tension lines were strung between wingtips to help hold everything together.

Being outdoors on the grassy field, the decision was also made to give the aircraft a running hand-held start, because the wheels get caught in the grass. Risky? Yes! Mr. Meadth held Big Wing Boy aloft and kicked off his shoes to get the best launch speed possible. Given that an Olympic runner travels at around the 10 m/s mark, finding the necessary design speed of 8 m/s would be a challenge!

Ben cranked the throttle to a healthy roar, and Mr. Meadth began to dash around the circle. With a final push into the air, B.W.B. lifted up into the great blue yonder where he belonged. All seemed well... and then the unthinkable! Video footage analysis confirms that the carbon fiber stick connecting the wings to the tail tore loose from the aerodynamic loads, and no plane can ever do well without that stabilizing influence. This principle was, in fact, one of the central pillars of the second semester!

The moment of horror as the tail comes loose!

The aircraft wanted to perform, but just couldn't remain aloft. It plowed into the grassy field after only a few seconds of genuine flight. A quick repair and a repeat attempt was launched shortly thereafter, but another half-lap was achieved with similar results—with more permanent destruction this time! There was no third flight.

At the end of the day, what did we learn?

1. Challenges are there to be overcome. The project could have modified to be easier, simpler, more virtual, you name it. But that kind of logic doesn't get you into the history books, and doesn't give the same kind of satisfaction. Greater levels of determination can turn challenges into victory.
2. Theory is useful, but doesn't account for everything. Math and physics equations and computer simulations are incredibly useful, and with high-level manufacturing can be a very good analogy of the intended outcome. But the fact is that our theoretical calculations didn't account for a great many factors. This makes it all the more important to create robust, stable designs. The aircraft didn't perform exactly as intended, but they did perform in the real world.
3. Aircraft need firmly attached tails. You may want to check the welds next time you hop on board your next 737.

Congratulations to our eight aircraft engineers, and many blessings on the four seniors, now alumni: Ben, Todd, Alena, and Madison. You have completed something to be proud of!

Design, Build, Fly!

Our students can't be together in person right now, but nothing is going to stop them finishing the capstone design/build/fly project for the 2019-2020 year. With digital tools in their hands and computer-controlled manufacturing equipment at the other end, our budding engineers, now sheltered in place, are experiencing the reality of a modern workflow. Even before the advent of COVID-19, many companies routinely collaborated from around the globe, producing advanced designs using international teams. Although not our first choice of preference, we're taking the challenge head-on!

Mr. Meadth teaching aircraft stability via Zoom

The first step for our skillful students was to learn the ins and outs of classic aerodynamics. In January, February, and March, the eight juniors and seniors studied airfoil behavior, lift and drag equations, and learned how to use weighted averages to find the center of gravity of a complex system. Our team learned the different parameters of airfoil design, and used virtual wind tunnel tests to predict just how those airfoils would respond in real life.

The virtual wind tunnel program XFoil: a classic
historical aerospace simulation! Note the cambered
airfoil shape at the bottom, with the yellow boundary
layer on top and the blue one below

Even more important was the notion of stability. What makes some physical systems stable, and others unstable? The incredible hexacopter drone that emerged in the first semester was inherently unstable, which means that it will rapidly flip and roll and fall out of the sky if the onboard computer-controlled gyroscopes were to stop doing their job. The gyroscopes sample the position and orientation of the drone dozens of times per second, and send minor corrections to the six motors, all without the pilot on the ground ever knowing it. Stable drone flight is an astounding human accomplishment, powered by calculus and implemented by technology, but it is not inherently physically stable.

On the other hand, the powered fixed-wing aircraft in this project must be physically stable. Tethered to a central post and flying continual circles, the aircraft will have only one remote-control channel controlling the power to the motor. There are no ailerons, elevators, rudder, or flaps. Without moveable control surfaces, the aircraft must be designed to constantly self-correct all by itself. If the nose dips down a little because of a gust of wind, it must automatically seek to find level again. If it rolls a little too much to one side, it needs to roll back again. The principles involved hold true for most common vehicles: cars, bicycles, even the caster wheels on supermarket carts.

