DIY

3D Print Planetary Gearset

The .stl files are available here:

From Thingverse:

Origial desing by Emmett Lalish Download: Gear Bearing 

Refined version featured here by Don Stewart Download: Honeycomb Gear Bearing 

Similar prints available as fidget toys here:

From Etsy: BUY NOW: Gear Spinner Fidget Toy

3D Print Planetary Gearset: amazingly this gear set is printed assembled, with interlocking herringbone teeth. The gears will not come apart, in fact this design can only be accomplished by 3D printing the gears interlocked with each other. Designed and first printed by Emmett Lalish in 2013, and this version with refined precision and honeycomb by Don Stewart. 

Hoberman Actuator with Sphere

The Actuator mechanism is out of production but can still be found on eBay, comes with power supply, Expandagon kit, and connecotors that snap on to a Hoberman Spjere. 
From eBay: BUY NOW: Hoberman Actuator

The spheres are still in production and come in various sizes and colors: 
From Amazon: BUY NOW Hoberman Spheres 

Hoberman Actuator with Sphere: This actuator mechanism creates kinetic art out of a Hoberman sphere, designed to smoothly expand and contract the isokinentic structure. The Hoberman sphere itself is a special assembly of foldable linkages consisting of rigid bars and simple hinges is kinematically over constrained- motion can only occur along the radial direction and the movement of any hinge creates motion in all the joints. The engineering and physics behind deployable space structures!

Vibration Unthreading

Get inexpensive small motors and accesories for DIY projects here:
From Amazon: BUY NOW DC Motors Kit

A DIY project to see if just shaking a bolt at the right frequency could make a standard nut rotate and fall off. Similar physics to the phase locking propeller toy featured in my last post. Motivated by videos seen on Instagram where a brass bolt is placed in magnetic putty and the nut mysteriously rotates up and off- now convinced that vibration is how that effect is produced. Here a small DC motor spins an offset mass to produce the vibrations.


Cartesian Diver

Glass divers available here: 
From Amazon: BUY NOW Glass Divers or this complete set Cartesian Diver Kit

Inexpensive and fun diver kits to make in a bottle available here: 
From Educational Innovations: BUY NOW Cartesian Diver Kits 

Wikipedia has the details on the Cartesian diver (and reverse diver)

Cartesian Divers: increasing pressure on the water compresses the air bubbles in the small glass vials filling them further with water making them sink. Pascal's principle states that any change in pressure on an enclosed fluid (such as pushing on the rubber cover) is transmitted evenly to every part of the fluid- the physics of hydraulic brakes! Named after the physicist and philosopher Rene Descartes.