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Detecting Life under rubble

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Wond3rboy

Member
Hi i have a question which is how does microwave detection under rubble works.These are used when earthquakes occur.I know it works by transmission and reflection but couldnt get a decent article on google on what is actually being done with the received signal since i want to do something similiar using uc.
 

KMoffett

Well-Known Member
Google: ground penetrating radar GPR

Ken
 

duffy

Well-Known Member
I think they just look for voids, don't they? Could they be used to detect a beating heart or struggling life by looking for characteristic accelerations in otherwise unmoving rubble?
 

Sceadwian

Banned
The most sophisticated device you can use for finding people under rubble is a dog =\
 

Willbe

New Member
Some detect EM radiation from a beating heart.

One problem with these situations is that crushed muscle tissue puts toxins in the blood so you may eventually die from poisons your own body generated.
 
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Sceadwian

Banned
Definitly not EM from the heart, the signal has to be amplified just to be picked up from direct contact.
 

Wond3rboy

Member
I think they just look for voids, don't they? Could they be used to detect a beating heart or struggling life by looking for characteristic accelerations in otherwise unmoving rubble?
Thats the thing i want to acheive.I did find artiles on the net saying that a beating heart changes the frequency of the Tx signal and that at the Rx side(eliminate any noise etc). It said that low frequency as well as High freq signals could be used.
 

duffy

Well-Known Member
Yes, seems like it must be Doppler-shift.

Low frequencies (like in the mhz region) are used in ground-penetrating radar because the higher frequencies reflect off the surface. This causes a loss of resolution, but there might be a way to interpret the phases of the recovered signal from an transmitter/receiver array to get useful 3D mappings.

You could use a color screen and put the Doppler-shifting parts in red or something to indicate movement. You could write a software filter that only detects periodic motion in a frequency range that corresponds to the range of human heartbeats.
 

Wond3rboy

Member
Thanks Duffy.I was just searching for a suitable GPR to see whether i could take the Transmitter and Receiver from there and do the processing and found that it costs 113USD(the cheapest one!).Wow!. I will really have to think about what am i doing.
 
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duffy

Well-Known Member
You found a GPR for $113? That's much less expensive than any I could find. Where did you see this?
 

Wond3rboy

Member
Appararently i was mistaken since it was a book with the same name SORRY! :(.

Is there a way one can aquire the transmitting and receving part of a gpr? Manipulating the info will be my job(very tough?yes) and also will 18F PIc micros do for transmitting the signal to my laptop?I will process it using matlab.

Thanks for your reply.
 

duffy

Well-Known Member
A cheap one was like ten grand.

I think you have to build your own, Wond3rboy. Also, you are going to need 3nanosecond resolution on your counter just to get the distance to a meter.
 

duffy

Well-Known Member
They can't use dogs because they are Muslim. If dog spit touches the victim, and the victim dies, he will burn in hellfire and damnation for all eternity.

You probably think I'm making this up...
 

duffy

Well-Known Member
Part of Pakistan is already under Islamic law, using dogs is sure to be something the government frowns upon.
 
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