Having mastered the physics involved, the students set about the difficult task of starting their design. No kits, no instructions, no fixed starting point! In teams of two, the students created a complicated spreadsheet filled with graphs and tables and physics equations, listing masses and locations and forces and moments. The students also designed a multi-part CAD model according to those numbers using the professional-grade online platform Onshape; ideally, the CAD model, the spreadsheet design, and the manufactured plane itself will end up as three matching representations of the same reality.

Pedro's and Nolan's aircraft in its complete form

The same aircraft in an exploded view

Mr. Meadth ordered in the necessary tools and materials for construction: carbon fiber bars and tubes, balsa wood, lithium-ion batteries, electronic speed controllers for the advanced motors, propellers, wheels, and filament for the 3D printer. These materials were fully paid for by a generous grant from AIAA, the American Institute of Aeronautics and Astronautics. AIAA believes strongly in encouraging the work done by K-12 schools in advancing aerospace education, and Providence School has received similar grants in the past.

The delivery of the critical
components arrives!

Through the COVID-19 distance learning experience, the four teams produced their designs without ever meeting in person with each other or the teacher. Because of Zoom lessons, shared spreadsheets, and the powerful collaborative nature of Onshape, this project didn't skip a beat. Mr. Meadth set up a manufacturing station in his own garage, and busily set to work producing what the students had designed. The CNC (computer numerical control) machine carved out flat balsawood ribs with exact length, thickness and camber dimensions, and the Raise3D 3D printer produced the three-dimensional components such as fuselages and tail.

The Providence Engineering Academy
manufacturing facility!

A completed wing rib from Ben and Todd, with
carbon fiber spar inserted

The vertical tail for Nolan's and Pedro's aircraft,
over nine hours in the making!

The huge 30-hour print of the fuselage/
wing box (lots of temporary support
material can still be seen

Ready for clean-up, delivery, and assembly! The
motor and one propeller option are in the background

Where to from here? The Advanced Engineering II students will receive deliveries of their manufactured pieces, to be assembled at home. Test flights, possible redesigns, and the final maiden voyages are scheduled to happen in late May—stay posted for the culmination of this exciting story!

Major Project: Hexacopter Drone

(The fifth in our student blog series, written by Sam in 11th Grade, is followed by the teacher's two updates on the project, so please read all the way down! Flight tests were finally successful, as students and teacher alike learned the hard realities of "going back to the drawing board!")

While we don’t plan on taking him to the sun, Icarus was the name we selected for our massive hexacopter drone. With a 31-inch diameter, and the theoretical ability to lift almost two pounds on top of its own five-pound weight, it is operating at the higher end of recreational drone constraints. Most commercially available drones today feature only four propellers, and a mass of around one pound.

Early sketches of the design, with design priorities listed on the side

When we were designing “Thiccarus” we decided to push the boundaries with the materials we had available. A hexacopter design, as opposed to a more common quadcopter (a standard recreational design with four propellers), gave us more lift power and stability with a trade off on speed and maneuverability. To reduce weight and maintain strength Thiccarus would be constructed with 3D printed body parts and carbon fiber struts connecting them. However, when we were brainstorming, we decided that our drone’s primary function would be cargo delivery (despite my suggestions to make it into a fishing drone or a laser-toting drone with a search and destroy mission).

Pedro, Nolan, and Joshua tear apart
old quadcopter drones from two years
ago--fare thee well!

We came up with our design, then our constraints and requirements. After this, we split into design teams, each headed by ”captains.” After the protective shrouds around each propeller and control center base were decided upon, we set to starting a joint Onshape project. Onshape is our 3D design platform of choice for this project. Each team member was assigned one component of Thiccarus to design, and it came together well in a collaborative fashion. Each member of the design team is able to see in real time how their part will integrate with the other parts, which is incredibly helpful.

The eight students work concurrently on the drone CAD model,
with each one instantly able to see how their component fits into
the broader scope

The hexacopter design emerges!

The largest and most difficult piece to print: the central electronics
platform; five or six attempts at printing were required

Icarus is currently in the printing stage, and when it is fully constructed, it will be mounted with two cameras feeding to a battery powered LCD screen. Steered by the controller, it will be capable of flying high and low to deliver small payloads.

