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2.4GHz Wi-Fi Detector Ring Project

Posted by CmdrTaco on from the check-out-my-bling dept.

mohrt writes "The Wi-Fi detection ring was developed to give mobile computer users the ability to detect 802.11b/g signals, while providing a unique, fashionable and ultra-portable product package. The prototype circuit collects and rectifies an RF signal in the 2.4GHz range, whereafter an Atmel Tiny microprocessor, detecting the presence of a DC voltage, thusly engages a flashing LED. For those of you who have no excuse to wear a ring, well here it is."

6 of 248 comments (clear)

  1. Don't forget microwaves... by PMJ2kx · · Score: 4, Informative

    From the article: "Due to the simplicity of the circuit design, the prototype unit does not discriminate between other sources of 2.4GHz RF, eg. "leaky" microwave ovens, cordless phones, etc. Future production units would feature surface-mounted components to decrease the detector profile and microcontrollers that discriminate between other RF sources, as well as indicate whether the Wi-Fi nodes are open/closed/encrypted, etc."

    Yes, but they're going to fix that.

  2. Re:Why use a CPU? by winavr · · Score: 1, Informative

    You just answered your own question (why they need a cpu).

    "They mention a future revision doing interpretation of the open/closed/encrypted state of the WiFi node".

    Sounds like they'll need a cpu to do that, unless you think they can do that just with an analog comparator chip.

  3. Three rings by rlp · · Score: 3, Informative

    That'll look real nice right next to my Java ring. :-)

    --
    [Insert pithy quote here]
  4. Re:Silliness. Using a processor is massive overkil by Anonymous Coward · · Score: 1, Informative

    You can get attiny11s microcontrollers at a lower cost than most (not all, admittedly) 555s. They'll run on an internal RC oscillator and don't require external components to set timing intervals. For many applications it wouldn't surprise me if people used that as an alternative to a 555.

  5. Re:Why use a CPU? by Migraineman · · Score: 2, Informative

    No, the RF section of this device takes in RF energy and puts out DC. There's no information content in DC. Just an indication of the RF input level that's proportional to the DC level. Once the signal is converted to DC, there's no way to extract any information about the modulated data signal. The current design is a blinky-light, and is a completely wasteful use of a microprocessor.

    Any future device that intends to interpret the information modulated onto the carrier will need a form of downconverter. I don't care what kind is implemented, but it's going to need to be a honest-to-ghod receiver. That's much more complicated than a simple peak detector. I'll be impressed when they put the receiver in there. Until then ... meh.

  6. Re:The One Ring! by Anonymous Coward · · Score: 2, Informative

    Yeah, but eventually the battery dies. And *that's* when you make your move.

    By the time that happens you're going to need a haircut, manicure, pedicure, a shower and shave, and probably a change of underwear.