Ultrasonic Radar And Its Applications

The Ultrasonic Radar System

Discuss about the Ultrasonic Radar and its Applications.

According to (Tamhankar, Mittal & Singh, 2009), “A radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction or speed of both moving and fixed objects such as aircrafts, ships, motor vehicles, weather information and terrain. When ultrasonic waves are used, it is called an ultrasonic radar. “Ultrasonic waves are sound waves that are greater than 20 kHz. An ultrasonic radar composes of various components. However, the main component of the radar is the ultrasonic sensor. It works on a principle similar to the radar, evaluating a target`s distance by interpreting echoes that are produced from radio or sound waves respectively (Tamhankar, Mittal & Singh, 2009). The distance of the intruder object is calculated by the sensors after estimating the difference in time of the transmitted wave to come back to the receiver as an echo. However, quite a number of data is required in order to provide useful information on the moving object`s` location. In order to achieve this, various technologies are used in the ultrasonic radar system. These technologies compose of a microcontroller, ultrasonic module and a microwave distance detector. The direction detector measures the distance between the transmitter and receiver by pulse wave via the path of transmission thereafter the intruder object bounces back the pulse wave back to the receiver after sending a burst pulse signal through the transmission path. The time interval between the reflected echoes from the object to the ultrasonic module is equal to the distance of the object. If there is no obstacle along the path of the transmitted wave, there is no interference and similar waves are transmitted back to the receiver, hence, there is no object detection. The system is therefore very efficient as it detects presence of any object of distraction within the prohibited area.

According to (Gourav et al., 2017), ultrasonic radar works best in air since it can measure longer distances as compared to when the radar system is on the ground where it measures a limited distance offering short range communication (Gourav et al., 2017.). (Gourav et al., 2017) added that in air they are excellent sensors which use wave propagation phenomenon in air to measure the variables that could either be physical or chemical. Through this principle the air ultrasonic detectors evaluate amplitude and propagation time. These systems also involve the use of transducers to generate sound waves in the ultrasonic waves. Transducers are elements that convert one form of energy to another since energy can neither be created nor destroyed, but it can be transformed from one state to another. It goes then that the transducer converts the sound energy into electrical energy and also converts the sound energy to electrical energy. The transducers are vital in the ultrasonic transmitter which requires transmission of sound into electrical energy and receivers which require the transmission of the electrical energy to sound energy. This is only possible because the transducers enable the energy conversion in these two devices. Conversion of electrical energy into sound energy by the transducer device initiates sound waves that are of ultrasonic range of above 20 kHz. Old radar systems used sound alarms or light emitting diodes (LED) to alert authorities. However, modern systems use liquid crystal display (LCD) units to show the detailed information of the target object. A computer screen is used to show distance and angle of the object in the system. According to (Shakir, Mohammed & Abdulkareem, 2016), with these modern systems, various inventions like the Google auto drive vehicles have been invented, militaries could spot enemies in the ocean, miles away and even fire at them in time and people`s home security has been made better.

Objective of the Ultrasonic Security System

The ultrasonic radar security system is to be used for detection, distance and speed measurement after an object is fixed in the range of the ultrasonic sensor. Also another objective is to calculate the time interval between the transmitted pulse wave and the received echo in order to be able to obtain the distance between the object and the ultrasonic sensor, and displaying results on the liquid crystal display (LCD) unit. Another objective is to find out where else the system could be used in order to advance the technology on the identified sector.

Figurative diagram showing the object detection mechanism as the waves are transmitted from the transmitter and back to the receiver which receives waves containing an interrupt that identifies the presence of the intruder object.  Available from, https://www.jetir.org/papers/JETIR1604028.pdf

The ultrasonic radar security system is made up of various structures in the system. Each of the structures plays a vital role in ensuring that the ultrasonic system works efficiently. Some of the system`s parts are discussed in brief in the following section.

