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Minor Versionm

by Suchitha Vishwa


Using paper cups/aluminum can, some insulated wire and a magnet, create a wonderful speaker that produces sound!

    • Scissors have functional sharp edges. Contact may result in injury. Always keep blades away from fingers and body. Handle with care.

    • Be careful while handling metal pieces, they may cut the skin if handled improperly.

  1. Using scissors, cut an aluminium can to a 3.5 cm  height from its bottom.
    • Using scissors, cut an aluminium can to a 3.5 cm height from its bottom.

    • Put a drop of glue in the centre of the bottom dome on the inside.

    • Now flip the can around and place a coin on the bottom.

    • Hold the coin to the can with your finger and turn the can while still holding the coin in place.

    • Now lower the magnet onto the blob of glue you put in the centre. The magnet should now be held firmly to the bottom of the can because of its attraction to the coin on the other side.

    • Once the magnet is in place, leave this undisturbed for 10 -15 minutes, to let the glue dry.

    • Cut a square of paper measuring 5cm x 5cm.

    • In order to make the voice coil you'll need a paper cylinder with a diameter of 1.2 cm. You can use a sketch pen and wind multiple layers of tape to get to the desired diameter.

    • Now roll the paper square over the cylinder to form a tube.

    • When the paper has made one turn around the cylinder, glue it to itself and cut off the excess paper.

    • Now start winding the enamelled copper wire around the tube about 0.75 cm from one of its ends.

    • Leave about 5 cm of wire free before starting to wind the coil.

    • Start winding the coil as tightly and closely spaced as possible.

    • Once you've reached a coil width of about a centimetre, spread a little glue on the winding to secure the wire and start winding again from bottom to top.

    • Keep winding in this manner till all the wire has been exhausted. Again leave 5 cm of the wire at the end free. Then spread some glue to secure the last winding.

    • Take two pieces of connecting wire and strip about 1.5 cm of their insulation from each end.

    • Scrape the enamel from the coil ends. You can use sandpaper for this or carefully scrape it away with the scissor edge. Scrape around 2 cm of insulation form each end.

    • While scraping be careful not to pull the coil wire too much, it might break.

    • Now twist one of the coil wires and connecting wires together. And repeat with the other end of the coil and other connecting wire.

    • Secure the wire connections with insulation tape.

    • Slowly slide the paper tube off the sketch pen tube to separate them.

    • Also remove the coin from the bottom of the can.

    • Using scissors make two small holes 1 cm from the bottom of the Aluminium can and 1 cm apart.

    • Make a loop of connecting wire just before the coil wire connections and feed the other free end of the connecting wire through the loop to make a knot.

    • While tightening the knot make sure there is a little space between the tape joint and the final knot.

    • Make the same knot on the other wire too. Make sure that the knots are at roughly the same place on the wire.

    • Now take the end of the insulated wire and push it through the hole on the can from the inside to the outside.

    • When the wire is pulled the knot should get caught at the hole; this helps relieve the stress on the connection joint.

    • Repeat the process with the other wire and the other hole.

    • Now glue the wires to the inside of the can and leave them to dry.

    • Mount the paper tube on the magnet with the coil side on the bottom.

    • At this point the coil assembly should look like this.

    • Cut the paper tube to about 1 cm taller than the cut can.

    • Start with a rectangle piece of butter paper, about 8cm x 7cm, and fold the longer side in half.

    • Now fold it again along the other axis.

    • Using scissors cut off the corner where all four sheets are folded. (This corner corresponds to the centre when the sheet is opened.)

    • When you open the sheet (your diaphragm), you should have a diamond shaped hole in the center.

    • Stretch the hole over the paper cylinder you used to wind the coil.

    • Now place the cylinder into the paper tube.

    • Now gently push the diaphragm from the cylinder onto the paper tube.

    • Push the diaphragm a little more than one centimetre down the paper tube. This will make sure that the coil isn't resting on the bottom of the can, but is instead suspended from the diaphragm.

    • Glue the paper tube to the diaphragm, taking care that the glue doesn't leak into the can.

    • Now carefully cut the excess paper above the diaphragm.

    • Flip the can with the diaphragm still in place.

    • Now glue the diaphragm to the rim of the can. Make sure that every part of the diaphragm is glued to the edge of the can.

    • Ensure the paper tube is aligned above the magnet, with a small uniform gap between the magnet and tube.

    • When the glue begins to set, cut off the excess parts of the diaphragm. Leave a little extra of the diaphragm around the rim of the can. Fold this extra section down onto the can body to make the seal more robust.

    • Strip the insulation off the open end of the audio cable to expose the three insulted wires inside. These wires are colour coded, red or pink for the left channel and grey or black for ground.

    • Connect the wire of the completed speaker to the left and ground wires.

    • Tape the wire joints with insulation tape. Make sure the joints don't touch each other when you are taping them.

    • Once the cable has been securely attached, the speaker is complete.

    • To ensure the best sound quality and loudness,ensure that the gap between the magnet and coil is maintained.

    • Plug the jack into a music source, such as a phone, mp3 player or computer, turn on the music and listen with your ear against the bottom of the can!

    • If the speaker doesn't produce sound, this could be because of a loose connection in the connecting wire or a break in the coil.

    • If the sound produced is low in volume, adjust the diaphragm position and tension till the volume increases.

    • To ensure the best sound quality and loudness ensure that the gap between the magnet and coil is maintained and the coil is right above the pole of the magnet.

Finish Line

Kailash NR

Member since: 05/02/2017

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78 Guides authored