Chapter 10 follow behaviors

ch-10/3-wall-follow/pc/live_graph.py

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+""" Turn JSON data stream into graphs"""
+from itertools import count
+
+import requests
+
+import matplotlib.pyplot as plt
+from matplotlib.animation import FuncAnimation
+
+url = 'http://192.168.1.128'
+
+
+class SensorStream:
+  def __init__(self) -> None:
+      self.index = count()
+      self.error_values = []
+      self.sensor_values = []
+      self.pid_outputs = []
+      self.x_values = []
+
+      self.set_point = requests.get(f"{url}/set_point").json()
+
+  def sensor_stream(self):
+    item = requests.get(url).json()
+    print(f"Received: {item.decode('utf-8')}")
+    self.x_vals.append(next(self.index))
+    self.error_values.append(item['error_value'])
+    self.sensor_values.append(item['sensor_value'])
+    self.pid_outputs.append(item['pid_output'])
+
+    if len(self.x_vals) > 100:
+        self.x_vals = self.x_vals[-100:]
+        
+        self.error_values = self.error_values[-100:]
+        self.sensor_values = self.sensor_values[-100:]
+        self.pid_outputs = self.pid_outputs[-100:]
+
+    plt.cla() # clear axes.
+    # plot the items
+    plt.plot(self.x_vals, self.error_values, label="error")
+    plt.plot(self.x_vals, self.sensor_values, label="sensor")
+    plt.plot(self.x_vals, self.pid_outputs, label="pid")
+    
+    plt.legend(loc='upper right')
+
+  def start(self):
+    plt.style.use('fivethirtyeight')
+    # Create the animation. GFC - get current figure. random_stream - callback func.
+    self.ani = FuncAnimation(plt.gcf(), self.sensor_stream, interval=200)
+    plt.tight_layout()
+    plt.show()
+
+SensorStream().start()