#
# hello.light.45.py
#
# receive and display light level
#
# Neil Gershenfeld
# CBA MIT 10/24/07
#
# (c) Massachusetts Institute of Technology 2007
# Permission granted for experimental and personal use;
# license for commercial sale available from MIT
#
# Modified by Inna Koyrakh
#

from Tkinter import *
import serial
import random



#
# Filtering variables
#
WINDOW = 600
eps = 0.1
#saveflag = 0
#
# Usable sensor values
#
filter = 0.0
minVal = 2000.0
maxVal = 1.0
R = 100
#
# Canvas positioning and dimensions
#
cMin_x = 0
cMin_y = 0
cMax_x = 450
cMax_y = 300
#
# Canvas center
#
center_x = 0.5*(cMin_x+cMax_x)
center_y = 0.5*(cMin_y+cMax_y)



#
# open serial port
#
ser = serial.Serial('COM13',9600)
ser.setDTR()



def idle(parent,canvas):
   global minVal, maxVal, cMax_x, cMax_y, filter, eps #saveflag
   #
   # idle routine
   #
   byte2 = 0
   byte3 = 0
   byte4 = 0
   ser.flush()
   while 1:
      #
      # find framing 
      #
      byte1 = byte2
      byte2 = byte3
      byte3 = byte4
      byte4 = ord(ser.read())
      if ((byte1 == 1) & (byte2 == 2) & (byte3 == 3) & (byte4 == 4)):
         break
   low = ord(ser.read())
   high = ord(ser.read())
   value = 256*high + low
   filter = (1-eps)*filter + eps*value
   #
   # learn current working range of sensor
   #
   if filter <= minVal:
      minVal = filter
   if filter >= maxVal:
      maxVal = filter
   #
   # GUI parameters
   #     
##   maxDir = max(center_x, center_y)
##   R = random.uniform(0, maxDir) # function of intensity
   R = 0.5*(filter/maxVal)*cMax_x
   canvas.coords('circle', center_x-R, center_y-R, center_x+R, center_y+R)
   canvas.update()
   parent.after_idle(idle,parent,canvas)



#
# set up GUI
#
master = Tk()
master.title('hello.light.45.py (q to exit)')
master.bind('q','exit')
#
# Initialize canvas
#
canvas = Canvas(master, width=450, height=300, background='white')
canvas.create_oval(center_x-10, center_y-10, center_x+10, center_y+10, tags='circle', fill='#0000b0')
canvas.pack()
#
# start idle loop
#
master.after(1000,idle,master,canvas) # ms allowed for startup
master.mainloop()