Raspberry Pi Files

BasicGPIO

Hello Jared! I have included three files that you can copy to your Raspberry Pi.

some terminal tips are also included at the end.

This is a collection of Python files that test the RPi.GPIO module.

turnon.py

this file is simple, it just turns on GPIO4 for 10 seconds. Use this file to test if GPIO4 is actually working. The red wire of the speaker should be connected to GPIO4, The black wire of the speaker should be connected to GND.

when you run the program, the speaker should turn on. When the program ends, the speaker should be off. If the Raspberry Pi does not work like this, the circuit is connected incorrectly.

beepbeep.py

This file simply turns GPIO4 on and off for 10 times.

volume.py

this file makes a PWM (pulse width modulator: turns voltage on and off really fast to simulate a lower voltage) to control the volume of the speaker. You can control the volume of the speaker by editing the code or inserting it in the command line

duty_cycle = 10

change this ^ to change the default volume of the speaker

python filename.py 40

enter this in the terminal ^ to input a volume percentage. Changing this does the same thing as changing the duty cycle, but its a lot faster

Gui - PyQt5

This is a collection of Python files that use PyQt5 to create small GUI applications to manage the

qt_template.py

this is a template file that makes a class called MainWindow() to easily sort the code of the main window.

class MainWindow(QtWidgets.QtWidgets):
    def __init__(self):
        #MainWindow Constructor
        super().__init__()
        #Custom Code Start

        #Custom Code End
        self.show

You declare all other widgets where "Custom Code Start" is.

test_button.py

This file merges functionality with the RPi.GPIO library and PyQt5. This file demonstrates how to pass in functions as callbacks, and how to run code on the PyQt app's exit.

class MainWindow(QWidgets.QWidget):
    def __init__(self):
        ...
        self.button = QtWidgets.QPushButton("x", self, 
            checkable=True, 
            checked=False
        )
        self.button.clicked.connect(self.button_toggled) 
        #the button will call button_toggled(self, bool) when clicked
        ...
    def button_toggled(self, checked):
        print(f"state: {checked}")
        #code that runs whenever the button is clicked

as demonstrated by the code above, you can define callback functions that would be called once the button is clicked. Alternatively, if the function that you want to execute is small (meaning that it only consists of one line), then you may use lambda functions.

self.button.clicked.connect(lambda self, checked: print(f"state: {checked}")

when you need to have code that must run when the app closes, you must store app.exec()'s result in a variable, and then you may write the code that must be run on exit. Once done, pass the result to sys.exit().

if __name__ == "__main__": #code that only runs when the file is explicity called in the terminal
    res = app.exec()
    print("closed") #runs when the app/GUI is exited
    GPIO.cleanup()
    sys.exit(res)

terminal tips

ls command: every terminal has its location. If you want to see every file in your current location (directory), type:

ls

cd command: This tells you the names of all the files and folders that is in your current location. CD lets you change locations to other folders/directories

cd Documents

cd ../

this ^ changes you to the parent folder

mv command: to change the name of a file, use the mv command

mv badfilename.py volume.py

this ^ renames badfilename.py to volume.py. it stands for move