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Grand Prix: a STEAM Challenge Involving Design, Mechanics, Coding and Fun!

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(I'm participating in the "Classroom Science Contest" of Instructables. If you like my project, your vote will be highly appreciated!)

Hello. My name is Mario and I am a Colombian STEAM teacher in Azerbaijan.

My education center organized a Summer Camp, and "Design with 3D pen" was included in the curriculum. My original idea for the first lesson was: kids create a nice car using the 3D pen. The car rolls. Everybody is happy. Lunch time.

However, I learned about Michelin's 3D printed airless tires and their visionary concept tire and I decided to upgrade the activity: what about a race cars competition to define who created the best 3D printed wheels? Most of the kids love race cars, especially in Azerbaijan, where Formula 1 is the most important event of the year, and families and tourists come to see their favorite teams competing in the streets of Baku; so creating a racetrack would bring a lot of excitement to the classroom.

But, how to release all cars at the same time? what if two cars arrive to the finish line and it's not clear who the winner is? How could we integrate more concepts to this activity?

In this instructable you will learn how to create a 4-lanes racetrack. The racetrack has a release system at top. Cars will move thanks to the effect of gravity. At the end of each track, there will be a touch sensor wired to a Makey Makey. Makey Makey will send the arrival information to a Scratch 3.0 program, that will calculate the time that each car required to arrive to the finish line.

Don't worry about the materials! You can build the track using supplies from any hardware store. Also, the touch sensors were made from trash. Even I built all this system using junk from our depot. The only high technology pieces you will need are a Makey Makey and a laptop with Scratch 3.0 installed. And if you don't have 3D pens, there is no problem! This activity can be done with Hot Wheels cars, 3D printed cars, wooden cars or any rolling vehicle as long as they don't exceed the dimensions of the release area and the track.

Concepts explored during this activity: you can cover several STEAM fields in this exercise:

  • Science: Physics concepts like gravity, traction, friction, forces applied over an object in motion, acceleration; and depending of how your students will build their cars, properties of different materials.
  • Technology: kids will understand how a sensor can detect or measure a physical property. Also, they can explore how sensors are connected to a Makey Makey board that collects the input information and send it to a Scratch program coded to analyze and display the collected data.
  • Engineering: Kids will explore simple machines like inclined plane, levers, wheel and axle. Also, they will have to apply the Engineering Design Process (Ask, Brainstorm, Design, Build, Test and Improve) to create their best car.
  • Arts: using 3D pen (or the materials and tools of your choice), kids will design and customize their own race car.
  • Mathematics: using the data collected by the sensors and Makey Makey, and measuring the racetrack and the cars, kids can calculate speed and acceleration of their car during the race. Also, they can be challenged to create a better Scratch program to calculate the time and display other interesting information about the race.

Time intensity: you can adjust this lesson according to your time and resources availability, and number of students. This lesson was completed in 2 hours for a group of 30 kids, focusing only in the car design and building, and test in the race track. However, my suggestion is to extend this activity to 4 lessons of 1.5 hours, distributed in this way:

  1. Car design: using 3D pen, CAD or assorted materials (bottle caps, bamboo sticks, cardboard, straws)
  2. Sensor construction: students learn how to build the basic touch sensor used in this activity, and test its sensitivity.
  3. Coding: kids learn how to create the basic program with Scratch 3.0, and they are challenged to make a better program to measure time and results.
  4. Testing and mathematical extension: kids are challenged to compete in the racetrack, and use math to calculate who has the fastest car.

Age group: this activity is more suitable for kids age 10 to 14 years old. I tested this lesson with 100 kids, distributed in 4 groups of 25 students: two groups in the 6 to 10 years old range, and two in the 11 to 14 years old range. If well all of them enjoyed the race, the younger groups struggled more trying to create a functional car and were not too interested in the data displayed by the computer. However, results may vary with classrooms of less kids and if design with 3D pens is changed for building with assorted materials. Also, this track can be used for older students to test cars made using CAD/CAM.

Step 1: Materials and Tools

To build the racetrack, you will need the following supplies:


  • 4 segments of gutter reference Classic120, of 1.5 meters each. Actually, these ones came in segments of 3 meters each one, so I cut them in half.
  • 4 step ends for gutter reference Classic 120. Actually, references may change, so you can pick up any suitable gutter and compatible stop ends from your favorite hardware store.
  • Wood strips
  • Sandpaper
  • Metal angles
  • Hinges
  • Assorted screws, nuts, bolts and washers.


  • Long plastic beams. I found these red ones near the trash of a copying center, so it's uncertain where to get more. However, you can replace them with wood sticks.
  • 8 CDs


  • Large circular plastic caps. Originally, I used 4 green ones from gel pots and 4 red ones from water carafes. However, I had to improve the sensor, so at the end I only used the green ones.
  • Metal bracket with hole on each end: I started using two per sensor. However, I finished using only one.
  • 2 M4X6 bolts
  • 1 M4X14 bolt
  • 1 M4X16 bolt
  • 5 M4 nuts
  • Aluminum foil tape (like this one)
  • Wires of different colors


  • 1 SPDT Micro switch (like this one). This will be installed in the release system to send a signal to the Makey Makey to start the chronometer.
  • 1 Makey Makey board with accesories
  • Cables and connectors of different colors
  • 1 plastic box to protect the Makey Makey
  • 1 laptop with Scratch 3.0 installed


  • Hot glue
  • Super glue
  • Isolating tape
  • Soldering tin
  • Materials for your race cars (I will talk about this part later)


  • Dremel rotary tool
  • Screwdrivers
  • Pliers
  • Soldering iron
  • Leatherman multitool
  • Markers
  • Measuring tape
  • Pencil
Khaslem1 month ago
do you have a link to the scratch code? or a title to search? looks great and have hand it on my to create a multi car timer
M.C. Langer (author)  Khaslem29 days ago
Hi Khaslem,

I just posted the program in the Scratch community:

Thanks for your support!
i looked closely at what you had in the image and i created this one
M.C. Langer (author)  Khaslem19 days ago
That's great! Nice touch adding the teenagers to say the time of each car.
MakeyMakey29 days ago
Great guide, M.C. Langer! We've featured it on our community hub!
M.C. Langer (author)  MakeyMakey29 days ago
Thanks a lot, Makey Makey team!
This is awesome! It looks like your students had a blast designing and testing their cars. Thanks for sharing!
M.C. Langer (author)  WeTeachThemSTEM1 month ago
Thanks to you, WeTeachThemSTEM! :-)