Build a simple homemade cell phone speaker using cups, cardboard, and tape to amplify sound and explore basic acoustics through hands on experimentation.


Step-by-step guide to make a homemade cell phone speaker
Step 1
Clear a flat table and lay out all your materials so you can reach them easily.
Step 2
Use the pencil and ruler to draw a large fan shape on the cardboard about as wide as a cup opening.
Step 3
Cut out the fan shape from the cardboard with the scissors while an adult watches.
Step 4
Roll the cardboard fan into a cone shape so one end is small and the other end is wide.
Step 5
Tape the long edge of the cone to hold it closed so it keeps its funnel shape.
Step 6
Trim the tiny tip of the cone so the small end makes a hole that will fit into a cup mouth.
Step 7
Cut a horizontal slot near the rim of one cup that is wide enough to hold your phone snugly while the speaker faces into the cone.
Step 8
Push the small end of the cone into the mouth of the cup with the slot and tape the cone to the cup to make a tight seal.
Step 9
Fit the wide end of the cone into the mouth of the second cup and tape them together to form a bell-shaped amplifier.
Step 10
Turn on a song or sound on your phone at a low volume.
Step 11
Slide your phone into the slot with the speaker facing the cone so the sound can travel into the funnel.
Step 12
Move the phone forward and backward a little to find the loudest spot and try flipping or removing the outer cup to hear the difference.
Step 13
Take a photo or video of your finished speaker and share your creation on DIY.org
Final steps
You're almost there! Complete all the steps, bring your creation to life, post it, and conquer the challenge!

Help!?
What can we use if we don't have cardboard or disposable cups from the materials list?
If you don't have sturdy cardboard to draw the fan shape on, substitute a cereal box or poster board to cut the fan, and if you lack cups use two matching yogurt tubs or trimmed plastic bottles with similar mouth diameters.
My cone keeps falling out of the cup or the speaker sounds muffled — what should I check?
Check that you taped the long edge of the cone to hold its funnel shape and firmly tape the small cone-to-cup seal (the step where you push the small end into the cup), trim the tip for a snug fit, and reposition the phone in the slot while playing a sound to find the loudest spot.
How can I adapt the steps for different age groups?
Have an adult pre-draw and cut the cardboard fan and cut the cup slot for preschoolers, let elementary kids roll, tape and trim the cone themselves under supervision, and challenge teens to experiment with cone angle or cup material to improve amplification.
How can we extend or personalize the homemade speaker once it's assembled?
Decorate the cups and cone with markers or stickers before assembly, try stiffer cardboard or different cup materials to change the sound, and test variations by moving the phone forward/back as described to compare which design is loudest.
Watch videos on how to make a homemade cell phone speaker
Facts about acoustics and sound for kids
♻️ Cardboard is lightweight, stiff, and easy to shape, which is why it’s a favorite material for DIY acoustic projects and speaker cones.
📣 A paper or cardboard horn focuses and directs sound waves, helping a tiny phone speaker seem louder without extra power.
🔊 Making a funnel or cone can boost perceived loudness by about 3–6 decibels — enough to notice in a quiet room.
📱 Most smartphone speakers are only a few centimeters wide but still produce sound across much of the human hearing range (about 20–20,000 Hz).
🧪 The hollow space inside a cup acts like a resonator that can amplify certain pitches, similar to how a guitar body or violin works.


Only $6.99 after trial. No credit card required