·A “Bourdon Tube” is used in: PRESSURE SENSORS
1)CCD Camera?
A CCD (Charge Coupled Device) is an electronic sensor used in cameras to capture digital images
It converts light → electrical charge → digital data
Each pixel stores charge proportional to the light intensity, forming the image
Construction
CCD is based on a MOS (Metal–Oxide–Semiconductor) structure, not a simple pn junction
Main parts:
P-type semiconductor body
Thin silicon dioxide insulating layer
Array of gate electrodes
When a positive voltage is applied to the gate:
Holes are repelled → a depletion region is formed
Incoming photons generate photoelectrons in this region
Charges are shifted horizontally by changing gate voltages step by step until collected and amplified
Working
CCD electrodes are arranged in a 2D array at the focal plane of the camera
After exposure:
A charge pattern is formed on the CCD, matching the brightness of the image
Readout process:
Row-shifter circuit moves charges row by row vertically into horizontal registers
Pixel-shifter circuit moves charges pixel by pixel horizontally into a preamplifier
The 2D image is converted into a time-domain waveform
This waveform is digitized → processed → stored as the final image
Applications
Digital cameras and camcorders
Astronomy telescopes (high sensitivity to faint light)
Medical imaging (X-ray, microscopy)
Scientific instruments (spectroscopy, satellites)
2)CMOS Camera?
A CMOS (Complementary Metal–Oxide–Semiconductor) sensor is used in modern cameras to capture digital images
It works on the photoelectric effect: photons → electrons → voltage → digital signal
Unlike CCD, CMOS converts charge directly into voltage inside each pixel
Better Construction of CMOS Camera
Base structure: Built on CMOS technology (Complementary MOS transistors)
Pixel design: Each pixel contains:
Photodiode – converts incoming light (photons) into electrical charge
Reset transistor – clears the pixel before the next exposure
Amplifier transistor – boosts the weak signal from the photodiode
Select transistor – connects the pixel to the readout line when chosen
Array arrangement: Pixels are arranged in a 2D grid (rows and columns)
Row/column addressing: Transistors allow direct access to each pixel, so signals can be read individually
On-chip circuitry: Includes amplifiers, multiplexers, and often ADC (Analog-to-Digital Converter) integrated on the same chip.
Working
Light falls on the photodiode → electrons are generated
These electrons are converted into voltage directly at the pixel
Signals are multiplexed (row by row, column by column)
The DAC chip collects the signals → converts them into digital data
Result: fast image capture with high frame rates and good quality
Applications
Digital cameras, CCTV, video cameras (high resolution)
Industrial cameras (manufacturing, automation)
Automotive & aviation (guidance, range finding)
Healthcare & biomedical imaging
Astronomy & scientific instruments
3)Stereo Vision in AMR Robots?
Introduction
In healthcare and laboratories, robots must handle medicines and samples with great care
To do this safely, they need accurate perception of surroundings, similar to human vision
Stereo vision gives robots depth perception, helping them identify items correctly and avoid mistakes
Principle / Construction
Stereo vision copies how humans see with two eyes
Two cameras are placed side by side, each capturing the scene from a slightly different angle
By comparing these two images, the robot can calculate the distance and depth of objects
Careful calibration ensures the cameras are aligned for accurate results
Stereo systems can be:
Passive – use normal ambient light
Active – use extra light/projectors for better accuracy in low‑light or featureless scenes
Working
The robot’s computer compares the two camera images using triangulation (baseline distance + angles)
This creates a 3D depth map of the environment
The robot updates this map in real time as it moves
Depth perception allows robots to:
Recognize and classify objects (medicines, lab tools, samples)
Navigate safely, avoiding humans, equipment, or other robots
Adjust routes instantly if obstacles appear
Perform delicate tasks like transferring fragile samples or guiding surgical tools
Applications
Healthcare
Laboratories
Navigation
Industry & AR
4)Night Vision?
