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Destination Tomorrow - DT2 - Sensors

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Destination Tomorrow Segment describing sensor technology and explains what they are and how they work.

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Ground and wind tunnel testing are currently underway in the morphing program to bring 00:00:00
these fascinating technologies to fruition. 00:00:04
Sensor technologies have been around for quite some time. 00:00:08
In fact, sensors are virtually everywhere. 00:00:10
But what are they? 00:00:13
And how do they work? 00:00:14
For some answers, we turn to Johnny Alonzo. 00:00:15
Sensors, sensors, sensors. 00:00:20
They're just about everywhere. 00:00:26
Most people probably couldn't live without them. 00:00:28
Have you ever slammed a snooze bar on your alarm, opened your garage with a remote control, 00:00:30
set your car alarm, or changed the channels on your television with a remote? 00:00:34
Sure you have. 00:00:39
They're all controlled by sensors. 00:00:40
With today's technology, most sensors are extremely small or invisible to the naked 00:00:42
eye. 00:00:46
Heat, light, sound, pressure, or a particular motion can trigger a sensor to perform a specific 00:00:47
action. 00:00:54
There are sensors in our cars, our homes, offices, even in our own bodies. 00:00:55
But what exactly is a sensor? 00:01:00
And how does it work? 00:01:02
For some answers, I spoke with Dr. Gary Gibbs at NASA Langley Research Center. 00:01:04
A sensor is a device that detects physical phenomena such as light, heat, air flow, pressure, 00:01:08
temperature, even sound. 00:01:14
And generally speaking, how do sensors work? 00:01:16
They work through a mechanism called transduction, where we're converting one form of energy 00:01:18
into another. 00:01:22
A transduction may be a form of energy that's less useful than, say, electrical energy. 00:01:23
And an example would be like a solar cell, where it takes energy from the sun and converts 00:01:27
it into electrical energy that we can use. 00:01:31
All sensors utilize transduction to convert energy such as light or heat into typically 00:01:34
electrical energy. 00:01:38
Another example might be a telephone button, which when pressed converts mechanical energy 00:01:39
from your finger into an electrical signal in the form of a tone. 00:01:44
So Gary, what are some typical examples of sensors that we use every day? 00:01:49
Sensors are around us everywhere. 00:01:52
In fact, when we go to the grocery store, there's barcode scanners to detect the barcodes 00:01:53
of products we buy. 00:01:58
In fact, in our car, there's sensors to detect a crash, to open airbags. 00:01:59
In fact, the telephones that we use every day have sensors called microphones that sense 00:02:04
the sound of our voice. 00:02:08
So it would be safe to say that there are millions of sensors out there, right? 00:02:10
Absolutely. 00:02:14
Really? 00:02:15
Do they all work the same? 00:02:16
No, they actually work quite differently. 00:02:17
We've got quite a few examples of microphones today, and they were designed for different 00:02:18
reasons. 00:02:21
Okay. 00:02:22
In fact, the first item we see here is an ancient telephone from the 50s. 00:02:23
I love it. 00:02:26
And you can see here a typical microphone from a CB radio or intercom type system. 00:02:27
Sure. 00:02:33
In fact, this is a microphone like you might see on your home computer, and we have a cell 00:02:34
phone here that even has a very tiny microphone that senses the sound of your voice. 00:02:37
And they all sense the same kind of phenomenon, but each one is designed specifically for 00:02:42
a particular purpose. 00:02:46
They're all configured quite differently. 00:02:47
So a microphone is a sensor? 00:02:50
Yes. 00:02:52
Okay. 00:02:53
So how does a microphone sense sound? 00:02:54
Well, we have a laboratory-grade microphone here connected to an oscilloscope, which is 00:02:55
a device that shows the electrical signal produced by the microphone. 00:02:59
And you can see when I whistle, it displays a sine wave. 00:03:03
A microphone is constructed with two plates, one thick and one thin, and the sound from 00:03:08
our voice, for example, strikes the thin plate, causing it to vibrate. 00:03:13
That vibration produces an electrical signal similar to what we saw in the oscilloscope. 00:03:17
Okay. 00:03:21
So earlier I mentioned biological similarities between sensors and human senses. 00:03:22
Right. 00:03:27
Okay. 00:03:28
How is a microphone similar to the human ear? 00:03:29
That's pretty interesting because sound travels through the ear until it strikes the eardrum, 00:03:30
causing it to vibrate, similar to the plates in the microphone we talked about earlier. 00:03:35
This vibration is transferred through tiny bones to the cochlea, which contains small 00:03:39
hair follicles that vibrate, producing an electrical impulse similar to the microphone. 00:03:45
So the hair follicles are like sensors. 00:03:50
Yes. 00:03:52
Well, Gary, thanks for your time and for showing us how sensors work. 00:03:53
Sure. 00:03:55
Thanks for coming out to the National Atlantic Research Center. 00:03:56
No problem, man. 00:03:57
No problem. 00:03:58
I guess that's a wrap. 00:03:59
Hey, is this thing still on? 00:04:00
Sure. 00:04:01
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Idioma/s:
en
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
617
Fecha:
28 de mayo de 2007 - 17:04
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
04′ 03″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
23.58 MBytes

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