Ultrasonic Sensor-Electronics Seminar Topic:

Seminar on Ultrasonic Devices need Following Things.

• What is Sensor?
• Ultrasonic Waves?
• Properties.
• Principle and Working of Ultrasonic Devices.
• Applications.
• Explanation of some applications.

Some applications of Ultrasonics are as Below:

1. Ultrasonic Level Sensor.
2. Ultrasonic Distance Sensor.
3. Ultrasonic Flow Meters.

Sensors:

Sensor is Transducer Device which can sense the change in Pressure, Temperature etc. physical Quantities and turn them into readable digital or analogue quantity. Sensors are responsible for making simple devices and machines into SMART DEVICES or Machines.

What are Ultrasonic Waves?

Now, we discuss about Ultrasonic Devices. Here are some of major properties of Ultrasonic Waves.

1. First of all, Ultrasonic Waves are not the Electromagnetic Waves. They are mechanical waves.
2. As being the mechanical waves, they need medium for their propagation.
3. Their frequency is > 20kHz.
4. As high frequency, wavelength is ought to be small.
5. High penetrative properties.

Ultrasonic Sensors:

Ultrasonic Sensors generates high frequency sound waves and evaluates the echo which is received back by the sensor. They typically comprises at least one ultrasonic transducer which transforms electrical energy into sound and, in reverse, sound into electrical energy. An ultrasonic transducer consists of a transmitter, a receiver & a processing unit. It generates frequency range of 30kHz-100kHz.

Principle of Working For Ultrasonic Sensor:

1. Transducer typically have a piezoelectric ceramic element (material) that converts an excitation electrical signal into ultrasonic energy bursts or vibrations at very high frequency.
2. Conversely, generates voltage whenever subjected to vibrations.
3. Piezoelectric ceramic element such as lead-zirconate-titanate (PZT) having operating frequency close to 32kHz.

Applications:

1. Detecting and identifying solid objects.
2. Measuring the shape and orientation of a work-piece.
3. Distance measurement.
4. Room surveillance.
5. Flow measurement.
6. Level measurement of a tank.

Related Topics and Articles:

1. Ultrasonic Distance Sensing
2. Ultrasonic Level Sensor
3. Ultrasonic Flowmeters

Ultrasonic Flowmeters:

Already we have seen some of the ultrasonic devices before like Ultrasonic Level Sensor and Ultrasonic Distance Sensing. Now, I am going to explain one more ultrasonic device here. Ultrasonic Flow-meters are used to detect the speed of flow or subsequently quantity passed through the flow in given time.

Types of Ultrasonic Flowmeter:

1. Transit Time Type.
2. Doppler Frequency Shift Type.

1. Transit Time Type Ultrasonic Flowmeters:

In this type, two sensors are mounted on the pipe or channel. They send and receive the ultrasonic pulses simultaneously. When the speed of flow is zero or flow is steady, both the sensors receive the reflected pulses at the same time. Vice versa, when the fluid is in motion, sensors receive the pulse with delay between them. This delay is called as transit time difference. This transit time difference is directly proportional to velocity of flow and hence the volume of flow per unit time.

2. Doppler Frequency Shift Method:

Doppler effect could be explained as the frequencies of received sound waves depends on the motion of the source or observer relative to the propagating medium. The transmitter transmits ultrasonic waves. These are reflected from particles and bubbles. Frequency shifting takes place in reflected wave which is linearly proportional to the rate of flow of materials.

Advantages:

1. The flow of pure water, wash water, sewage, process liquids, oils, and other light homogeneous liquids can be measured.
2. It have no moving parts and hence have very less or no maintenance.
3. Can be used for variety of pipes.
4. It have flexibility to be used on existing pipelines.
5. It can be used as a portable device.
6. It does not have any contact with liquid and hence no danger from corrosive liquids.

Seminar on Ultrasonic Flow meter:

Above is given the information about ultrasonic flow meters. Here are short framework for seminar on ultrasonic flowmeter.

1. Introduction to Ultrasonics.
2. Ultrasonics Properties.
3. Ultrasonic Flowmeter.
4. Construction and working.
5. Types.
6. Transit time type.
7. Doppler Frequency Shift Method.
8. Advantages.
9. Limitations.
10. Applications.

Related Topics and Articles:

1. Ultrasonic Devices
2. Ultrasonic Distance Sensing
3. Ultrasonic Level Sensor

Introduction:

In previous article, we studied the Ultrasonic Level Sensors and its details. Now, I am going to explain the another ultrasonic device which works almost similar way to before. Ultrasonic Distance Sensor.

Ultrasonic Distance Sensing:

Ultrasonic Sensors are devices used to take measurements of Remote Distances or we call it as remote distance sensing. Ultrasonic sensing is based on time of flight principle. The transmitter produces the ultrasonic sound or burst or noise, which travels away from source and it enconters the barriers it gets reflected back. Then it is received by receiver.

Whole important topic here is Time Between Wave Produced and Wave Received. This time is used to calculate the distance between the ultrasonic device and obstruction. Other some constants like speed of ultrasonic sound in the air, humidity etc. are major factors in this calculation. If there is a relative movement between the source and the reflector, Doppler Effect can be employed to measure the distance.

Principle of Working of Ultrasonic Distance Sensor:

Ultrasonic sensors work on a principle similar to radar or SONAR which evaluate attributes of a target by interpreting the echoes from radio or sound waves respectively. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the echo to determine the distance to an object.

Formula For Ultrasonic Device Measurement:

d=(vt cos θ)/2

where;

d = Final distance,

t= time,

θ = angle of incidence,

Advantages:

1. Ultrasonic Distance measurement devices are more efficient.
2. Ultrasonic Distance measurement devices produce reliable accuracy.
3. Ultrasonic Distance measurement devices have robust construction and have long life of operation.
4. Ultrasonic Distance measurement devices have better accuracy than the other remote distance measuring devices.
5. Ultrasonic Distance measurement devices produce results faster than other devices.
6. Most important thing about Ultrasonic Distance measurement devices is that, they can produce result without interfering the object.

Disadvantages:

1. Ultrasonic Distance measurement devices have limitations when there is density of matter or medium is not consistant.
2. Also the reading may get distorted due to shapes of solids to be measured as reflection of ultrasonic wave is mostly dependent on shape of solid object which is treated as obstruction.

Applications:

Ultrasonic Distance measurement devices have many applications of which most popular are SONAR, Submarine Signaling, robotics etc.

Ultrasonic Distance measurement devices as Electronics Seminar Topics:

Ultrasonic Distance measurement seminar must contain following things.

1. Ultrasonic Sound Introduction.
2. Ultrasonic Devices.
3. Construction and working of Ultrasonic Device.
4. Principle of working.
5. Advantages.
6. Limitations.
7. Applications.

Related Topics and Articles:

1. Ultrasonic Devices
2. Ultrasonic Flowmeters
3. Ultrasonic Level Sensor