1
00:00:00,000 --> 00:00:04,940
Ground and wind tunnel testing are currently underway in the morphing program to bring

2
00:00:04,940 --> 00:00:08,560
these fascinating technologies to fruition.

3
00:00:08,560 --> 00:00:10,760
Sensor technologies have been around for quite some time.

4
00:00:10,760 --> 00:00:13,640
In fact, sensors are virtually everywhere.

5
00:00:13,640 --> 00:00:14,640
But what are they?

6
00:00:14,640 --> 00:00:15,640
And how do they work?

7
00:00:15,640 --> 00:00:20,240
For some answers, we turn to Johnny Alonzo.

8
00:00:20,240 --> 00:00:26,520
Sensors, sensors, sensors.

9
00:00:26,520 --> 00:00:28,320
They're just about everywhere.

10
00:00:28,320 --> 00:00:30,000
Most people probably couldn't live without them.

11
00:00:30,000 --> 00:00:34,960
Have you ever slammed a snooze bar on your alarm, opened your garage with a remote control,

12
00:00:34,960 --> 00:00:39,120
set your car alarm, or changed the channels on your television with a remote?

13
00:00:39,120 --> 00:00:40,320
Sure you have.

14
00:00:40,320 --> 00:00:42,440
They're all controlled by sensors.

15
00:00:42,440 --> 00:00:46,520
With today's technology, most sensors are extremely small or invisible to the naked

16
00:00:46,520 --> 00:00:47,520
eye.

17
00:00:47,520 --> 00:00:54,080
Heat, light, sound, pressure, or a particular motion can trigger a sensor to perform a specific

18
00:00:54,080 --> 00:00:55,080
action.

19
00:00:55,080 --> 00:01:00,040
There are sensors in our cars, our homes, offices, even in our own bodies.

20
00:01:00,040 --> 00:01:02,520
But what exactly is a sensor?

21
00:01:02,520 --> 00:01:04,120
And how does it work?

22
00:01:04,120 --> 00:01:08,320
For some answers, I spoke with Dr. Gary Gibbs at NASA Langley Research Center.

23
00:01:08,320 --> 00:01:14,360
A sensor is a device that detects physical phenomena such as light, heat, air flow, pressure,

24
00:01:14,360 --> 00:01:16,200
temperature, even sound.

25
00:01:16,200 --> 00:01:18,440
And generally speaking, how do sensors work?

26
00:01:18,440 --> 00:01:22,360
They work through a mechanism called transduction, where we're converting one form of energy

27
00:01:22,360 --> 00:01:23,360
into another.

28
00:01:23,360 --> 00:01:27,640
A transduction may be a form of energy that's less useful than, say, electrical energy.

29
00:01:27,640 --> 00:01:31,960
And an example would be like a solar cell, where it takes energy from the sun and converts

30
00:01:31,960 --> 00:01:34,080
it into electrical energy that we can use.

31
00:01:34,080 --> 00:01:38,800
All sensors utilize transduction to convert energy such as light or heat into typically

32
00:01:38,800 --> 00:01:39,960
electrical energy.

33
00:01:39,960 --> 00:01:44,320
Another example might be a telephone button, which when pressed converts mechanical energy

34
00:01:44,320 --> 00:01:49,080
from your finger into an electrical signal in the form of a tone.

35
00:01:49,080 --> 00:01:52,820
So Gary, what are some typical examples of sensors that we use every day?

36
00:01:52,820 --> 00:01:53,820
Sensors are around us everywhere.

37
00:01:53,820 --> 00:01:58,060
In fact, when we go to the grocery store, there's barcode scanners to detect the barcodes

38
00:01:58,060 --> 00:01:59,060
of products we buy.

39
00:01:59,060 --> 00:02:04,100
In fact, in our car, there's sensors to detect a crash, to open airbags.

40
00:02:04,100 --> 00:02:08,980
In fact, the telephones that we use every day have sensors called microphones that sense

41
00:02:08,980 --> 00:02:10,180
the sound of our voice.

42
00:02:10,180 --> 00:02:14,260
So it would be safe to say that there are millions of sensors out there, right?

