Patches of the East Coast are buzzing with the return of the 17-year cicadas. They're carpeting spots from GA to CT, and filling the air with a 7 kHz mating buzz. Alert scientists when you see them emerge — or help predict their arrival with a home-built sensor!

Hover over the dots for details.
  • From Georgia to Connecticut, baby magicicadas, or "nymphs," have been sleeping and feeding on the juice of tree roots underground for 17 years. They emerge when the soil temperature reaches a steady 64° F.

  • Build a detector to monitor the soil 8" down. . .

  • . . . and use the nine LEDs on the detector to report your temperature to Radiolab. A steady 64° F indicates the cicadas should arrive!

  • A week after emerging from underground, the male magicicada begins its mating call. The female magicicada responds by flicking its wings. A mating ritual ensues to spawn the next brood of magicicada!

  • You can hear the magicicada's call. You won't miss it!

  • Once they have emerged, it takes about a week for magicicadas to shed their final "skin" and reach adulthood.


See Cicadas?

When you see or hear cicadas emerge, we want to hear about it — and so do bug scientsts! Fill out the report form, and we'll send your data to research scientist John Cooley and professor Chris Simon at the University of Connecticut Ecology & Evolutionary Biology department. They're tracking this once-in-a-17-year event for science.

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Build Your Own Sensor

Magicicada Brood II will make its 17-year appearance when the ground 8" down is a steady 64° F. Help predict the arrival by planting a homemade temperature sensor in the ground and reporting your findings back to to Radiolab. We'll put them on a map and share your observations with the world.

The whole detector costs about $80 in parts and takes about 2 hours to build. You'll want it in the ground by mid-April, the earliest the cicadas are likely to emerge.

You can also participate — and save money — by buying a soil thermometer that will detect the temperature 8 inches underground, such as this one that costs less than $8. If you've got other creative ways to build or buy a detector, let us know!

Parts List

  • An Arduino Uno, available from Adafruit, Sparkfun or RadioShack. (The Arduino Due, Mega and Leonardo models also should work.)
  • A SideKick Basic Kit for Arduino from RadioShack. From this kit, we use the following items, which you can also buy separately:
    • Breadboard
    • Thermistor
    • 9 LEDs (2 legged, any color)
    • 9 - 330-ohm resistors
    • 5 - 10K-ohm resistors
    • 11 short jumper cables
    • 4 longer jumper cables
  • Wrapping wire
  • USB A-B cable
  • Electrical tape
  • Plastic baggie
  • 12-inch long wooden dowel
  • Scissors
  • A laptop computer to configure the Arduino and power it when you take a reading. You can also power Ardiuno with a 9V battery and this connector.

Finished Detector

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Diagram of finished cicada detector kit

Assembly Guide


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Code and Deploy

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Take Readings

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Photo for Step 01


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Decode Temperatures

To decode the temperature, click on the green buttons so they match your detector's LED pattern:

Temperature is 10 °F

If you've used a soil thermometer, enter the temperature here:

Illustrations by Louise Ma / WNYC.
Built by Adam DePrince, Steven Melendez, Louise Ma and John Keefe / WNYC.

Radiolab is supported, in part, by the National Science Foundation.