# arc_rpm.py

# arc_rpm.py

import tkinter as tk
import math
root = tk.Tk()
width,height=410,310 # set the variables
d=str(width)+"x"+str(height+40)
root.geometry(d)
canvas = tk.Canvas(root, width=width-10, height=height-50,bg='#FFFFFF')
canvas.grid(row=0,column=0)
arc_w=50 # width of the arc
x1,y1,x2,y2=35,35,355,355 # dimensions for the arc
x,y,r=195,195,150

canvas.create_arc(x1, y1,x2,y2, start=0, extent=20,outline='red',
         width=arc_w,style=tk.ARC)
canvas.create_arc(x1, y1,x2,y2, start=20, extent=30,outline='orange',
        width=arc_w,style=tk.ARC)
canvas.create_arc(x1, y1,x2,y2, start=50, extent=40,outline='yellow',
        width=arc_w,style=tk.ARC)
canvas.create_arc(x1, y1,x2,y2, start=90, extent=90,outline='green',
        width=arc_w,style=tk.ARC)

# small circle at center
canvas.create_oval(x-10,y-10,x+10,y+10,fill='dark gray',width=0)
in_radian=math.radians(180) # getting radian value

def draw_line(in_radian):
    return canvas.create_line(x,y,(x+r*math.cos(in_radian)),
            (y-r*math.sin(in_radian)),width=6)

def my_upd(value):
    global line
    in_radian = math.pi - math.radians(my_scale.get()) # scale value in radian
    canvas.delete(line) # delete the pointer
    line = draw_line(in_radian)
line = draw_line(in_radian)

my_scale = tk.Scale(root, from_=0, to=180, orient='horizontal',
 length=395,command= my_upd)
my_scale.grid(row=2,column=0)
root.mainloop()