(Sam's article was written in early October. After a delay in printing production due to some technical difficulties, the entire drone was finally fully assembled and taken for some early test flights. And now the update—which gets a little technical...)

After many hours of printing and assembly...

Sam, Ben, and Todd carefully attach
the motors and batteries and other
electronic components

The 8th Period engineering class proudly marched their huge drone out to the Providence soccer pitch. Gentle (and safe!) power-ups in the classroom had proved troublesome, with erratic behavior being immediately apparent. The drone was very touchy, and tended to spin around and roll to one side. Cutting the throttle from even six inches of altitude caused the aircraft to fall with a ungraceful "thump", with small 3D-printed pieces occasionally breaking off.

Alena gave an insightful suggestion that we could take it outside and stretch out a big sheet of fabric to catch the drone as it fell. This would allow us to try to gain more altitude—and more time to evaluate its behavior and get it under manual control. The soft fall into the fabric would certainly keep both drone and students completely safe! As an added bonus, we would look comically like cartoon fire-fighters.

The group heads outside to try an initial flight: safety goggles on!

And look like cartoon fire-fighters we did! The plan worked rather well, except for Ben slipping accidentally in a mud patch on the field in his zeal for saving the drone. With the extra flight altitude and time, we learned that the machine wanted to spin on its vertical axis—absolutely out of control. Where it should have lifted gingerly into the air and hovered obediently, it was a veritable whirling dervish, and the group could not even agree on their recollection of whether it had spun clockwise or counter-clockwise!

It may look like the class is flinging it into the air—we promise
it is actually flying!

In a typical situation like this, the pilot should be able to add in some "yaw" trim. This means that the controller is set to always provide a little bit extra of yaw control, intended to counteract whatever is naturally happening and make everything balance out again. But adding yaw trim in either direction just didn't change anything, and after one particularly wild spin the drone fell outside of the fabric and broke one of its 3D-printed propeller shrouds.

See that tilt to one side? About three seconds later Thiccarus
successfully escaped our circle of friendship!

Back to the drawing board...

1. It is possible that the flight controller—the 1-inch small box that houses gyroscopes and inputs and outputs and magnetometers and so on—is just misbehaving or badly calibrated. But after several recalibrations and trying an alternate one that we had in stock, there was no improvement. Check.
2. Is Thiccarus just way too "thicc"? Maybe. We could have designed more aggressively, and perhaps brought him down to 2 kg even (4.4 lb). But the specs say that each motor should be able to create up to 550 grams of thrust. With six motors in total, that's 3.3 kg of thrust available (7.3 lb). And it's definitely getting off the ground, even with the thrust output turned down for safety. So: check.
3. It is possible that one or more motors are just misbehaving or getting bad signals. Tiny, threadlike wires carry the commands between the different components, and we have run into problems of this nature before. But replacing one bad cable fixed that, and simple individual motor bench tests show snappy, responsive motors that will blow your papers away from across the room.

When all else fails, Google it. Apparently, when your drone experiences untrimmable yaw, it is likely the result of not having set all motors perfectly level. In other words, one or more propellers might not be perfectly flat relative to the ground, but tilted slightly to one side. And yes, this is quite noticeable on poor old Thiccarus once you look for it. Fortunately, it can be easily solved by readjusting the four screws that hold each motor down, and putting a little "shim" on one side to nudge it up to level.

This is actually an interesting application of standard high school trigonometry. If a thrust vector is pointing straight up to sky, well and good. This is what the flight controller is banking on for its power distribution calculations. But if a motor is tipped to one side by even two or three degrees (barely perceptible to the eye), the aircraft will experience a mysterious lateral force equal to the thrust times the sine of the angle. If the motor is generating a healthy 500 grams of thrust (a little over a pound), three degrees of tilt creates 26 grams of sideways thrust (500sin3°). Small but significant—and the flight controller is not accounting for it.

Maddening: yes. Fixable: absolutely. The motors will be checked and adjusted, and Thiccarus will be bandaged up and flown again. It is also very likely that a Mark II design will surface in the second semester, with higher tolerances for motor angles accounted for from the very beginning and a lighter airframe. Less airframe weight means longer flight times, a more responsive drone, and a greater possible payload.

Providence Engineering Academy: carry on!

(Our final update for this story on the 19th of November.  Spoiler alert: it's a happy ending!)

