sensores pirolicos

8/8/2019 sensores pirolicos

http://slidepdf.com/reader/full/sensores-pirolicos 1/12

INFRARED PARTS

MANUAL

PIR325

FL65

GLOLABCORPORATION



Thank you for buying our Pyroelectric Infrared components.

The goal of Glolab is to produce top quality electronic kits, products and components. All of ourkits are designed by Glolab engineers and tested in our laboratory. Mechanical devices,

prototypes and enclosures are fabricated in our precision machine shop.

Glolab Corporation has two locations in New York’s Hudson Valley. Our electronics laboratoryand kit packaging is located in Wappingers Falls and our machine shop is in Lagrangeville.

In addition to our kits, we supply some special and hard to find parts such as our PyroelectricInfrared Sensor, Infrared Fresnel lens and machined enclosure for mounting our Fresnel lens.for those of you who want to design and build your own projects.

Technical help is available by email from [email protected].

Copyright © 2003Glolab Corporation307 Pine Ridge DriveWappingers Falls, NY 12590

2



Infrared Radiation_____________

Infrared radiation exists in the electromagnetic spectrum at a wavelength that is longer thanvisible light. Infrared radiation cannot be seen but it can be detected. Objects that generate heat

also generate infrared radiation and those objects include animals and the human body whoseradiation is strongest at a wavelength of 9.4µm.

Pyroelectric Sensors_____________

The pyroelectric sensor is made of a crystalline material that generates a surface electric chargewhen exposed to heat in the form of infrared radiation. When the amount of radiation striking thecrystal changes, the amount of charge also changes and can then be measured with a sensitiveFET device built into the sensor. The sensor elements are sensitive to radiation over a widerange so a filter window is added to the TO5 package to limit incoming radiation to the 8 to

14µm range which is most sensitive to human body radiation.

Figure 1 shows how typically, the FET source terminal pin 2 connects through a pulldownresistor of about 100 K to ground and feeds into a two stage amplifier having signal conditioningcircuits. Each of the two cascaded stages has a gain of 100 for a total gain of about 10,000. Theamplifier is typically bandwidth limited to below 10Hz to reject high frequency noise and isfollowed by a window comparator that responds to both the positive and negative transitions ofthe sensor output signal. A well filtered power source of from 3 to 15 volts should be connectedto the FET drain terminal pin 1.

The PIR325 sensor has two sensing elements connected in a voltage bucking configuration.

This arrangement cancels signals caused by vibration, temperature changes and sunlight. Abody passing in front of the sensor will activate first one and then the other element as shown infigure 2 whereas other sources will affect both elements simultaneously and be cancelled. Theradiation source must pass across the sensor in a horizontal direction when sensor pins 1 and 2are on a horizontal plane so that the elements are sequentially exposed to the IR source.

Figure 3 shows the PIR325 electrical specifications and layout in its TO5 package. Please notethat the distance from the front of the sensing elements to the front of the filter window is 0.045inch (1.143mm). Figures 4 and 5 describe a Fresnel lens designed to be used with the PIR325sensor.

Figure 6 shows a typical application circuit that drives a relay. R10 and C6 adjust the amount oftime that RY1 remains closed after motion is detected. When used with a PIR325 sensor andFL65 Fresnel lens, this circuit can detect motion at a distance of up to 90 feet.

Figure 7 shows an application circuit that will indicate the direction that an infrared radiatingsource is moving.

3



PIR

FRESNEL LENS

THERMAL ENERGY

+V

OUTPUT

COMPARATORAMPLIFIER

IR FILTER

TYPICAL CONFIGURATION

FIGURE 1

FIGURE 2

FIGURE 2

4



PIR325 Infrared Pyroelectric Sensor

Specifications and Dimensions

PIR325ELEMENT SIZE 2 x 1, 2 elements

SPECTRAL RESPONSE µm (1) 5 ~ 14

NOISE µVpp 20

OUTPUT mv pp (2) 3900

OFFSET VOLTAGE volts (3) 1.0

SUPPLY VOLTAGE volts (4) 2.5 ~ 15

OPERATING TEMPERATURE ° C -30 ~ 70

STORAGE TEMPERATURE ° C -40 ~ 80

NOTES:1. With built-in window filter

2. After 72 db amplifier gain3. At source pin 2 with 5 volts and 100K load4. Well filtered power supply

1 drain

2 source

3 ground

3

2 1

BOTTOM VIEW

TOP VIEW

95o

8.3 + 0.2

IR window

4.5 + 0 _

_

_

3.5 + 1 _

0.45 x 3

3.4

4.6

9.2 + 0.2

_ 5.08 + 0.2

All dimensions are in millimeters

View Angle

1.0 1.0 1.0

2.0

1.143

FIGURE 3

5



Fresnel Lens_____________

A Fresnel lens is a Plano Convex lens that has been collapsed on itself as in figure 5 to form a

flat lens that retains its optical characteristics but is much smaller in thickness and therefore hasless absorption losses.

