RPM_calc.py

from tkinter import *
from math import pi
class RMP_mesure:
    def __init__(self):
        self.quit = False
        self.root = Tk()
        self.root.protocol("WM_DELETE_WINDOW", self.quitter)
        self.root.title("RPM Converter")
        self.root.geometry("250x100+100+100")
        self.root.configure(bg="white")
        self.output = None

    def calc(self, event, rd, rp):
        try:
            rd = float(rd.get())
        except:
            self.output.delete(0, END)
            self.output.insert(0, "Please insert Radius as a floating point number")
            self.output.configure(fg="red")
        try:
            rp = int(rp.get())
        except:
            self.output.delete(0, END)
            self.output.insert(0, "Please insert RPM as a floating point number")
            self.output.configure(fg="red")
        rps = rp/60
        c = 2*pi*rd
        dis = c*rps
        mps = dis/100
        self.output.delete(0, END)
        self.output.insert(0, "%s m/s"%str(mps)[0:str(mps).index(".")+3])
        self.output.configure(fg="black")

    def run(self):
        f1 = Frame(self.root, bg="white")
        f1.pack(side=TOP, fill=X)

        f2 = Frame(self.root, bg="white")
        f2.pack(side=TOP, fill=X)

        f3 = Frame(self.root, bg="white")
        f3.pack(side=TOP, fill=X)

        f4 = Frame(self.root, bg="white")
        f4.pack(side=TOP, fill=X)

        Label(f1, text="Radius(cm)", width=10, justify=RIGHT, anchor="e", bg="white").pack(side=LEFT)
        rd = Entry(f1)
        rd.pack(side=LEFT, fill=X)

        Label(f2, text="RPM", width=10, justify=RIGHT, anchor="e", bg="white").pack(side=LEFT)
        rp = Entry(f2)
        rp.pack(side=LEFT, fill=X)

        self.output = Entry(f3, bg="white", fg="black")
        self.output.pack(fill=X, expand=1)


        Button(f4, text="Calculate", bg="white", command=lambda e=Event(), rd=rd, rp=rp: self.calc(e, rd, rp)).pack(fill=X, expand=1)

        while not self.quit:
            self.root.update()
            self.root.update_idletasks()

    def quitter(self):
        self.quit = True


if __name__ == "__main__":
    app = RMP_mesure()
    try:
        app.run()
    except KeyboardInterrupt:
        app.quitter()
    except:
        raise