What Is Crunchlabs?
Crunchlabs is a monthly subscription box created by Mark Rober (the engineer/YouTuber famous for the glitter bomb videos). Each month a box arrives with components, instructions, and an explanation of the engineering principles behind the build.
The builds range from ball launchers to vacuum chambers to robotic arms. Each one teaches a specific concept in physics or engineering.
My Approach: Build Then Hack
I don't just follow the instructions. The box is the starting point. Once I've built the base project and understand how it works, I start modifying it — different motors, added sensors, custom software, structural changes. The "hack pack" name is literal.
Photos
Featured Builds
Ball Launcher
The ball launcher uses a spinning wheel mechanism to launch foam balls at adjustable speed. The engineering concept is conservation of momentum — the spinning wheel transfers energy to the ball on contact.
Stock build: Manual speed adjustment via a dial.
My mods:
- Replaced the manual dial with a servo motor controlled by an Arduino
- Added an ultrasonic sensor to detect targets and auto-fire when something enters the range
- Wrote a small targeting routine that adjusts launch timing based on distance
The result: an automated ball launcher that fires when it detects something in front of it. More fun than the manual version.
Aurora Reflector
The Aurora Reflector uses a rotating mirrored disc and LED strip to project light patterns on the ceiling and walls, simulating the aurora borealis effect.
Stock build: Fixed LED colors, constant rotation speed.
My mods:
- Replaced the fixed LED strip with individually addressable NeoPixels
- Wrote Arduino code to cycle through aurora color palettes and animate them
- Added a potentiometer to control rotation speed independently of LED animation speed
The color effects are significantly more impressive than the stock version. The NeoPixels can do things that fixed-color LEDs can't — gradients, chasing patterns, ripple effects.
NeoPixels (WS2812B LEDs) are addressable individually via a single data line. Libraries like FastLED make it straightforward to program complex lighting effects with minimal code.
Build Box Kit (Upcoming)
Each month brings a new project. I document the build and any modifications I make, and keep this page updated with each new addition.
Why I Like These Kits
They're a great way to encounter engineering problems I wouldn't naturally think to explore myself. The vacuum chamber taught me things about pressure I'd never have learned just from watching videos. The launcher taught me projectile physics in a hands-on way.
More importantly, the "hack it" mentality fits how I approach everything. Understanding why something works the way it does is always more interesting than just making it work.
The auto-targeting ball launcher has become the most popular thing in my room. Everyone who visits wants to try it — and then get pelted by foam balls.
Engineering Concepts Covered
Across the builds so far:
- Momentum and impulse (ball launcher)
- Reflection and optics (aurora reflector)
- Atmospheric pressure (vacuum chamber)
- Servo control and PWM signals (all mods)
- LED driver protocols (NeoPixel mods)