43
00:02:14,260 --> 00:02:15,260
Absolutely.

44
00:02:15,260 --> 00:02:16,260
Really?

45
00:02:16,260 --> 00:02:17,260
Do they all work the same?

46
00:02:17,260 --> 00:02:18,260
No, they actually work quite differently.

47
00:02:18,260 --> 00:02:21,860
We've got quite a few examples of microphones today, and they were designed for different

48
00:02:21,860 --> 00:02:22,860
reasons.

49
00:02:22,860 --> 00:02:23,860
Okay.

50
00:02:23,860 --> 00:02:26,300
In fact, the first item we see here is an ancient telephone from the 50s.

51
00:02:26,300 --> 00:02:27,300
I love it.

52
00:02:27,300 --> 00:02:33,340
And you can see here a typical microphone from a CB radio or intercom type system.

53
00:02:33,340 --> 00:02:34,340
Sure.

54
00:02:34,340 --> 00:02:37,700
In fact, this is a microphone like you might see on your home computer, and we have a cell

55
00:02:37,700 --> 00:02:42,460
phone here that even has a very tiny microphone that senses the sound of your voice.

56
00:02:42,460 --> 00:02:46,540
And they all sense the same kind of phenomenon, but each one is designed specifically for

57
00:02:46,540 --> 00:02:47,980
a particular purpose.

58
00:02:47,980 --> 00:02:50,600
They're all configured quite differently.

59
00:02:50,600 --> 00:02:52,120
So a microphone is a sensor?

60
00:02:52,120 --> 00:02:53,120
Yes.

61
00:02:53,120 --> 00:02:54,120
Okay.

62
00:02:54,120 --> 00:02:55,120
So how does a microphone sense sound?

63
00:02:55,120 --> 00:02:59,520
Well, we have a laboratory-grade microphone here connected to an oscilloscope, which is

64
00:02:59,520 --> 00:03:03,760
a device that shows the electrical signal produced by the microphone.

65
00:03:03,760 --> 00:03:08,920
And you can see when I whistle, it displays a sine wave.

66
00:03:08,920 --> 00:03:13,200
A microphone is constructed with two plates, one thick and one thin, and the sound from

67
00:03:13,200 --> 00:03:17,840
our voice, for example, strikes the thin plate, causing it to vibrate.

68
00:03:17,840 --> 00:03:21,560
That vibration produces an electrical signal similar to what we saw in the oscilloscope.

69
00:03:21,560 --> 00:03:22,560
Okay.

70
00:03:22,560 --> 00:03:27,040
So earlier I mentioned biological similarities between sensors and human senses.

71
00:03:27,040 --> 00:03:28,040
Right.

72
00:03:28,040 --> 00:03:29,040
Okay.

73
00:03:29,040 --> 00:03:30,040
How is a microphone similar to the human ear?

74
00:03:30,040 --> 00:03:35,160
That's pretty interesting because sound travels through the ear until it strikes the eardrum,

75
00:03:35,160 --> 00:03:39,720
causing it to vibrate, similar to the plates in the microphone we talked about earlier.

76
00:03:39,720 --> 00:03:45,320
This vibration is transferred through tiny bones to the cochlea, which contains small

77
00:03:45,320 --> 00:03:50,560
hair follicles that vibrate, producing an electrical impulse similar to the microphone.

78
00:03:50,560 --> 00:03:52,320
So the hair follicles are like sensors.

79
00:03:52,320 --> 00:03:53,320
Yes.

80
00:03:53,320 --> 00:03:55,560
Well, Gary, thanks for your time and for showing us how sensors work.

81
00:03:55,560 --> 00:03:56,560
Sure.

82
00:03:56,560 --> 00:03:57,560
Thanks for coming out to the National Atlantic Research Center.

83
00:03:57,560 --> 00:03:58,560
No problem, man.

84
00:03:58,560 --> 00:03:59,560
No problem.

85
00:03:59,560 --> 00:04:00,560
I guess that's a wrap.

86
00:04:00,560 --> 00:04:01,560
Hey, is this thing still on?

87
00:04:01,560 --> 00:04:02,560
Sure.

88
00:04:02,560 --> 00:04:02,560