It is a very important structure that contains the microcontroller and open collector buffer which are the most important parts of the system. The microcontroller is a vital part of the system that facilitates the operation of all other parts of the ultrasonic radar system. Therefore, a good microcontroller should be used in the experiment.

About 40 kHz is required for the radar system since an ultrasonic wave is requires and the wave is greater than 20 kHz. The 40 kHz is thus produced in the microcontroller. The 8051 series Microcontroller is used in this experiment. This is because it has timers that correctly generate the 40 kHz which would otherwise have been difficult to produce with other microcontrollers. The output of the microcontroller is amplified using an open collector buffer circuit since it cannot be used in the volts it is produced with since they are insufficient.

The open collector buffer is an inverter with the open collector at the input. A 10000 resistor from the output is connected to 15 Volts. An inverter is placed before the open collector buffer in order to ensure that the signal polarity is maintained as that of the input. An integrated circuit (IC 7406) inverter is used to help the open collector buffer achieve its purpose. In addition, an IC 7404 is also used to invert the output of the microcontroller. Older open collector buffers are not used. For instance the Op Amperes is not used because a square shaped pulse wave is required as the output bandwidth at the 40 kHz in order to cover more distance. Instead it produces a triangular shaped output which is an unwanted wave shape. The square shape is preferred as it covers more distance of the area being secured than the triangular shaped output wave.

Advantages of Ultrasonic Radar System

The sound waves received by the ultrasonic receiver are converted into pulses of electrical nature that are mostly smooth continuous waves (sinusoids). A signal of about 40 mV to 50mV is received. It is amplified to about 100mV in order to enable the processing as it gains a few range of volts. Op Amperes can be used as receivers because the shape of the pulses that are received is not a vital issue as for the transmitter. Only the amplitude`s measurement in order to produce an amplitude is vital in the receiver.

According to (Gourav et al., 2017), an interrupt is required in order to make the microcontroller aware about the detection of an object, hence an interrupt generator circuit is used. It comprises of a Schmitt trigger which gives a high output whenever its input is above a threshold value or else it remains at low value. The output of the Schmitt trigger is inverted with respect to the input signal, hence, in order to reinstate the phase, the output of the Schmitt trigger is inverted and thereafter given to the microcontroller, The microcontroller then decides the distance of the object from the sensor by calculating the delay between the time of sending pulses and the interrupt produced.

The sequences of the motor are controlled by the microcontroller. It is important for the system to have a current. Therefore, the current is generated by a motor driver integrated circuit. The stepper motor is put at a steep angle of 1.8 degrees. In the experiment, it is put at a 14.4 degrees steep from where the assessment is done from at this point, after getting an echo from the interrupt, resulting from a threshold that is lesser than the received voltage.

Various software application are required in the system to convey the data from the hardware to a display system. For this reason, the ultrasonic radar systems use soft wares that are easy to use for normal operators in order to eliminate the use of soft wares that require training. Also these soft wares are required to be affordable in order to lower the cost of the ultrasonic radar. Some of the soft wares that are used are like the Arduino UNO model and Keil μ Vision Model. In the experiment, Keil μ Vision model is used for the transmission of data into software from the hardware.

Keil is a hardware and software company that designs and manufactures computer open source hardware and open source soft wares and microcontroller based kits for building digital devices and interactive objects that can sense and control physical devices (Arm Limited, 2018). The Keil projects are based on microcontroller board designs and they combine project management, run time environment, build facilities source code, editing and program debugging in a single powerful environment. It supports multiple screens and allows creation of individual window layouts anywhere on the visual surface. The board provides sets of digital and analog Input/output pins that can interface to various terminal shields and other circuits. The boards have serial communication interfaces like Universal Serial Bus for loading programs from personal computers. The model also comes with debuggers that allow for testing, verification and optimization of the application code in a single environment. The debugger also has simple and complex breakpoints, watch windows and execution controls, and provides full visibility to device peripherals. The software works well with the MC programming language C or C++. In the experiment programming language C is used for the ultrasonic system.