As promised, the motors were checked and adjusted. Ben and Mr. Meadth stayed after school and carefully placed pieces of card under this or that side of the motors to shim them up, bringing them as close as possible to vertical. Three motors were in need of adjustment, but none of them were out of line by more than about two or three degrees.

The drone was powered up, with high hopes... but the end result was exactly the same. Thiccarus wanted to flip over to the side and rotate faster and faster, and nothing could persuade him otherwise. Forget flying too close to the sun—Thiccarus couldn't even get off the ground!

And then...

And then...

Mr. Meadth had his flash of inspiration, and it all came down to this image:

The source of all problems.

This diagram shows the initial wiring and setup instructions from the flight controller. A certain teacher thought he had carefully followed the diagram; unfortunately, he had set the actual propeller directions all opposite. For example, propeller 1 was supposed to be rotating clockwise, but it had been set up to be counter-clockwise.

What's the big deal, you ask? Well, while having everything opposite would still be balanced to some degree, the flight controller uses the spinning propellers to control its yaw. Say the craft wants to yaw to the left, it chooses a propeller to spin faster to the right (like propeller 1), and Newton's Law of Reactions takes over. If it wants to yaw to the right, it might choose a left-spinning propeller to do that (like propeller 2). But since each and every one was backwards, the corrective actions it tried to take were in every case making the situation worse. If it started drifting left, it would end up spinning more left—a classic vicious circle if ever there was one.

A quick click of a checkbox in the computer and that was solved. All propellers: backwards. Oops.

Propellers... spinning the correct way!

You know you're doing something
right when you're looking at the bottom
of the drone

This portable outdoor screen receives
video input from two onboard cameras

Today marks another successful series of flights. We currently get about ten minutes of air time with two fully charged batteries. Three students plus teacher have been brave enough to fly around a little bit. No major accidents—perhaps a leg snapping off here or there with a rough landing!

Lessons learned:

1. Persistence pays off. If this is a thing that can be done, then you can do it. Just get out there and keep troubleshooting until you work it out.
2. This is a new era of high school education. To collaborate on a CAD model, 3D print it, order the electronics, and create a hovering 2.2 kg monstrosity in the space of three months is just not something a school could have done in-house ten years ago. Truly these are amazing times!
3. These students are capable. With the right leadership and direction, they know how to think and problem solve and calculate and design. They will go far.

The story ends here, but keep an eye out for Mark II! We just can't resist. There are already so many things that could be optimized (chiefly, stronger airframe and lighter weight). Lighter weight means more air time, so bring it on! Look out for Son of Thiccarus in the second semester, and until then, stay posted.

Summer Camp 2019

This summer, the Providence Engineering Academy once again hosted the very special Robot City summer camp. With assistance from four capable high school engineering students (Alena, Davis, Pedro, and Zach), Mr. Eves and Mr. Meadth put on an unforgettable experience!

(Please note that all photos in this article have been selected to avoid showing camper faces, since not all students are from Providence with a photo release. Apologies if you're looking for your loved one's smiling face!)

Day 1: Architecture
After breaking into four teams, each group selected the theme for their quadrant of Robot City. The Green Team chose Time Travel, the Blue Team settled on a Medieval Castle, the Yellow Team laid out an Alien Attack on the Beach, and Red Team was Future City. A quick lesson of folding geometric nets, and all campers from 3rd to 7th Grade were ready to build!

The skyline emerges! A colorful mess of card and tape!

Red Team's skyscraper went up and up and up, and needed to be
tied down with guy ropes!

Blue Team's "Nice No-Trap Castle". Should we believe them?

With inspiring challenges like "Tallest Tower" and "Most Colorful", each team worked hard to lay out their cities. Skyscrapers rose up six feet into the air, zip lines were strung out, and spaces carefully divided out.

Day 2: CAD and 3D Printing
It might sound complex, but physically printing CAD (computer-aided design) models is something within the reach of any elementary student! Mr. Meadth taught the campers how to use Tinkercad, a free in-browser design tool created by AutoDesk. Designers can use simple shapes such as cylinders, cones, spheres, and prisms to create more complex models, such as houses and rocketships and characters.

