Extremely useful knowledge

[Checkpoint]

What if they steal your car keys and then chop off your hand? They'd be violent people, that's all.

[Krookie]

You know what guys? How about you all just stop losing your keys, and we can forget about the whole "fingerprint, eye scanner, stab you in the heart to see if your blood type matches the one on file" discussion.

[Hurlshort]

Our first trial didn't work, but we have a pretty bad connection where we live. I'll try it later today with better cell phone coverage.

[taks]

sorry folks, but cell phones don't work the way you think...

 

first, high frequencies such as what meta pointed out cannot be transmitted over a cell phone. nor can infrared or standard EM from a radio transmitter.

 

the technical reasons are detailed, but in short, a cell phone does not actually transmit your voice! actually, they employ what are known as vocoders, which interpret your voice and translate the various parameters into symbols. they can function as low as a few kbits/s (i believe they actually run at 14.4 kHz typically, but transmit only what is required). the highest frequency that can reasonably make it through a cell phone is in the 3-5 kHz range (which explains why children are very hard to understand on a cell). also, this is why cells don't work well with a large amount of background noise (particularly in a noisy bar).

 

taks

Edited August 27, 2006 by taks

[Calax]

another piece of useful knowledge... always know how to break into your own home. (I've locked myself out and done it about six or seven times.

[metadigital]

Yeah, but your home is easy to break into.

[Checkpoint]

Yeah, but your home is easy to break into.

<{POST_SNAPBACK}>

Quoted for truth. :D

[Calax]

Yeah, but your home is easy to break into.

<{POST_SNAPBACK}>

Quoted for truth. :D

<{POST_SNAPBACK}>

requires a ladder at least...

[Checkpoint]

Oh, tell me about it...

 

*bends back in agony*

[Petay]

Haha! :D

 

An easier way to bypass that old problem is to hide a key in your backyard...

 

And now I'm quickly thinking about totally liek removing myself from Frappr.

[Krookie]

An easier way to bypass that old problem is to hide a key in your backyard...

<{POST_SNAPBACK}>

 

Of course. Cause when you're stranded in a parking lot 84 miles away from your house, you can just waltz right over to the rock in your backyard, pick up the key, and waltz right on back!

[Petay]

Of course. Cause when you're stranded in a parking lot 84 miles away from your house, you can just waltz right over to the rock in your backyard, pick up the key, and waltz right on back! 

<{POST_SNAPBACK}>

 

Seems it wasn't clear to some about what I was replying to.

 

another piece of useful knowledge... always know how to break into your own home. (I've locked myself out and done it about six or seven times.

<{POST_SNAPBACK}>

[Krookie]

I accept your apology, then.

[Craigboy2]

sorry folks, but cell phones don't work the way you think...

 

first, high frequencies such as what meta pointed out cannot be transmitted over a cell phone.  nor can infrared or standard EM from a radio transmitter.

 

the technical reasons are detailed, but in short, a cell phone does not actually transmit your voice!  actually, they employ what are known as vocoders, which interpret your voice and translate the various parameters into symbols.  they can function as low as a few kbits/s (i believe they actually run at 14.4 kHz typically, but transmit only what is required).  the highest frequency that can reasonably make it through a cell phone is in the 3-5 kHz range (which explains why children are very hard to understand on a cell).  also, this is why cells don't work well with a large amount of background noise (particularly in a noisy bar).

 

taks

<{POST_SNAPBACK}>

I always thought it was just magic.

[taks]

I always thought it was just magic. 

<{POST_SNAPBACK}>

any sufficiently advanced technology appears as magic to those that have not seen it before.

 

a description of how the data is actually, sent, btw, is even cooler (read: more magical).

 

taks

[Atreides]

Dudes talk about the yakuza. Mythbusters 3x22 handles beating security systems and the fingerprint tech (basic tech and ones with "live" tech/pulse, heat, sweat etc), sonar and thermal. Plus they filled a safe and set off a depth charge in it to try to blow the door out (spoiler: they did MWAHAHHAHAA).

 

Anyway they beat the "live" fingerprint tech with 3 different techniques.

a. Latex imprint stuck on thumb

b. Silicon imprint

c. Photocopied thumbprint on paper

 

I'll be sure to let them yakuza know about that when they're after my fingers. USO DA.

[Fenghuang]

Were they using sub-dermal scanners?

[Atreides]

They didn't mention.

[Judge Hades]

I tend to leave my door unlocked.

[Checkpoint]

For which I'm eternally grateful (damn Calax and his stupid ladder).

[Gfted1]

You know how your car remote has a certain range? Well, my friend firmly believes that if you hold the remote under your chin while you use it you can extend the range. After I got done laughing I asked why he thought that and it had something to do with the fillings in your teeth somehow amplifying the signal. I keep meaning to try my remote start from inside a mall or something but keep forgetting.

[taks]

my knowledge of antennas, while not to the level of an expert, tells me your friend's assertion is incorrect.

 

it is impossible to passively amplify a signal (i.e. you need a power source), however, it is possible to sort of "channel" the signal, i.e. focus it in a specific direction (the basis of what i actually do for a living). if your friend IS correct that he can increase the range, this would be the likely candidate for why it is working.

 

taks

[Gfted1]

Perhaps you make your entire body an antenna? Kinda like how when we had rabbit ears on our TV's the channel would always look better while you were physically holding the antenna?

[metadigital]

I've done it. (Extended the range of the remote using my head, that is.)

 

Also, my friend used to use nearby (all metal) street lights to give his remote electronic car lock super-range.

 

[taks]

all antennae have an associated gain, which should not be confused with amplification. they are usually listed in terms of dBi (dB incident). this is probably what you guys are seeing. i.e. your body (or street lights) are acting as an antenna with a somewhat focused beampattern. if that beampattern is omni-directional (i.e. radiates in all directions equally), the gain is 0 dBi, or no apparent gain. directional antennae, which is probably the effect you guys are seeing, have a gain that is a ratio of the surface area of a unit sphere to the relative area of the beam on that sphere.

 

interesting effect sans technical jargon nonetheless.

 

taks