Create your own Kypruino / Arduino interactive Easter egg!
Introduction
Easter egg hunts are all about finding hidden surprises — so what if the egg could react when you discover it?
In this project, we turned a simple 3D-printed egg into an interactive object that lights up and plays a sound when someone gets close. Using a translucent shell, a Kypruino board, a PIR motion sensor, and a light-and-sound sequence, the result is an Easter egg that “celebrates” when it is found.
This blog post walks you through how we built it — from design and assembly to programming and final result.
Why We Built It
Easter egg hunts are fun, but traditional eggs don’t react when you find them. We wanted to add an interactive element — something that detects motion and responds instantly with light and sound.
Goal: an egg shell + motion trigger → glowing colour animation + rewarding sound effect.
Components & Tools
- Kypruino board – NeoPixels & Buzzer
- PIR motion sensor
- 3x male-female DuPont wires
- USB cable for power
- 3D-printed egg shell (translucent filament)
- Arduino IDE for programming
Kypruino
The Kypruino is what brings the project to life — acting as the brain that coordinates everything.
It is a compact, programmable board that can read inputs (like motion sensors) and control outputs (like LEDs and sound). With built-in NeoPixels and a buzzer, it allows us to create interactive effects without additional hardware.
Once programmed and powered, it continuously checks for motion and triggers the response automatically.
PIR Motion Sensor
The PIR (Passive Infrared) sensor detects movement by measuring changes in infrared radiation.
When a person approaches the egg, the sensor detects the change and sends a signal to the Kypruino, triggering the lighting and sound effects.
- Sensing angle: ~100°
- Range: up to 7 meters
- Adjustable sensitivity and delay
Designing & 3D Printing the Egg
We designed the egg as a two-part 3D print, allowing easy access to the electronics inside.
- Create a hollow interior to fit the components
- Add a small opening for the USB cable
- Ensure a stable base for placement
Using translucent filament allows the light from the LEDs to spread evenly, creating a soft glowing effect.
Wiring & Electronics
Inside the egg sits the Kypruino board, with the motion sensor positioned to detect nearby movement.
Connections:
- PIR VCC → Kypruino 5V
- PIR GND → Kypruino GND
- PIR OUT → Digital pin 7
Position the motion sensor facing outward so it can easily detect movement.
Power is supplied via USB, keeping the setup simple and clean.
Programming the Effect
The behaviour of the egg is controlled through code.
When motion is detected:
- LEDs flash briefly for instant feedback
- A smooth pastel colour animation plays
- A short “reward” sound is triggered
- The system resets after a short delay
The combination of smooth colour transitions and sound creates a playful, game-like experience.
You can find and modify the code to experiment with different colours, speeds, and sounds.
Final Result & Experience
Once powered, the egg waits silently until someone approaches. As soon as motion is detected, it flashes, glows with soft pastel colours, and plays a short celebratory sound.
The translucent shell enhances the effect, making the light appear smooth and diffused.
Possible Future Enhancements
- Experiment with different colour animations
- Create custom sound effects
- Add more sensors for new interactions
- Use a battery pack for portability
Conclusion
This project combines 3D printing, electronics, and programming to turn a simple object into something interactive and engaging.
By adding motion detection and feedback, we transform a traditional Easter egg into a small interactive experience.
It’s a great example of how technology can enhance even the simplest ideas.