Epic Jefferson
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Smartphone EMF Detection

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Rapid Prototyping | Physical Computing | Tangible Interaction | Electronics | Wood Working

Smartphone EMF Detection

Visualize the phones' electro-magnetic activity, even when the phone is "asleep".


Smartphones have become a part of us, but we still do not know how the signals affect our bodies. This project attempts to bring our attention to the phones' electro-magnetic activity, even when the phone is "asleep".


The Official Story

Officially, the task was to use Adafruit’s Electret mic to take something from the background and call attention to it in a “non-invasive” way. The first thing I remembered was that the radioshack phone pickup that I have made some interesting noises when held close to any electronic device. Since this thing is essentially just like a guitar pickup (just a copper coil wrapped in a circle), that means it’s sensitive to disruptions in it’s electromagnetic field. If a phone can interrupt it’s EMF, we can use that to trigger an action to visualize the phone’s EMF activity.

Radioshacks’ device works well for converting EMF activity to the audio spectrum, but passing that into the Electret mic and then into arduino for processing made it highly susceptible to noise, actual noise, coming in through the mic.

EMF guts

Wood Work

 I wanted to practice woodworking and make use of CMU’s awesome woodshop, so I decided to make the enclosure out of Walnut. The guys at the woodshop are incredibly knowledgeable and helpful, so I finished with this little box after about 10 hours of milling and  band-sawing and sanding over 2 days.

I found a video tutorial for an EMF detector from MAKE: Aaron Alai’s EMF Detector circuit. With a simple adaptation of the circuit and code, I was able to make it sensitive enough to detect the small electrical pulses emitted by any cellphone.


September 2014