New UGears STEM LAB Models coming soon! Learn how Random Generator works.

We are excited to announce that UGears have recently released two new STEM models: Variator and Random Generator. While we anxiously waiting to add those new kits to our store, we wanted to learn how both mechanisms work and share it with you. In this blog we are reviewing UGEARS STEM LAB  Random Generator.  Happy reading!

 The article about Variator can be found here. 


STEM LAB by UGEARS Random Generator is a device that generates random numbers - answers, based on probability theory. If you have ever bet on heads or tails, this means you got close and personal with its practical application. Ugears suggests an alternative to the classic coin solution that is not only elegant and fun but has an extra educational benefit.

The model kit comes with a QR-code to the study guide about the mechanism, the principal of its working, the main characteristics, formulas. It also includes interesting assignments.

Ugears Stem Lab Random Generator

The main element of the 3D puzzle Random Generator’s design is a cube with an octahedron inside it that in its turn contains a metal ball to provide weight. This construction is powered by a rack-and-gear drive initiated manually and providing energy through a driven gear that rotates a three-axle gear. 

The vertices of the octahedron coincide with the sides of the cube. In this way as the energy of the system expires and it stops moving, gravity suspends the metal ball in the lowest part of the octahedron and due to the inclination of the walls it rolls within, it ends up in one of the octahedron’s vertices pulling in down. Whichever of the vertices turns up in the bottom, the side of the cube it is attached to will be right under it and parallel to the floor. In this way, the side of the cube with the answer will be the one facing up on the opposite side.

The probability to get any of the vertices facing down is virtually the same due to symmetry of the octahedron that rotates freely around the axis of its mass. This leads us to a simple conclusion that the probability to receive one of six answers is 1/6 or 0.167.

Every side of the cube positioned by the vertex of the octahedron, has a message: one says “YES”, the other “TRY AGAIN”, etc.

The mechanism of the Random Generator is composed of:

Ugears Stem Lab Random Generator Parts

  • Button
  • Rack-and-gear drive
  • Overrunning clutch
  • Driven wheel
  • Three-axle gear
  • Cube
  • Internal octahedron
  • Weight 


    Ugears STEM puzzles are designed to suit different age groups with a special focus on learning component. The assembly of the model will be interesting and won’t take much time.

    STEM lab Model kits come with all you need in a box.

    Just like the rest of Ugears wooden model kits, putting STEM lab models together is fun and comprehensive: everything you need to build, learn, and discover comes in a box. There you will find:

    Ugears Stem Lab Random Generator Kit



    • Wooden details pre-cut with a precise high-tech laser in high-quality plywood boards, as well as other materials required for assembly. DIY kits need no glue or additional instruments to build. The details come out of the board with a slight push.
    • Step-by step illustrated assembly instruction manual.
    • Practical lab tasks with use of your model.
    • QR-code to download a pocket study guide about the model, its mechanism, principle of its working, main characteristics, physical and mechanical formulas, and fun practical tasks.
    • QR-code to download AR-application. Fascinating innovation from Ugears – new drive to learn more new things!
    • Model size: 6.81*4.8*5.2 in (17.3*12.2*13.2 cm)
    • Package size: 8.07*7.4*2.48 in (20.5*18.8*6.3 cm)
    • Number of components: 160
    • Estimated time of assembly: 4 hours

    We will be adding this intricate, functional, and educational model to our store soon! Be the first one to know! Sign up for our newsletter and receive 10% off your next purchase!