LED Jellyfish
30-60 min
Ages 8+
What Will You Make?
Make a jellyfish-shaped casing for LED throwies! Here’s how to make a jellyfish-shaped casing for LED throwies that you can stick to any metal surface. The throwies are easily removable so you can “refill” the jelly and use it over and over.
What Will You Learn?
Learn a simple electrical circuit as well as a simple running stitch. Discuss how magnets work. Practice measuring and cutting. Then get creative as you decorate your jellyfish.
Cut Out Pieces
Step 1
Cut out 1 circle of batting (~5.5″ diameter) and 2 circles of fabric (~8″ diameter). We suggest you create paper or cardboard templates and trace them to the fabric. These fabric sizes are made for plastic bubbles that are about 2″ in diameter. If you have a bigger or smaller bubble you can adjust as needed.
Step 2
Cut some pieces of ribbon for your “tentacles.” We made our ~6″ long. The number will depend on your personal tastes and the size of the plastic bubble. This example has about 9 tentacles.
Attach Tentacles
Step 3
Take the plastic bubble and glue your ribbon tentacles to the clear top section. Make sure not to glue the top and bottom of the bubble together – you’ll want to be able to open it up and place your throwie in later on. I drew a line to help keep my tentacles even and out of the way.
Sew the Body
Step 4
Place your batting, centered, on top of the 2 pieces of fabric. Fold the fabric over the batting and pin.
Step 5
With a needle and thread, sew through your layers of fabric and batting ~ 1/4″ from the edge of your overlap. Be careful not to do any back stitching. When you are finished, pull the thread to gather the fabric and make a scrunchy jellyfish shape (do not knot or tie off just yet).
Glue the Body
Step 6
Place your jelly body over the top of the plastic bubble. If you need to, adjust the gather so that it is snug and tie a knot to finish it.
Step 7
Glue the fabric to the plastic bubble, covering the tops of the ribbon tentacles. Again, make sure not to overlap the bottom; leave ~1/4″ of space to work with.
Get those LEDs Ready
Step 8
Take your LEDs and use a pair of pliers to bend the leads at right angles, with the anode (longer lead) on “top.” This will give you more space inside the bubble and also point the light upwards. Leave ~1/8″ space between the leads, just enough to slide the battery between them.
Step 9
Add a drop of hot glue between/around the leads before the bend to make sure they don’t accidentally touch.
Make Throwies
Step 10
Slide an LED onto one of your batteries (if the leads extend past the battery, shorten them with some wire cutters).
Wrap it up in tape, making sure that it is nice and secure and doesn’t flicker.
Place one of your magnets on top (positive side) and wrap up some more tape so it doesn’t slide.
Step 11
Repeat Step 10 with your second LED, and place it on top of the magnet.
I oriented my LEDs opposite each other to cast more light throughout the jelly. Place a second magnet on top of that and wrap up with more tape.
You don’t really need this other magnet, but it adds a little extra holding power.
Assemble the Jelly
Step 12
Your final magnet will attach to the bottom of the plastic bubble and hold your throwie in place. Make sure it is oriented the right way before gluing by testing it out on the bottom of the throwie “pile.”
Hot-glue the magnet to the center of the inside of the plastic bubble and place your throwie on top. Then just snap the top of the bubble back on and enjoy!
At this point you can add some finishing touches; maybe some embroidery or a happy face. I separated the strands of my ribbon tentacles to get more of the wispy/stringy look. You can also try out different combinations of LED colors and plastic bubbles.
Although these are throwies, the plastic bubbles are pretty brittle. I don’t recommend tossing them at things. I had a few bounce off surfaces and break when the magnet didn’t catch.
What Is Happening Here?
Magnetism
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomenon in other entities. Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets. Ferromagnetism (along with the similar effect ferrimagnetism) is the strongest type or magnetism and is responsible for the common phenomenon of magnetism in magnets encountered in everyday life. The super strong magnets used inthis project are made from neodymium, iron, boron and a few transition metals. They’re some of the strongest magnets in the world. LED Throwies use ferromagnetism to stick to certain metal surfaces.
Circuits
An LED (light-emitting diode) is used when bright, low power and low heat lights are needed. In a diode, electrons rise to and fall from precise energy levels. When an electron falls to a lower energy level, light energy is emitted. It’s the size of the fall (the gap) that decides the frequency of the light (i.e. the color of the visible light).
LEDs are polarized, which means they have a positive and negative side. Electricity must flow through the LED in the correct direction. This project uses about the simplest circuit you can make: a power source (the battery) and a load (the LED). The leads of the LED work as the conductive material allowing the electricity to flow through the circuit.
LEDs are found in all kinds of devices from numbers on a digital clock, to kitchen appliances, to traffic lights, and even jumbo-tron screens.
What' Next?
Additional Resources
Introduce your campers to electric circuit theory with this great the article, “Make throwies to learn Ohm’s Law.“
Continue the water theme with LED Swimmies or Floaties.
Why not expand your sewing and circuit skills with this Soft-Circuit LED Bracelet?
This project first appeared in Make: Magazine in December 2012. It was written by Angela Sheehan. Angela is a maker and educator passionate about DIY electronics, costuming, and craft tech. She has been tinkering with wearables since 2005. Find her projects on GellaCraft.com, Twitter @the_gella, and Instagram @gellacraft.
Materials:
Ribbon
Fabric, sheer/translucent
Quilt batting (1)
Thread (1)
Plastic bubble (1) from arcade or toy vending machine
Rare earth magnets (3) 3 per jelly
Diffused LEDs, 10mm (2)
Coin cell battery, 3V Lithium, CR2032 or CR16161 (2)
Hot glue gun
Marker or pencil
Needle
Needlenose pliers
Scissors
Sewing pins
Tape
