# # hello.temp.44.py # # receive and display temperature # hello.temp.44.py serial_port # # Mani Sai Suryateja Jammalamadaka # Modified code of Neil Gershenfeld # MIT 12/03/2018 # # (c) Massachusetts Institute of Technology 2012 # Permission granted for experimental and personal use; # license for commercial sale available from MIT # from Tkinter import * from numpy import log import serial WINDOW = 600 # window size eps = 0.5 # filter time constant filter1 = 0.0 # filtered value filter2 = 0.0 # filtered value i=1 def idle(parent,canvas): global filter1, filter2, i, eps #declaring i, filter1 and filter2 as global variable # # 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 if (value > 511): value -= 1024 V = 2.5 - value*5.0/(20.0*512.0) R = 10000.0/(5.0/V-1.0) # NHQ103B375R5 # R25 10000 (O) # B (25/85) 3750 (K) # R(T(C)) = R(25)*exp(B*(1/(T(C)+273.15)-(1/(25+273.15)))) B = 3750.0 R25 = 10000.0 T = 1.0/(log(R/R25)/B+(1/(25.0+273.15))) - 273.15 if i % 2 == 0: filter1 = (1-eps)*filter1 + eps*T #if even, filter1 filters the temperature of themistor1 controlled by mosfet1, otherwise filter2 filters the temperature of thermistor2 controlled by mosfet2 else: filter2 = (1-eps)*filter2 + eps*T #if even, filter1 filters the temperature of thermistor1 controlled by mosfet1, otherwise filter2 filters the temperature of thermistor2 controlled by mosfet2 filter=filter2-filter1 #difference of temperatures of thermistor2 and thermistor1 i += 1 x = int(.2*WINDOW + (.9-.2)*WINDOW*(filter)/10.0) #adjusted it to fit the window canvas.itemconfigure("text",text="%.2f"%filter) canvas.coords('rect1',.2*WINDOW,.05*WINDOW,x,.2*WINDOW) canvas.coords('rect2',x,.05*WINDOW,.9*WINDOW,.2*WINDOW) canvas.update() parent.after_idle(idle,parent,canvas) # # check command line arguments # if (len(sys.argv) != 2): print "command line: hello.temp.44.py serial_port" sys.exit() port = sys.argv[1] # # open serial port # ser = serial.Serial(port,9600) ser.setDTR() # # start plotting # root = Tk() root.title('hello.temp.44.py (q to exit)') root.bind('q','exit') canvas = Canvas(root, width=WINDOW, height=.25*WINDOW, background='white') canvas.create_text(.1*WINDOW,.125*WINDOW,text=".33",font=("Helvetica", 24),tags="text",fill="#0000b0") canvas.create_rectangle(.2*WINDOW,.05*WINDOW,.3*WINDOW,.2*WINDOW, tags='rect1', fill='#b00000') canvas.create_rectangle(.3*WINDOW,.05*WINDOW,.9*WINDOW,.2*WINDOW, tags='rect2', fill='#0000b0') canvas.pack() root.after(100,idle,root,canvas) root.mainloop()