Prerequisite : Introduction to pyqt-5
In this article, we will see how we can create a quarter(1/4) mile calculator using PyQt5. Quarter mile calculator is used to determine the terminal speed (trap speed) and quarter-mile elapsed time (ET) of a vehicle based on its weight and power.
Below image shows how the 1/4 mile calculator looks like :
1/4 mile calculator
The quarter-mile calculator employs three distinct empirical equations to determine the quarter-mile elapsed time (ET). These are as follows:
1. Roger Huntington’s Equation:
Time = 6.290 × (Weight / Power)^(1/3)
2. Geoffrey Fox’s Equations:
Time = 6.269 × (Weight / Power)^(1/3)
3. Patrick Hale’s Equations:
Time = 5.825 × (Weight / Power)^(1/3)
Note: Here weight is in Pound (lb) and power is in horsepower (hp) units.
GUI Implementation Steps :
1. Create a heading label that display the calculator name
2. Create label and combo box pair for selecting equation, label to show what user has to select and combo box to select
3. Similarly create a pair of label and line edit to get the weight and power of car
4. Create a push button to calculate the time
5. Create a label to show the calculated time
Back-End Implementation :
1. Make the combo box non editable
2. Make the line edit to accept only the number as input
3. Add action to the push button
4. Inside the push button action get the text of the line edits
5. Check if the line edit text is empty or zero then return so that function will not execute further
6. Convert the text value into integer
7. Get the selected option from the combo box and set constant value according to it
8. Calculate the time and show this value through the label
Below is the implementation :
Python3
# importing required libraries from PyQt5.QtWidgets import *from PyQt5 import QtCore, QtGui from PyQt5.QtGui import *from PyQt5.QtCore import * import sys class Window(QMainWindow): def __init__(self): super().__init__() # setting title self.setWindowTitle("Python ") # width of window self.w_width = 400 # height of window self.w_height = 450 # setting geometry self.setGeometry(100, 100, self.w_width, self.w_height) # calling method self.UiComponents() # showing all the widgets self.show() # method for components def UiComponents(self): # creating head label head = QLabel("1/4 Mile Calculator", self) # setting geometry to the head head.setGeometry(0, 10, 400, 60) # setting font font = QFont('Times', 15) font.setBold(True) font.setItalic(True) font.setUnderline(True) # setting font to the head head.setFont(font) # setting alignment of the head head.setAlignment(Qt.AlignCenter) # setting color effect to the head color = QGraphicsColorizeEffect(self) color.setColor(Qt.darkCyan) head.setGraphicsEffect(color) # creating a label e_label = QLabel("Equation", self) # setting properties label e_label.setAlignment(Qt.AlignCenter) e_label.setGeometry(20, 100, 170, 40) e_label.setStyleSheet("QLabel" "{" "border : 2px solid black;" "background : rgba(70, 70, 70, 35);" "}") e_label.setFont(QFont('Times', 9)) # creating a combo box to selected equation self.equation = QComboBox(self) # adding items to the combo box items = ["Huntington", "Fox", "Hale"] self.equation.addItems(items) # setting properties to the combo box self.equation.setFont(QFont('Times', 9)) self.equation.setGeometry(200, 100, 180, 40) self.equation.setEditable(False) # creating a label w_label = QLabel("Car Weight (lb)", self) # setting properties to the label w_label.setAlignment(Qt.AlignCenter) w_label.setGeometry(20, 150, 170, 40) w_label.setStyleSheet("QLabel" "{" "border : 2px solid black;" "background : rgba(70, 70, 70, 35);" "}") w_label.setFont(QFont('Times', 9)) # creating a QLineEdit object self.weight = QLineEdit(self) # accepting only number as input onlyInt = QIntValidator() self.weight.setValidator(onlyInt) # setting properties to the line edit self.weight.setGeometry(200, 150, 180, 40) self.weight.setAlignment(Qt.AlignCenter) self.weight.setFont(QFont('Times', 9)) # creating a label p_label = QLabel("Engine Power (hp) ", self) # setting properties to the years label p_label.setAlignment(Qt.AlignCenter) p_label.setGeometry(20, 200, 170, 40) p_label.setStyleSheet("QLabel" "{" "border : 2px solid black;" "background : rgba(70, 70, 70, 35);" "}") p_label.setFont(QFont('Times', 9)) # creating a QLineEdit object self.power = QLineEdit(self) # accepting only number as input onlyInt = QIntValidator() self.power.setValidator(onlyInt) # setting properties to the line edit self.power.setGeometry(200, 200, 180, 40) self.power.setAlignment(Qt.AlignCenter) self.power.setFont(QFont('Times', 9)) # creating a push button calculate = QPushButton("Calculate Time", self) # setting geometry to the push button calculate.setGeometry(125, 270, 150, 40) # adding action to the calculate button calculate.clicked.connect(self.calculate_action) # creating a label to show percentile self.result = QLabel(self) # setting properties to result label self.result.setAlignment(Qt.AlignCenter) self.result.setGeometry(30, 340, 340, 80) self.result.setWordWrap(True) self.result.setStyleSheet("QLabel" "{" "border : 3px solid black;" "background : white;" "}") self.result.setFont(QFont('Arial', 11)) # method for calculating the # quarter-mile elapsed time (ET) def calculate_action(self): # getting weight of car weight = self.weight.text() # getting power of engine power = self.power.text() # if no input is given close the function if len(weight) == 0 or len(power) == 0: return # converting weight into integer weight = int(weight) # converting power into integer power = int(power) # if user enter total value as 0 # return the function if power == 0 or weight == 0: return # getting the selected equation index equation = self.equation.currentIndex() # setting constant value according to the equation # Roger Huntington's constant if equation == 0: constant = 6.290 # Geoffrey Fox's constant elif equation == 1: constant = 6.269 # Patrick Hale's constant else: constant = 5.825 # calculating the time result = constant * ((weight/power)**(1/3)) # formatting the time result = "{:.2f}".format(result) # setting text to the result label self.result.setText("1/4 Mile Elapsed Time : " + str(result) + " seconds") # create pyqt5 app App = QApplication(sys.argv) # create the instance of our Window window = Window() # start the app sys.exit(App.exec()) |
Output :
