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DIFFERENT TYPES OF SENSORS AND THEIR A PPLICATIONS

Group Members :

Naveed Arshed (BEE-FA08-019)

Haider Abbas (BEE-FA08-044)

Gulfam Jamil (BEE-FA08-041)

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SENSORS:

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W HAT IS SENSOR A sensor is a device that measures a physicalquantity and converts it into a signal which can beread by an observer or by an instrument.

A device that measures or detects a real-worldcondition, such as motion, heat or light andconverts the condition into an analog or digitalrepresentation..

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SENSORS Example:

An optical sensor detects the intensity or brightness

of light, or the intensity of red, green and blue for color systems.

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USES OF SENSORS

Sensors are used in everyday objects such as

touch-sensitive elevator buttons and lamps whichdim or brighten by touching the base.

Applications include cars, machines, aerospace,medicine, manufacturing and robotics.

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T YPES OF SENSORS :

Metal Detectors

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METAL DETECTOR An electronic device used specifically for thedetection of buried metal objects

Metal detectors use electromagnetic induction to detect metal .

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HAND-HELD METAL DETECTOR :

Hand-held metal detectors are most commonly

used for body searches for weapons in crowdcontrol, and checking parcels and letters.

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W ORKING OF METAL DETECTOR

When hand-held detectors are switched on, a redsignal pattern in transmitted from the coil to theground.

When the signal comes in contact with a metal, itinterrupts the signal and the detector alerts the user with an audio signal and flashing lights.

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METAL DETECTORS :

Benefits and features

Hand-held Metal Detectors are designed tosafeguard security-sensitive areas like schools,sports events, businesses.They are cheaper and radiation-free, are usually

lightweight, highly sensitive and require littlemaintenance.

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T YPE OF SENSOR :

touch sensors

A touch sensor or touch switch is a type of switchthat only has to be touched by an object to operate.It is used in wall switches that also be used incomputer terminals.

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TYPES OF TOUCH SENSORS :

There are two types of switches called touchswitches:

Capacitance touch switch :

A capacitance switch needs only one electrode tofunction. The electrode can be placed behind a

non-conductive panel made of for example wood,glass or plastic.

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TYPES OF TOUCH SENSORS

Working: A capacitance touch switch works

using the property of the human body that gives it

great electrical characteristics. When a persontouches it, it increases the capacitance and triggersthe switch.Capacitance switches are available commerciallyas integrated circuits from among others .

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TYPES OF TOUCH SWITCH :

Resistance touch switch : A resistance switch needs two electrodes to be

physically in contact with something electricallyconductive (for example a finger) to operate.

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WORKING :

A resistance touch switch works by lowering theresistance between two pieces of metal. Placingone or two fingers across the plates achieves a turnon or closed state. Removing the finger from themetal pieces turns the device off.

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RADAR GUN

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RADAR GUN What is radar gun:

It is also a type of sensor. It is also called speed

sensor.

A radar gun is a small Doppler radar unit used todetect the speed of objects .

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BASIC PRINCIPLE OF RADAR GUN

IT depends on the Doppler Effect applied to a

radar beam to measure the speed of objects atwhich it is pointed.

EXAMPLES:

Radar guns may be hand-held or vehicle-mounted.

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Hand held Radar Gun Vehicle mounted Radar Gun

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DOPPLER EFFECT A change in the observed frequency of awave, as of sound or light, occurring whenthe source and observer are in motionrelative to each other, with the frequencyincreasing when the source and observer approach each other and decreasing whenthey move apart. The motion of the sourcecauses a real shift in frequency of the wave,

while the motion of the observer producesonly an apparent shift in frequency. Alsocalled Doppler shift .

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WORKING OF RADAR GUN

Radar guns are, in their most simple form are, radiotransmitters and receivers. . They send out a radiosignal, then receive the same signal back as it bouncesoff the objects.

Radar works by emitting invisible electromagneticwaves at a certain frequency, rather than visiblelight.

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WORKING OF RADAR GUN

When waves bounce back to the gun ,then Doppler shift occurs which is detected through which speedof object is calculated.

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PROBLEMS WITH RADAR GUNS

1: The object whose speed is desired ideallyshould be the only moving object in the beam of theradar.

2: The angle in which the object is in relation to theradar source can also affect the reading.

Interference in the RADAR band by cellular phones,power wires, high tension wires, signs and caneffect the readings.

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BEAM SENSOR

Light Beams, also known as Photo Eyes. Thesesensors detect the presence of a person or objectthat interrupts the light beam by passing through itspath.

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WORKING

Light beams use a transmitter/receiver system tosend an invisible or infrared light beam through theair along a desired path.

When the beam is interrupted, a signal is sent tothe internal relay, which is wired into the devicecontrols.

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USES

it is uses for security purpose in defensive areas.

It is also uses in checking the defected parts inmachines .