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2.4GHz Wi-Fi Detector Ring Project
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."
The maximum detection range appeared to be roughly 40 feet (line of sight), which is not exactly great, but this can likely be blamed on the antenna...
He doesn't mind
However, who would want to detect a Wi-Fi if he's not going to use it? If you're already a mobile user, it might be easier to just use your device's auto-detection software.
I agree that there are times when I wish I could have detected the signal before I take out my laptop, but I usually solve that problem by starting up my PDA first.
Rock that crushes, Paper & Scissors that don't matter.
The designers should consider making this a watch instead of a ring. That way they can also design a UI for the watch's display, and you would have more room for bulk on your wrist than on your finger.
from TFA: ...the prototype unit does not discriminate between other sources of 2.4GHz RF, eg. "leaky" microwave ovens,...
So it will keep me from cooking my cohones along with my microwave popcorn...that sounds useful to me. If the Atmel could be programmed to drive a little active antenna tuning, maybe it would also double as a bug sweeper?
Disclosure: I do wear a pocket protector.
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
Why don't they invent one even more useful to: ... Detect when a woman has had enough to drink and will sleep with almost anyone
Liability, probably. Sex with someone who is not able to give consent is rape. Legally (though IANAL), a woman who's had enough to drink so she'll sleep with anyone is not sober enough to give consent.
The only surefire protection against Microsoft infections is abstinence. - The Onion
Actually, you might discover (through experimentation, or whatever) that inserting a processor in-line with an 'LED flasher' circuit can actually save significant power over just blinking the LED itself.
This is due to some esoteric details of how an LED is most efficiently driven. I learned when I was developing firmware for some small hand-held medical devices that used a Microcontroller (an NEC 4-bit controller) that you can actually get greater efficiency (more light output per power consumed) by driving LEDs with a VERY high current for a very short duty. Drive them to 100 mA or so at a 1% duty cycle, for starters, and experiment with high drive current and duty cycle. There is a dramatic current savings over driving an LED with a DC level to get equivalent brightness.
The power saving achived by this means will likely be more than enough to power the processor, if it's one of the tiny micro-power processors. Use one of the little 8 pin PIC parts or what-not.
There- interesting (hopefully) topic drift.
"What's the frequency Kenneth?"