Texting Trapper Saved by a Faraday Cage

Texting Trapper Saved by a Faraday Cage

This is one of my favorite stories of an eleventh-hour save of a Maker Faire project. Makers Sophi Kravitz and Ollie Tanner built an 8′ bar graph that indicates the signal strength of nearby cell phones. It worked great at home, but not so much at the San Mateo Fairground:

Since the idea of the product is to detect transmitted and received signals from a good distance, I made sure that there would not be any cell towers too close to the Maker Faire site ahead of time. It was fun looking at maps of where cell towers are located!
Unfortunately, since cell service where Maker Faire is located (San Mateo fairgrounds) is poor, a temporary tower was brought in, and placed very close to the building we were exhibiting in. After setting up the exhibit, we realized that it was full on all the time, the cell tower was overpowering the exhibit and we weren’t going to be able to show anything except a big, red, bright light.

After a few failed attempts fixing their troubles with antenna design and attenuators, Sophi called in her brother, Lex Kravitz, to build a Faraday cage.

This allowed Sophi to place her cell phone under the cage, and she asked booth visitors to text her phone to see the gigantic signal strength bounce. It worked wonderfully! It was a real treat to see both the original project in action and the ingenious solution to the last-minute problem.

Texting Trapper at Maker Faire 2012

16 thoughts on “Texting Trapper Saved by a Faraday Cage

  1. electronicharry says:

    For the record: When they say a “temporary tower is brought in,” they don’t mean a little device, they mean TWO of these things: http://en.wikipedia.org/wiki/File:Cell_on_wheels.jpg , one in each parking lot, which can service 80,000 users apiece.

    1. John Edgar Park says:

      Thanks, that puts it into perspective! Now I’m even more impressed that they got it working.

  2. Bob Alexander says:

    When I saw the headline, I thought this was about an animal trapper, perhaps sitting next to a leg trap, texting on his cell phone, then a lightning storm came and he needed to protect himself with a Faraday cage.

    Honest to God, that’s what I thought this article was going to be about.

    I guess that would qualify for “you know you’re a redneck when…”

    1. Dan Martinez says:

      Mmmmmaybe it’s a redneck thing. Then again, I was raised on the northeastern seaboard by first-generation European immigrants, and I too had mental images of a guy in a raccoon cap Tweeting his status from within the metal mesh while lightning lit the wooded hills around him, so maybe not.

    2. M Lange (@errorad) says:

      OK, I’ll admit I was thinking the exact same thing… I was like, “How is a Faraday Cage going to aid someone who is *trying* to text?” It did seem a bit counter-intuitive.

  3. Sophi Kravitz says:

    You people visualizing the Woodsperson Trapper are cracking me up!
    I never even thought of that meaning and I live in a hunter’s paradise area!
    Someone needs to post a cartoon of that!

    1. Nick Normal says:

      Way to go Sophi! Sorry I missed you at Maker Faire, and glad to see you got this working!

  4. Texting Trapper at Maker Faire 2012 » says:

    […] I brought the Texting Trapper project to the Bay Area Maker Faire. Update: This project was in the MAKE: Blog … Hooray! I’m also in a Maker Faire after party video (around 8:13) from Dangerous […]

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John Edgar Park likes to make things and tell people about it. He builds project for Adafruit Industries. You can find him at jpixl.net and twitter/IG @johnedgarpark

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