Introduction
Night vision allows us to see in very low light conditions
With proper equipment, a person can be seen even 200 yards away on a moonless night
It works using infrared light and special image‑processing technologies
Infrared Spectrum
Near‑IR: 0.7 – 1.3 microns, close to visible light
Mid‑IR: 1.3 – 3 microns, used in devices like remote controls
Thermal‑IR: 3 – 30+ microns, shows heat emitted by objects
Types of Night Vision
Image Enhancement
Collects small amounts of visible + near‑IR light
Amplifies it using an image‑intensifier tube
Photocathode converts photons → electrons
Microchannel plate multiplies electrons thousands of times
Electrons hit phosphor screen → green image
Viewed through ocular lens or display
Thermal Imaging
Detects heat (thermal‑IR) emitted by objects
Lens focuses IR light → detector array creates thermogram
Thermogram → electrical impulses → processed into image
Hotter objects appear brighter/colored differently
Applications
Military and law enforcement
Hunting and wildlife observation
Surveillance and security
Navigation in dark areas
Hidden‑object detection
Entertainment
5)Orifice Plate?
An orifice plate flow transducer works by placing a thin plate with a hole inside a pipe. When fluid flows through the hole, its speed increases and pressure drops. By measuring this pressure difference, the flow rate can be calculated.
A thin plate with a small hole (called an orifice) is fixed inside a pipe
Fluid (liquid or gas) must pass through this hole
The hole makes the fluid speed up as it squeezes through
According to Bernoulli’s principle, when speed increases, pressure decreases
Pressure before the plate (upstream) is higher
Pressure after the plate (downstream) is lower
This difference in pressure is directly linked to how fast the fluid is flowing
Pressure taps are placed before and after the orifice plate
A differential pressure sensor or manometer measures the pressure drop
The bigger the pressure drop, the higher the flow rate
Flow rate is proportional to the square root of the pressure difference
The orifice plate creates the pressure difference
The transducer converts this pressure difference into an electrical signal
That signal can be displayed or recorded as flow rate
Applications
Widely used in water supply, oil refineries, chemical plants, and gas pipelines
Simple, cheap, and reliable for measuring flow
6)Piezo Electric?
A piezoelectric actuator is a device that converts electrical energy into precise mechanical motion
It works on the piezoelectric effect, where certain materials change shape when voltage is applied
The movement is very small but highly accurate, making it ideal for nano‑scale positioning
They are valued for fast response time, high stiffness, and no need for lubrication or gears
Commonly used in industrial automation, robotics, medical devices, and scientific instruments
Advantages include compact size, reliability, and ability to operate in extreme environments
Limitations: small displacement range and need for high voltage drive circuits
Overall, piezo actuators are critical wherever precision, speed, and stability are required
7)Stepper Motor?
A stepper motor is an electromechanical device that converts digital pulses into mechanical rotation. It operates in a step‑by‑step manner, allowing precise control of position and speed without feedback systems.
The permanent magnet stepper motor works on the principle of magnetic attraction and repulsion between the stator windings and the rotor’s permanent magnets. When electrical pulses are applied to the stator windings in sequence, magnetic fields are created with defined north and south poles. The rotor aligns with these fields, producing controlled rotation.
Different modes of operation include:
Full‑step → one winding energized, rotor moves one full step angle
Half‑step → alternate energizing of windings, rotor moves half step angle for smoother motion
Micro‑stepping → unequal currents in windings divide steps into finer angles, giving very smooth rotation
Stepper motors are widely used in printers, CNC machines, robotics, and automation systems where accurate positioning is essential.
Conclusion:
Stepper motors are simple, reliable, and precise devices that convert electrical pulses into controlled mechanical movement, making them vital in modern automation and robotics.
8)DC Motor?
A Brushed DC Motor is one of the simplest and most widely used electric motors. It converts direct current (DC) electrical energy into mechanical rotation using brushes and a commutator.
Armature (Rotor): Rotating part with copper windings that produce magnetic field when current flows
Field Coil (Stator): Fixed windings or magnets that create the main magnetic field
Commutator: Copper segment that acts as a switch, reversing current direction in the armature
Brushes: Carbon blocks that transfer current from the external circuit to the rotating commutator
the field coil makes the magnetic field, the armature rotates, and the commutator + brushes keep current flowing between fixed and moving parts.
