Wood (and lots of it):

• Various types of plywood - a future version will use hardwood for the sound chambers.
• 3/4" Solid (Poplar, Oak, etc) Boards
• Various Size Round Dowels
• 1x1" Poplar Square Dowels
• Bamboo Skewers
• Large Wooden Beads

Adhering:

• Wood Glue
• Screws (and a LOT of them, I went through over a hundred)
• Bolts for attaching sound chambers

Tools:

• Drill and Driver
• Clamps - I bought a ton of dollar clamps from Home Depot, plus a few larger clamps
• Good Ruler/Protractor/Square
• Scroll saw
• Drill Press - with various bits and hole saws
• Belt sander
• Dremel
• Orbital sander
• Various hand tools for tweaking

Other:

• Soprano Ukulele Strings
• Tuning pegs
• Guitar Pick
• Motor and Hookup Wire - I used a motor from a video cassette rewinder, along with other bits from the machine, such as the belt and pulleys
• Zip Tie
• Wood Stain, Multiple Colors

I went through various types of plywood in the learning/tinkering process of building the sound chambers. By the time I got to the nice 1/8" baltic birch ply, I had refined the design, process, and my skills to have a satisfying result.