Trebuchet Trials.



9 weeks




Sakshat Goyal - Prototyping
Oliver Engel - Development
Javan Wang - Management

My Role:

I led the physical prototyping for our STEM education kit.

"Our objective is to create an educational kit that could generate excitement among students about a STEM concept."

- Stakeholders.


We designed a classroom activity for students encouraging STEM education that cost less than $10 per student.

Our key audience was students between the ages of 10 to 12 years of age. 

The kit had to include an interactive physical model with sensors, and an interface that would help students visualize data received from sensors.


The final iteration of our education kit.

Ideating Concepts.

Conceiving science experiments was hard at first since creating it was outside any of our comfort zones. To resolve this issue,

we began by generating multiple ideas based on science concepts outlined in the Next Generation Science Standards. 


A snapshot of ideated concepts.

We shortlisted 3 concepts that struck a good balance between being exciting, and practical; followed by prototyping the concepts to discern any unknown variables.

Shortlisted concept from Sakshat - Hydro Turbine

Shortlisted concept from Oliver - Magic Sound

Shortlisted concept from Javan - Trebuchet (Selected ✓)


We had the opportunity to allow students and teachers to interact with our prototypes. 

Our observations and feedback helped us evaluate each concept and narrow down a single concept.


Usability results for the 3 shortlisted concepts

The viability of each concept was questionable at this stage since it required a lot of technical expertise.

To resolve this, we continued learning to use Arduino throughout the process.

Designing the interface.

Unlike a typical interface where a user can click around the screen, this prototype had to feed data from user interactions with the trebuchet. 

Without having a functional prototype, we resorted to a Wizard of Oz prototype to test user engagement with the interface. 

Using Figma, we were able to change screens in real-time as participants performed the required set of tasks with the trebuchet.


First prototype workflow.

Usability session for the prototype.


Complete Wizard of Oz prototype setup.

Our observations helped us frame some guiding principles - 

  • The interface and the trebuchet had to behave as a single entity. 

  • We had to approach the interface as a game design rather than 'data visualization'.

Resolving the accelerometer reading.


we began developing an interface that received the trebuchet arm positions through an accelerometer

and remapped the data to the rotation of the arm in the interface. By the second test session, we were able to fully resolve this issue.


Usability session with our functional prototype.

We decided to create a game where students enter fixed weight values formulating to the potential energy and examine the amount of kinetic energy generated as they release the suspended trebuchet arm. 

This way we were able to satisfy the requirement of having a data visualization, while also making it playful for a student.

Completing the gaming interface.

Designing the trebuchet.

We had to create a trebuchet that was stable, low-cost, and could be easily crafted by young students.

I explored two materials while prototyping. The first prototype was made from wooden sheets cut by CNC machines with the intention of shipping pre-made components along with the kit.

While it was promising, it significantly increased the cost of production for a kit that had to cost less than $10 per student.


Wooden trebuchet (3d model).


Wooden trebuchet assembled.

While the wooden sheets themselves were firm, the completed model was not as sturdy as we had hoped. 

I was also concerned about young students potentially harming each other during an argument with the wooden arm of the trebuchet. 


Cardboard trebuchet assembled.

Student interaction with the trebuchet.

Cardboard was the perfect material for our kit. We saw the students assemble it much faster than we expected them to, and the end result was quite sturdy.

As we made progress on technical constraints, we realized that

the sensors necessary to improve the interface experience significantly increased the cost of the kit.

This meant we had to radically change our approach with the trebuchet.

First iteration of the paper prototype.

Second iteration of the paper prototype.

Student skills, ergonomics, and common classroom supplies became the foundation for our principles while building the trebuchet prototype.

We decided to work with a simple paper prototype with the following principles.

  • A student should be able to create any component of the trebuchet out of a single letter-sized sheet or a used cardboard sheet.

  • The crafting of the trebuchet should only include three possible steps - cut, fold, tape.

  • Folds should be large enough for students with limited crafting ability to easily create the prototype.

Paper prototype setup.

Physical computing setup.

" In fourth grade, we do an energy unit and this could perfectly tie into the unit, and actually work better than some of our existing experiments... I would totally purchase this kit for our energy unit next year if you created it."

- Katie, 4th Grade Teacher.

" I would buy this for one trillion dollars!! "

- Angel, 4th Grade Student.


We shared our final design with teachers we met throughout the process. The ease of assembly and its alignment with their syllabus made it more than an extra-curricular activity. 

Teachers saw it as a great way to make learning more exciting. At the same time, students couldn't stop playing and interacting with the kit. 

We presented our design and findings at Microsoft as part of an expo at the end of our process. Among the 14 teams, we won the Best Implementation Award for its design and alignment with the design requirements. 


Oliver, Javan, and me at Microsoft HQ.


Unlike other projects, we had little expectation for this project to play a big role in our immediate professional lives. So we simply decided to have fun and enjoy the process. 

Having a team with a variety of backgrounds and skillsets was key to our project's success.

Since this was a college project, everyone in the team had to make equal contributions to all aspects of the project. That said, each of us was able to contribute to the project in our own unique way. Our unique background and skillsets, whether it was code, craftsmanship, or the ability to network and be resourceful, helped give this project the edge over its competitors.