serialtest.py

# from time import sleep
# import serial
# ser = serial.Serial('COM3', 9600) # Establish the connection on a specific port
# res = ser.read()
# print(res)
import serial

import time
import csv
import matplotlib
matplotlib.use("tkAgg")
import matplotlib.pyplot as plt
import numpy as np

ser = serial.Serial('COM3')
ser.flushInput()

plot_window = 20
y_var = np.array(np.zeros([plot_window]))

plt.ion()
fig, ax = plt.subplots()
line, = ax.plot(y_var)

while True:
    try:
        ser_bytes = ser.readline()
        try:
            decoded_bytes = float(ser_bytes[0:len(ser_bytes)-2].decode("utf-8"))
            print(decoded_bytes)
        except:
            continue
        with open("test_data.csv","a") as f:
            writer = csv.writer(f,delimiter=",")
            writer.writerow([time.time(),decoded_bytes])
        if decoded_bytes < 0.0:
            y_var = np.append(y_var,0)
        else:
            y_var = np.append(y_var,decoded_bytes)
        y_var = y_var[1:plot_window+1]
        line.set_ydata(y_var)
        ax.relim()
        ax.autoscale_view()
        fig.canvas.draw()
        fig.canvas.flush_events()
    except:
        print("Keyboard Interrupt")
        break