Chart is being updated every 500 mseconds

software/smartwatch.py

 #Reference for Threading and GUI architecture: https://maldus512.medium.com/how-to-setup-correctly-an-application-with-python-and-tkinter-107c6bc5a45
+#Reference for function animate https://towardsdatascience.com/plotting-live-data-with-matplotlib-d871fac7500b
 import queue
 import tkinter as tk
 import matplotlib.pyplot as plt
@@ -6,6 +7,7 @@ import numpy as np
 
 from tkinter import TOP, BOTH, X, LEFT, RIGHT
 from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
+from matplotlib.animation import FuncAnimation
 from types import SimpleNamespace
 from enum import Enum
 from threading import Thread
@@ -35,7 +37,7 @@ def refreshUI(guiRef, model, guiQueue):
             pass 
 
         #Other tasks...
-        print("Han pasado 500 milisegundos")
+        #print("Han pasado 500 milisegundos")
 
 
 #Class for the User Interface
@@ -46,7 +48,11 @@ class Application(tk.Frame):
         #self.master.geometry('1000x1000')
         self.master.title('Smart Watch')
         self.pack(fill=BOTH, expand=True)
+        
+        #Animate needs to be created here and declared self. If not, will be gargabe collected
+        self.figure, self.ax = plt.subplots(1, 1, figsize=(6,5))
         self.create_widgets()
+        self.animate = FuncAnimation(self.figure, self.refreshChart, interval=500)
 
     def create_widgets(self):
     
@@ -60,20 +66,9 @@ class Application(tk.Frame):
     #FRAME 2 - GRAPH
         self.frame_two = tk.Frame(self.master)
         self.frame_two.pack(fill=X)
-
-        figure = plt.Figure(figsize=(6,5), dpi=100)
-        
-        ax = figure.add_subplot(111)
-        chart_type = FigureCanvasTkAgg(figure, self.frame_two)
+        chart_type = FigureCanvasTkAgg(self.figure, self.frame_two)
         chart_type.get_tk_widget().pack()
 
-        x = np.arange(10)
-        y = 2.5 * np.sin(x / 20 * np.pi)
-        ax.plot(x, y, color='tab:blue')
-        ax.set_xlim([0, 10])
-        ax.set_ylim([-1, 1])
-        ax.set_title('PPG - RED')
-
     #FRAME 3
         self.frame_three = tk.Frame(self.master)
         self.frame_three.pack(fill=X)
@@ -136,7 +131,6 @@ class Application(tk.Frame):
         
         print("Alarma HR!")
 
-
     #Method that provides reference to the user interface. It uses a queue to communicate the UI with the exterior. It returns references to 
     #inner objetcs so the exterior can communicate with it. More references can be given in "SimpleNameSpace"
     def gui_reference(self, root, queue):
@@ -152,6 +146,20 @@ class Application(tk.Frame):
         entry_two = self.entry_heartrate_minimum
         return SimpleNamespace(entry=entry, entry_two = entry_two)
 
+    #Function used to update the chart with external data. It is called every 500 mseconds. Data needs to be passed by reference using "gui_reference"
+    def refreshChart(self, x):
+        #get data
+        
+        x = np.arange(10)
+        y = 2.5 * np.sin(x / 20 * np.pi)
+        self.ax.plot(x, y, color='tab:blue')
+
+        print("Chart refreshed")
+        #set limits and title
+        self.ax.set_xlim([0, 10])
+        self.ax.set_ylim([-1, 1])
+        self.ax.set_title('PPG - RED') 
+
 if __name__ == '__main__':
 
     root = tk.Tk()