Variable Speed Shake Table (Updated 3/2021)

Here's a fairly easy way to build a variable speed shake table for earthquake engineering simulations in various classes. It's now new and improved with a 3D-Printed Flywheel and controller box!

Supplies

Electronics that can be purchased on Amazon:

• 12V Motor (This one should work as the one I used is no longer on Amazon)
• On/Off Switches
• 12V 2A Electric Plug
• Speed Controller

You'll also need:

•  a couple sheets of plywood (Mine are 70cm X 50cm and 50cm X 50cm)
• ~50cm of 1/8" metal rod to make the pushing mechanism.
• 3" of Hanger Strap (Metal strip with holes)
• a drill w/ various bits.
• 4 carriage springs: 6" tall x 3/4" diameter 
• Wood dowels that fit inside of carriage springs (1/2" Diameter or so)
• 3D printed control box (STL File)
• 3D printed Flywheel (STL File)
• Repurposed wire from old cords
• Old corrugated plastic political yard sign
• Small disk magnets (regular strength, not super strong neodymium) 
• Wood Glue/Gorilla Glue
• PocketLab Data Recorder

Constructions:

Since I don't have images of the actual construction, I'll do my best to recreate the step-by-step with the finished product. 

1.  On the piece of plywood that will be the top section of the shake table, Measure in 1" from each corner of the top piece of plywood. Mark the intersection.
2. Use a 1/2" drillbit to drill through the plywood at each intersection.
3. Cut the 1/2" wood dowel into 1.5" lengths. These will become the legs that are inserted into the springs. 
4. Flip the wood over (to the underside).
5. Apply lots of Elmers Glue into the drilled holes and the top ends of the dowels. 
6. Insert the dowels until the ends are flush with the topside of the board.

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#shakeandbreak 6th period pic.twitter.com/GKtl5kQ3MP

— Ryan Hollister (@phaneritic) February 28, 2018