With the marker, darken the long, positive (+) legs of all your LEDs so you can easily keep track of them.


Using scissors, cut two lengths of conductive thread a bit shorter than the inside of the jar. Use electrical tape to attach one piece of thread to the smooth, positive (+) side of the battery, and the other piece of the thread to the bumpy, negative (-) side of the battery.

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Choose one LED and tape its long, positive (+) leg to the thread attached to the battery’s positive (+) side. Then tape the LED’s shorter, negative (-) leg to the thread attached tot he battery’s negative (-) side.

Now that you’ve made a complete circuit, your LED should light up: You’ve made your first firefly.

Project step photo 2


Tape the battery with your lit-up LED to the inside of the jar’s lid.


Add another firefly to your assembly by twisting the legs of a second LED around the conductive thread. You can use your fingers to bend the legs into place, or use needle-nose pliers, if you prefer. Be sure you attach the LED’s long, positive (+) leg to the positive (+) thread and the LED’s short negative (-) leg to the negative (-) thread, as before. Secure with electrical tape.

Project step photo 2


Use more batteries and LEDs to make as many fireflies as you want, taping each new battery to the top of the jar, and twisting in extra LEDs where you can. Mix up blinking and nonblinking LEDs for a realistic look, but be careful not to crowd the LEDs. Try to place them along the edges of the jar so the conductive threads don’t cross one another and short out your circuits. (If you want, fold strips of electrical tape lengthwise over any exposed conductive thread.)

Please Note

Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Power tools, electricity, and other resources used for these projects are dangerous, unless used properly and with adequate precautions, including safety gear and adult supervision. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. Use of the instructions and suggestions found in Maker Camp is at your own risk. Maker Media, Inc., disclaims all responsibility for any resulting damage, injury, or expense.

Firefly Nightlight

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If you'd rather play with bulbs than bugs, these bottled-up "fireflies" are great! They'll glow for hours on end, creating a colorful nightlight that will spare the innocent fireflies of the world, while lighting up the night with a twinkly glow.


  • Conductive thread
  • Several 3V coin-cell batteries (CR2032)
  • Electrical tape
  • Several blinking LEDs (and a few nonblinking if you want)
  • See-through jar with a screw-on lid
  • Black marker
  • Scissors
  • Optional: needle-nose pliers