Applications of Ultrasonic Radar System

It displays the output, normally a line scan moving from 0 to 180 degrees as the stepper moves and whenever an object is detected, the liquid crystal display unit develops the object at that point in terms of latitudes and longitudes. The display could also be a light emitting diode that lights whenever there is an intruder object in the area under protection. After its lighting, the display unit shows the distance and angle of the intruder object and proper action can be taken.

Before the display system was established the ultrasonic sensors utilized alarms for alerting authorities the presence of intruders. The sound energy was therefore sent off as an alarm that would go off. The recent use of liquid crystal display units is however more efficient than the sound alarms.

Schematic diagram showing the presence of three intruder objects within the radius of the ultrasonic sensor. The objects are being displayed as light emitting objects in the display system. Available from, https://www.ee.iitb.ac.in/uma/~wel/wel45/public_html/edl09a/dd07.pdf

The following represents the schematic diagram that represents how the board server of the ultrasonic radar system is like and the connection in the system. It shows that the motor goes through 180 degrees scanning for the intruder object in the area under protection and whenever it detects an intruder object the light emitting diode lights and the distance and angle of the object is displayed on the screen indicating a successful experiment.

The ultrasonic transducers use the physical traits and the corresponding effects of ultrasonic waves of various frequencies. Piezoelectric or electromagnetic signals are the versions used by the transducer to transmit or receive ultrasonic wave signals of particular strength. The affordability (low cost) and ease of use of the piezoelectric signals make them the most frequently used signals in transmission and reception of ultrasonic waves from the transducers. According to (Singh, Agnihotri & Patel, n.d.), the ultrasound velocity is governed by the medium and its temperature and hence, the velocity in air is calculated using the formula: V = 340 + 0.6 (T - 15) m/s, where T is the temperature in degrees Celsius. Obtaining the transmitting and receiving signal of the ultrasonic signal by measuring the display on the provided liquid crystal display unit is as a result of calculation of the travel time of the transmitted and received waves in order to obtain the distance

The formula to calculate the distance is Distance = (Travel time × 10⁶ × 34300), or the time delay between the corresponding edges of the two transmitted and received pulses is measured by the microcontroller as this gives the time of flight. Substituting the time delay and the velocity of ultrasound in the air (330m/s) in the following formula will give the distance between the target and transmitter too: Distance = (Velocity × Elapsed Time).

Conclusion

The following represents a flow chart diagram showing how the ultrasonic radar system works from the microcontroller until it detects an object in its radius and sends a signal.

• Using the input-output trigger for at least 10 us high level signals.
• The module automatically sends eight 40 kHz and detects whether there is a pulse signal back.
• If the signal is back through the high level, time of high output input-output duration, is the time from sending the ultrasonic wave to returning.

Ways of Connecting the Wires in the Ultrasonic System.

• 5 Volts supply.
• Trigger pulse input.
• Echo pulse output.
• 0 Volts ground.

Hardware Specifications

• 8051 series Microcontroller
• Diodes
• Liquid crystal display Unit
• Ultrasonic module
• Servo Motor
• Transformer
• Light emitting Diodes.
• Transistor
• Voltage Regulator
• Crystal

Software Specifications

• Keil µVision IDE
• MC Programming Language: Embedded C

The ultrasonic sensor was connected to pins 10 and 11 of the Keil Board. These pins represented the transmitter pin and receiver echo pin. The serve motor was pinned to pin number 12 where it could rotate at angles of 180 degrees. The circuit`s schematic diagram was as follows:

The sketch was then uploaded in Keil and a built in library was used for data transfer through the serial port with processing software. Thereafter, a code was made and uploaded on the board in order to enable the interactions between the hardware and software in the system.