Working Principle
DC current energizes the stator, creating a magnetic field
The rotor windings interact with this field, causing rotation by attraction and repulsion
As the rotor aligns with the field, the commutator reverses current, ensuring continuous rotation
Applications
Brushed DC motors are still used in:
Cranes, conveyors, pumps, fans
Machine tools, air compressors
Toys and car motor starters
Conclusion
Brushed DC motors are simple, reliable, and cost‑effective, making them suitable for many industrial and everyday applications, even though modern brushless motors are replacing them in advanced systems.
9)Proximity Sensor ?
A proximity sensor is a device that detects the presence of an object without physical contact. It converts changes in a field (electrical, magnetic, or optical) into an electrical signal.
Principle of Working
Proximity sensors work on the principle of field disturbance
They generate a sensing field (electromagnetic, capacitive, or optical)
When an object enters this field, it changes the field characteristics
The sensor’s circuit detects this change and produces an output signal
Types & Operation
Inductive Sensors: Detect metallic objects by creating an electromagnetic field
Capacitive Sensors: Detect both metallic and non‑metallic objects by sensing changes in capacitance
Ultrasonic Sensors: Use sound waves; reflection from an object is measured
Photoelectric Sensors: Use light beams; interruption or reflection indicates presence
Applications
Used in automation systems for object detection
Robotics for obstacle sensing
Industrial machines for position control
Consumer devices like smartphones (screen on/off near ear)
Conclusion
Proximity sensors are contactless, reliable, and fast detectors that play a vital role in modern automation, robotics, and everyday electronics.
10)Illustrate the working principle of soppler effect?
Doppler Radar
A Doppler radar is a special type of radar system that measures the velocity of a moving object using the Doppler effect. The Doppler effect states that when a wave is reflected from a moving target, its frequency changes depending on the relative motion between the source and the target.
Principle of Working
The radar transmits microwave signals toward a target
When the signal hits a moving object, it is reflected back with a frequency shift
If the object is moving towards the radar, the reflected frequency increases
If the object is moving away, the reflected frequency decreases
The radar receiver measures this frequency difference, which is directly proportional to the speed of the target
Applications
Weather forecasting: Measuring wind speed and tracking storms
Aviation: Detecting aircraft speed and movement
Traffic control: Speed detection of vehicles
Military: Tracking enemy aircraft or missiles
Sports: Measuring ball or player speed
Conclusion
Doppler radar works by detecting the frequency shift of reflected waves to measure motion and speed. Its accuracy and reliability make it vital in meteorology, transportation, defense, and scientific research.
11)Illustrate The Working Principle Of Optical Triangulator Range Sensors?
An optical triangulation range sensor is a device used to measure the distance of an object using the principle of light reflection and geometry. It is widely used in robotics, automation, and industrial measurement systems for precise non‑contact distance sensing.
Principle of Working
A light source (usually a laser or LED) projects a beam onto the target object
The reflected light from the object is collected by a position‑sensitive detector (PSD) or camera lens system
Depending on the distance of the object, the reflected light falls at different positions on the detector
Using triangulation geometry, the sensor calculates the exact distance:
Closer object → reflection falls at one angle
Farther object → reflection shifts to another angle
Thus, the sensor converts the position of reflected light into a precise distance measurement
Applications
Robotics: Obstacle detection and navigation
Industrial automation: Positioning and quality inspection
Safety systems: Detecting presence of objects/people
Consumer devices: Used in cameras for autofocus
Conclusion
Optical triangulation sensors work by projecting light and measuring its reflected position to determine distance. They are accurate, fast, and reliable, making them essential in modern automation and robotics.
12)Hall Effect Sensor ?
A Hall Effect sensor is a transducer that detects the presence of a magnetic field and converts it into an electrical signal. It works on the Hall Effect principle, discovered by Edwin Hall in 1879.
Principle of Working
When a current‑carrying conductor or semiconductor is placed in a magnetic field, the moving charge carriers (electrons) experience a force.