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280 Making Things Move

he projects below draw on the skills you’ve learned in several of the chapters in
Tthis book.

P roject 10-1: Not Lazy Susan

In this project, we’ll use a lazy Susan (also called a turntable or thrust bearing) to
create a rotating platform. To make things interesting, we’ll use an infrared (IR) LED
1,2
and phototransistor to make the table rotate with just a wave of your hand. You can
use this as a table to magically serve food to dinner guests, or to make a fun interactive
centerpiece for the next wedding you plan.

If you did Project 6-7 with a transistor and Project 6-8 with a photocell, this will be
easy. If not, don’t worry—we’ll still go step by step. We’ll build the box first, then the
circuit, and finally integrate the two. As always, it’s a good idea to skim through the
steps and take a look at the pictures before getting started.
Shopping List:

• Hardware
• Safety glasses
• GM series plastic wheel from Solarbotics (fits on GM9 motor)

• Shaft adaptor (see the resources section on www.makingthingsmove.com to
download a 3D printable file or buy this part; use Alibre Design to modify if
necessary for your particular motor, wheel, and material thicknesses)

• Two pieces of 1/2 in thick MDF (or other wood) cut to 8.5 × 8.5 in square
(for the top and bottom of the box)

• Four 7 3/4 in sections cut from a longer standard 1 × 3 board (actual cross
section 3/4 in × 2 1/2 in)

• One piece of 3/16 in thick 8 1/2 in square Masonite for the rotating top
(the one here is a laser-cut circle, but yours can be any shape or thickness)
• Wood glue (Titebond or Elmer’s Wood Glue, for example)
• Clamps