Speakers are so common in the world, but do you know that you can make primitive one very easily? Using conductive ink pen, your simple drawing can work as a speaker. Let's see it works!
A coil drawn by a conductive ink works as a speaker, as the video shows. Draw your own speaker and play with it.
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Prepare Materials
You will need the following materials to begin with.
- AgIC Circuit Marker or AgIC Circuit Printer, and special paper (you can find them here)
- Audio amplifier, such as Lepai LP-2020A
- 1" diameter neodymium magnet, such as ones from Neodymium Magnets
- 2 aligator clip cables
- 1 male-male stereo audio cable (one we use to connect audio device to a car)
Optional: stencil to draw circles or rectangles (if you use Circuit Marker)
Step 2: Make a Coil
The point of this step is make a coil on paper using AgIC conductive ink. Follow the instruction below depending on which tool you use:
- With Circuit Marker: Draw an incomplete circle, leaving some slice, in the center of the paper. We recommend to use a stencil. Do not close the circle - otherwise it shorts out and the coil does not work. Draw two lines from the incomplete parts to the edge of the paper - these will be contacts to the amplifier.
- With Circuit Printer: Download the attached template and print with your Circuit Printer.
Step 3: Connect Things
Connect all components together:
Your audio player (phone etc...) <-(male-male audio cable)-> amplifier <-(alligator clip cables)-> paper with the coil
You may want to cut one side of alligator clip cables, and peel the cover so that you can insert them to amplifier easily.
Step 4: Hover Coil and Hear the Sound!
Turn on the amplifier, and play a music. Then hover the coil over the magnet. You should hear the sound when the circle goes on top of the magnet! Move the coil and listen how sound changes.
If you do not hear the sound, increase the volume of the amplifier. Also make sure the alligator clips do not scratch out the silver drawing.
Step 5: Try More Shapes!
From our research, the coil can be any incomplete circular shape, such as circle, rectangle, or star. See some examples in photo from an event at the Tech Museum of Innovation - it is surprising (even for us) that all worked well. There are good Instructables for your references and inspirations (explorations and amazing works). Let's try with your own shapes and listen how it works!
Step 6: Why It Sounds?
As you may have heard in science class, sounds can be made from vibrations of materials (which vibrates the air). A very simple speaker can be made of a magnet and a coil where audio signal flows as electrical current. The current generate magnetic force and react -pull and repel- with the magnet, which causes vibration of the coil. In this project, you will draw/print a coil with AgIC's conductive ink.
There are more information on web, such as one by Physics.org.