Conclusion

The ultrasonic radar system is a very useful system in the provision of security in a system. As seen it accurately measures the distance and angle of the intruder object in the area under security and displays the intruder in the system`s display or may turn on an alarm to alert the authorities. The speed of the object can also be calculated by these sensors making them very efficient in many other operations like the navy operations in detecting sea intruders or even the air force, detecting intruders from the sky. The method involves basically the microcontroller that is the main unit of control for the system. It includes a transmitter and receiver that send and receive the waves that are used to calculate the distance of the object. There is also a motor that rotates these two in order to increase the distance measured. The system is thereafter connected to soft wares that can be able to interpret the results accurately and provide the accurate information on the distance and angle of the object. The project was therefore a success as the ultrasonic radar was created and was functional, being able to detect the distance and angle of intruding objects correctly. Moreover, a user friendly software was obtained in order to interpret the results from the ultrasonic system. According to (Kadam et al., 2017) the ultrasonic radar systems are promising even in other sectors like the automobile vehicles where in the near future they will be used to create auto driving cars. The dawn of this phenomenon is here since some cars can park themselves.

The ultrasonic system developed was efficient in detecting the object within the radius of the ultrasonic sensor. This limitation of the radius as discussed was due to the fact that the ultrasonic sensor was not operating from air where it has a larger communication radius. Hence, in order to improve the sensor, it could be used while in air. In addition to that, a camera can be added as part of the display in order to show the image of the intruder object. This would be efficient in home burglar alarm systems as the home owner can see what weapons the intruder has in addition to knowing their exact location in the house. The camera in the ultrasonic systems could be utilized by automobile companies too, while making auto driving vehicles as the cameras will enable the car detect the object within its sensor`s` radius and avoid causing accidents while auto driving. The ultrasonic sensors are therefore vital for the future of science and technology as they have very many applications. The experiment was a success since the ultrasonic radar sensor was able to detect the objects within its distance and also calculate the distance of the object from the sensor itself.

References.

Tamhankar, Mittal, & Singh. (2009). Ultrasonic Radar and its Applications. Retrieved from https://www.researchgate.net/publication/308415857_A_Short_Range_Radar_System?enrichId=rgreq-aa5208671b1442808d5ba05c6eac5584-XXX&enrichSource=Y292ZXJQYWdl  

Gourav, D., Dhanashri, N., Krushna, H., Shaikh, D. A. (2017). Ultrasonic Radar for Object Detection, Distance and Speed Measurement. International Journal of research in Advent Technology (IJRAT). ISSN: 2321-9637. Retrieved from https://www.ijrat.org/downloads/MOMENTUM17/MOMENTUM17-69.pdf 

Singh, C., Agnihatri, A., & Patel, P. (n.d.). Development of Radar Using Ultrasonic Sensor. International Journal of Advance Research in Science and Engineering.

Arm Limited. (2018). μ Vision IDE. Retrieved from https://www2.keil.com/mdk5/uvision/ 

Kadam, D. B., Yuvrj, B., Krishnat, V., & Swagat, S. (2017). Arduino Based Moving Radar System. International Journal of Innovative Studies in Science and Engineering Technology. (Vol.3). ISSN: 2455-4863. Retrieved from https://ijisset.org/wp-content/uploads/2017/04/IJISSET-030405.pdf 

Shakir, M., Mohammed, A., & Abdulkareem, M. (2016). A Short Range Radar System “Radarfinder”: Robotics and Sensing. University of Turkish Aeronautical Association. Retrieved from https://www.researchgate.net/publication/308415857_A_Short_Range_Radar_System?en richId=rgreq-aa5208671b1442808d5ba05c6eac55XXX&enrichSource=Y292ZXJQYWdl 

https://www.ee.iitb.ac.in/uma/~wel/wel45/public_html/edl09a/dd07.pdf 

https://www.ee.iitb.ac.in/uma/~wel/wel45/public_html/edl09a/dd07.pdf 

https://www.jetir.org/papers/JETIR1604028.pdf

https://www.ijrat.org/downloads/MOMENTUM17/MOMENTUM17-69.pdf 

https://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1426192&queryTexr=ultrasonic%20radarnewsearch=true