This is the Sci-Fi Lab B7, a kinetic sculpture where engineering meets imagination. This laboratory structure features a motor-driven marble system powered by a N20 motor (400 RPM recommended), which drives 4 synchronized conveyor belts lifting 8 mm steel marbles to the top. From there, the marbles descend through a network of spiraling rails winding around the lab’s core.
At the Front, a glowing blue lab tube radiates energy, while 14 interlocking gears transmit motion throughout the mechanism, creating a smooth flow. Building the B7 is a complex but deeply satisfying project — a mix of precision mechanics and sci-fi design that results in a functional marble run and a striking display piece.
Designed for 8 mm steel marbles
Powered by a standard N20 Motor from Maker's Supply
4 conveyor belts
14 interlocking gears for synchronized motion
Optional LED lighting for the blue lab tube and windows
Bill of Materials
8 mm Stainless Steel Balls
6x Micro Steel Ball Bearings MR128
N20 Reduction Gear Motor 400rpm
4 White 3030-LED Board
Self-Locking Button Switch
Power Distribution Board
SH1.0 to SH1.0 Connector Adapter Board
4x M2x6 Screws
8x M2.5x6 Screws
Assembly Instructions
Tips:
At every connection point of the rails, you can slightly rotate both rail ends to adjust the slope and fine-tune the marble movement.
The gearbox axis has small dots that indicate where to attach the clamps, ensuring that the gears and the axis stay securely in place.
Each rail is marked with a small letter to help with sorting — they start with A at the bottom and go up to T at the very top.
If some rail connections at the building don’t hold tightly enough, apply a small amount of glue at the contact points to add extra stability.
Every gear is numbered, making it easier to identify and position the correct one during assembly.
Assembly Guide Video:
Missing in the video:
Before adding the Laser-object, add the small black Rail into the hole.
At the end of assembly, add the black door with glue.
Troubleshooting
If the conveyor belt is too loose or sags too much, you have two options:
Remove one conveyor belt link and try again.
Use the alternative print profile with slightly shorter belts and test this version.
Structales - Roadrunner4d
