Procedure:

First we build a coil on the end of the plastic cup which will be used to convert audio signal into electromagnetic waves

Materials / Part 2 / Main Page

 

Step 1:

• Cut a 1/4" length off of the soda straw. Use a hot glue gun to attach it to the bottom of one of the plastic cups.
  

  Note: Before attaching the soda straw, make certain that the small magnet will move freely inside the piece of soda straw.

 

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Step 2:

• Wind 100 turns of #33 enamel-coated copper wire onto the soda straw that is attached to the cup. (The number of turns can vary from 50 to 150 turns. 100 is optimal).

 

 

Step 3:

• Burn and sand off the enamel from the coil wire ends.
• Strip off about 1/2" of insulation from two telephone wire leads.
• Twist and solder the coil wires to the telephone wire ends.
• Use the hot glue to attach the telephone wires to the side of the cup.