Two of our campers work on their CAD models (Owen's model
on the right is shown in detail below)

This is a great tool to get kids thinking in terms of linear dimensions, negative and positive space, perspective, volume, and it's just plain creative fun! Here are a couple of examples of what the kids came up with. We also had spaceships, tanks, flying cars, and castles. Wow!



Once created (the models above took the students less than an hour to build), the designs were sent to the 3D printer. At a small enough print size, most models were done in about an hour, in a range of colors. Of course, after the camp the students got to keep whatever they have printed!

It's just as addictive as watching TV, but at the end of the program
there's actually something to show for. Thanks, Raise3D!

Day 3: Electrification
Always a favorite! Mr. Meadth gave a quick lesson on simple circuits, explaining terms such as "LED", "voltage", "series", and "parallel". Each team was given a supply of copper tape, coin batteries, and LEDs, and shown how to connect them together to power their city. It wasn't long before the entire room was lit up with red, blue, orange, white, and green!

A lovely beach paradise in the shadow of the skyscrapers
(the tidal wave was added later)

The Green Team's time travel zone included some helpful signs
(because time travel can be confusing)

A scale replica of the Golden Gate Bridge, courtesy of Abigail

All teams took up the extra challenges as well, building working paper switches, including both series and parallel circuits, and working to match their lighting arrangements to their theme. Blue Team created "laser traps" for their medieval castle, and Green Team strung out a long neatly-lit road to mark out their different time travel zones. Billboard were illuminated and "stained-glass" windows lit from the inside.

Mr. Eves works on the Blue Team's medieval quadrant

LEDs don't come through well in photos, but you get the idea!

When parents arrived for pickup on Wednesday, the lights went out, and the party started!

Day 4: LEGO Robotics
What's a Robot City without robots? This year, Mr. Meadth and Mr. Eves guided the campers on how to incorporate LEGO Mindstorms robotics sets. Rather than creating robotic systems that would move around (and potentially destroy delicate buildings and circuits!), the teams focused on stationary mechanical systems. Mr. Meadth gave some lessons on essential mechanical systems (bevelled gears, gear reductions, universal joints, cams and cranks, etc.), issued some fun challenges, and away they all went!

Does this look like anybody's bedroom floor? Times it by 16.

A futuristic monorail glides around Green Team's city buildings

What's a medieval world without an authentic, functional windmill?

We were blown away by all of the amazing creations that campers and their team leaders built: several working elevators (with tracks and with pulleys/windlasses); a slowly rotating time travel portal (sadly not actually functional); a crank-powered shooting spaceship; an amusement park ride; drawbridges; a merry-go-round; several demolition machines!

(P.S. For any parents of elementary students wanting a more cost-friendly version of LEGO Mindstorms, I highly recommend LEGO Boost. At about $150, it is a somewhat simplified system, still with sensors, motors, and fully programmable using a block-based system. The only downside is that it does always need a tablet/phone/computer app to be running via Bluetooth to make it work.)

Day 5: Do Over
At this point in the camp, the kids have learned so many different things and have typically gravitated towards one or the other. Some of them think that LED illumination is the coolest thing, and others just can't get enough of making CAD models online. So on the fifth day, Mr. Meadth and Mr. Eves issued a few more challenges of various sorts. The teams helped put together a welcome sign with their photo on it; they all constructed a wearable accessory lit up with more lights and batteries. Some made hats and funky glasses and others made glowing swords!

The fun keeps coming on Day 5!

Robot City continued to grow in complexity and variety. Some teams incorporated sensors into their robotic systems, using touch triggers and infrared detectors to more accurately control their elevators and bridges.

By the time parents arrived at 12:30, the teams were ready for the final wrap-up. All points were tallied, and the all-girl Green Team took the grand prize, much to their delight!

Parents were delighted to see everything
the kids had accomplished... and that
someone else was handling the cleanup!

Mr. Meadth and Mr. Eves would like to thank all families for making our third Robot City camp such a success! We intend to run this again in 2020 (new ideas are already in the works!), so please spread the word amongst family and friends. You can start by sharing this article with someone who might be interested! And remember, this camp is open to all students, not just those from Providence. We're always glad to welcome new friends from outside our regular community.

Until next year, may these junior engineers keep on designing and keep on building!