We cut the designed trapezoidal coils with dimensions, a large side 30cm, a small side 15cm and a height of 15cm, according to the Figure 4, on the wood by CNC machine. The coils are designed to be movable so that we can measure the field at different distances. To select the proper wire for this coil model, it is necessary to calculate the maximum tolerable current. This current is calculated by equation 2:¹⁷

$I=\frac{\pi .d^2}{4}.\sqrt{\frac{\frac{\Delta T}{t}.c.\rho m}{\rho r}}$    (2)

Figure 4 The dimensions of the proposed trapezoidal coil.

Where in,  is the current that passes through each coil,  is the diameter of the wire, shows the increase in temperature over time, c is the specific heat capacity of the wire,  is the capacity of the wire and is the resistance of the wire. We chose the right wire according to the process we had. Wire used for coiling coils, sieve coated copper wire with 1.25 mm thick, 1kg approximate total weight of wire and in 40 rounds of wrapped wire, 36m of wire is used. This wire model was chosen because of its light weight and suitable thickness for hand coiling and tolerating voltage and current. We coiled the coils and connected them in series to the voltage source (Figure 5).

Figure 5 The real image from trapezpidal coil.

The real time measurement of the magnetic flux density

To test the device, need a sensor that measures the field intensity produced by the device. In this project, we ‎use the principle of analogue to digital signal conversion in Arduino. The Arduino is a single-board ‎microcontroller designed to make it easier to create applications that interact with objects or ‎environments. The Arduino board is built on the microcontroller at mega 328p. The Arduino has ‎six analogue-to-digital channels. The UNO ADC has 10 bits of resolution that will have values of 0 to ‎‎1023. This means that it converts the voltage between 0 to 5 volts into 0 to 1023units, So each ‎unit is equal to 4.9mV. Arduino comes with an integrated IDE software development ‎environment that runs on ordinary computers that allow Arduino to use C or C++ programming.¹⁸ In this project, the code used to program the microcontroller is shown (Figure 6).

Figure 6 The Arduino board, UNO ADC type.

#include <LiquidCrystal.h>

//initialize the library with the numbers of the interface pins

LiquidCrystal lcd(8, 9, 10, 11, 12, 13);/// REGISTER SELECT PIN , ENABLE PIN , D4 PIN , D5 PIN , D6 PIN , D7 PIN

char ADCSHOW[5] ; //initializing a character of size 5 for showing the ADC result

void setup()

{

// set up the LCD’s number of columns and rows:

lcd.being(16,2);

}

void loop()

{

lcd.print(“FluxDensity”);//showing name

lcd.setCursor(0, 1);//move to second line

lcd.print(“(in Gauss):”);//showing units

String ADCVALUE =

String((analogRead(A0)-515)/3.76);

 /* Now since the default reference if 5V and resolution is 10bit so for every 5/1024 = 5Mv , we get one increment is count , The sensor provides increment voltage of 1.3V for every 1Gauss increment if field.

So we need to divide ADC value by 3.76 for getting the gauss value , now the 0 gauss output of sensor is 2.5V so we need to subtract that first. To hold a read at 0Gauss field. */

// Convert the reading to a char array ADCVALUE. ToCharArray(ADCSHOW, 5);

lcd.print(ADCSHOW) ; //showing the field

strength value

lcd.print(“G “);

lcd.setCursor(0, 0); // set the cursor to

column 0, line 0

}

We used a Hall effect sensor to measure the magnetic field flux. The name of the sensor we used is UGN3503U. The sensor is a transducer Hall effect sensor, which shows voltage in response to changes in the output magnetic field. By applying a large magnetic field, the voltage is in the range of a few microvolts. If it is not adjacent to the magnetic field, the sensor has a constant output voltage of about 2.5volts (about half the supply voltage) at the sensor output. The operating voltage range of the sensor is between 4.5 and 6V and the operating current of the sensor is between 9 and 13 mA.¹⁹ The Figure 7 shows a schematic of a UNG3503U sensor with tripod.^20,21 When the magnetic field flux is measured by the sensor, its value is displayed on the LCD. LCDs include a variety of characters and graphics. Here's the type of character we used. Character displays are also divided into parallel and serial categories in terms of information exchange. One type of serial is less use of microcontroller pins. In terms of size, these have different variations, including 16×2, 32×2, 40×2, 16×4 and so on, which means these numbers, the number of characters displayed in a row and Its rows.²² For example, type 16×2 has 2 rows and represents 16 characters per row. In this project, we have used type 16×2 which is very useful (Figure 8). Schematic of the overall circuit of the magnetic field flux measuring sensor, designed by the elements mentioned above and shows in the Figure 11 & Figure 9. This sensor is located between the coils, and when applied to the magnetic field, it displays the magnitude of the magnetic field at different distances between the coils in Gauss. Finally, we connected the dc source (5Volts) to the coils and the magnetic field measuring circuit and adjusted the distance between the coils to 4cm. The field generated by the new trapezoidal coil was measured with a sensor. We plot the results in Figure 10. From the measurement of the magnetic field intensity with the voltage change, it was concluded that the field changes in terms of voltage changes are almost linear (Figure 11).

Figure 7 A) UGN3503U Hall effect sensor.²⁰ B) the schematic of Hall effect sensor.²¹

Figure 8 LCD used in this project is 16×2 type.

Figure 9 Electronic circuit of magnetic field flux measuring sensor.

Figure 10 The experimental result of the magnetic field flux measured by the sensor in terms of voltage applied to the coils.

Figure 11 The diagram of the overall circuit of the magnetic field flux measuring sensor./p>

We know that smart drug delivery has a remarkable role in the treatment of cancers because with the use of nano-drug knowledge, the drug works only in the affected area and does not cause complications in healthy areas of the body. The purpose of this project was to design a new magnetic coil that is different from the conventional circular coils used in medical applications. The trapezoidal coil that designed is proposed in biomedical domain because of its geometrical shape. This specific design permits us to use it in several investigations. This geometry has many advantages compared to the cylinder coil. For example, in MRI diagnostic the patient has a more open space and is useful for technician or physician freedom and the patient will feel more comfortable and these properties and the geometrical shape of the trapezoidal coil have not eliminated the homogeneous property of the field.

None.

None.

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20. https://www.ebay.com/p/Ugn3503u-UGN-3503u-Transistor/23016584269
21. https://www.datasheetq.com/image/Allegro/254755.gif
22. https://electronicsforu.com/resources/learn-electronics/16x2-lcd-pinout-diagram