PLANO CONVEX FRESNEL

FIGURE 4

The FL65 Fresnel lens is made of an infrared transmitting material that has an IR transmission

range of 8 to 14 µm that is most sensitive to human body radiation. It is designed to have itsgrooves facing the IR sensing element so that a smooth surface is presented to the subject sideof the lens which is usually the outside of an enclosure that houses the sensor.

The lens element is round with a diameter of 1 inch and has a flange that is 1.5 inches square.This flange is used for mounting the lens in a suitable frame or enclosure. Mounting can bestand most easily be done with strips of Scotch tape. Silicone rubber adhesive can also be usedto form a more waterproof seal.

The FL65 has a focal length of 0.65 inches from the lens to the sensing element. It has beendetermined by experiment to have a field of view of approximately 10 degrees when used with aPIR325 Pyroelectric sensor. Figure 6 shows the lens dimensions.

6



PIR

FRESNELLENS

0.65"

install lens withgrooves facing PIR

1.1"1.5"

activearea

mountingborder

0.015" thickness

Optimum transmittance in the 8 to 14 um region

focal length

IR

FIGURE 5

7



General purpose motion detector_____________

This motion detector circuit uses a low cost LM324 quad operational amplifier as both a twostage amplifier and a window comparator. Amplifiers IC1A and IC1B have a gain of 100 each for

a total of about 10,000.

IC1C and IC1D form a window comparator that responds to signals about 200 millivolts aboveand 200 millivolts below Vcc/2. This window is set by the low current voltage drops across D1and D2. Comparator outputs feed through D3 and D4 that pass only the positive transitions intoCD4538 CMOS single shot IC2 which feeds into Q1 that drives relay RY1.

The R10 and C6 time constant determine how long the relay remains energized after motion isdetected. All components can operate on 5 to 12 volts. This type of circuit is often used to turna light on outside of a house when motion is detected.

+

+

+

_

_

_

+

+

PIR

MOTION DETECTOR

R1 10K

12

3 IC1A IC1B

IC1C

+

_

IC1D

R2

100K

R4 1 M

C3 .1 C5 .1

C2

C4

10D1

D2

+

R510K

R3

10K

R8 1M

R7

1M

R6

1M

D3

D4

IC2 =CD4538

RY1

C1

10

10

IC25

6

7

8 9

10

11

121

3

2

76

5

8

10

9

12

13 14

R10

C6

1

11

4

IC1 = LM324 PIR = PIR325

D1 - D5 = 1N914

R10 Kohms X C6 mfd = ON time ms

+5 - +12 VOLTS

µ f

µ fµ f

µ f

µ f

µ f

R9

1M

1

2

3

4 13

14

15

161M

R11 10K

10K

R12

D5

Q1

2N3904

CD4538

+

RY1 - coil voltage rating = V+ voltage

APPLICATION CIRCUIT FIGURE 6

8



Direction sensing motion detector_____________

This motion detector circuit will both detect motion and indicate the direction that an infraredemitting body is moving. The amplifier and comparator circuits are similar to those in figure 6.

Potentiometer R10 is a sensitivity adjustment to vary the detection range.

IC2 is a CD4538 dual single shot. The first single shot to receive a trigger input from IC1C orIC1D will turn its output on to indicate the direction of detection and will also inhibit the othersingle shot so that it cannot be triggered while the first single shot is on. Potentiometer R15adjusts the amount of time that an output remains on after motion is detected.

This type of motion detector can be used to indicate people entering or leaving a building or insome robotic applications.

+

+

+

_

_

_

+

+

R2 10K

12

3

IC1A IC1B

IC1C

+

_

IC1D

R1100K

R4 1M

C7

C6 .1

C3

C5

10

+

R5

10K

R3

10K

R10 1M

R9

2M

R6

2M

IC2 = CD4538

C2

10

10

IC2

5 6 7 8

9101112

1

3

2

1413

12

8

10

9

5

67

11

4

IC1 = LP324PIR = PIR325

+5 VOLTS

µ f

µ f

µ f

µ f

µ f

1 2 3 4

13141516

R15

1M

C4 .1

10 µ f

LEF

RIGH

+

+7 - 15

IC3C10

µ f10

IC3 = S-812C50AY-B

GROUN

Q1

Q2

VDC _

PIR

C1100

pf

R7

300K

R8

300K

C9

µ f.1

R14

10K

R11 100K

D3

D1,D2,D3 = 1N914 Q1, Q2 = 2N7000

R12 100K

R13 100K

D1

D2

APPLICATION CIRCUIT FIGURE 7

9



10



11



GLOLABCORPORATION

307 Pine Ridge DriveWappingers Falls, NY 12590voice - (845) 297-9771

Fax - (845) 297-9772Email - [email protected]://www.glolab.com

© 2003 Glolab Corp.

12

sensores pirolicos

Documents