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@ttmarek
Created May 2, 2014 21:30
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Python script to read serial data from the Arduino
import serial
import csv
import re
import matplotlib.pyplot as plt
import pandas as pd
portPath = "/dev/ttyACM0" # Must match value shown on Arduino IDE
baud = 115200 # Must match Arduino baud rate
timeout = 5 # Seconds
filename = "data.csv"
max_num_readings = 16000
num_signals = 1
def create_serial_obj(portPath, baud_rate, tout):
"""
Given the port path, baud rate, and timeout value, creates
and returns a pyserial object.
"""
return serial.Serial(portPath, baud_rate, timeout = tout)
def read_serial_data(serial):
"""
Given a pyserial object (serial). Outputs a list of lines read in
from the serial port
"""
serial.flushInput()
serial_data = []
readings_left = True
timeout_reached = False
while readings_left and not timeout_reached:
serial_line = serial.readline()
if serial_line == '':
timeout_reached = True
else:
serial_data.append(serial_line)
if len(serial_data) == max_num_readings:
readings_left = False
return serial_data
def is_number(string):
"""
Given a string returns True if the string represents a number.
Returns False otherwise.
"""
try:
float(string)
return True
except ValueError:
return False
def clean_serial_data(data):
"""
Given a list of serial lines (data). Removes all characters.
Returns the cleaned list of lists of digits.
Given something like: ['0.5000,33\r\n', '1.0000,283\r\n']
Returns: [[0.5,33.0], [1.0,283.0]]
"""
clean_data = []
for line in data:
line_data = re.findall("\d*\.\d*|\d*",line) # Find all digits
line_data = [float(element) for element in line_data if is_number(element)] # Convert strings to float
if len(line_data) >= 2:
clean_data.append(line_data)
return clean_data
def save_to_csv(data, filename):
"""
Saves a list of lists (data) to filename
"""
with open(filename, 'wb') as csvfile:
csvwrite = csv.writer(csvfile)
csvwrite.writerows(data)
def gen_col_list(num_signals):
"""
Given the number of signals returns
a list of columns for the data.
E.g. 3 signals returns the list: ['Time','Signal1','Signal2','Signal3']
"""
col_list = ['Time']
for i in range(1,num_signals+1):
col = 'Signal'+str(i)
col_list.append(col)
return col_list
def map_value(x, in_min, in_max, out_min, out_max):
return (((x - in_min) * (out_max - out_min))/(in_max - in_min)) + out_min
def simple_plot(csv_file, columns, headers):
plt.clf()
plt.close()
plt.plotfile(csv_file, columns, names=headers, newfig=True)
plt.show()
def plot_csv(csv_file, cols):
# Create Pandas DataFrame from csv data
data_frame = pd.read_csv(csv_file)
# Set the names of the columns
data_frame.columns = cols
# Set the first column (Time) as the index
data_frame = data_frame.set_index(cols[0])
# Map the voltage values from 0-1023 to 0-5
data_frame = data_frame.apply(lambda x: map_value(x,0.,1023,0,5))
# Bring back the Time column
data_frame = data_frame.reset_index()
plt.clf()
plt.close()
# Plot the data
data_frame.plot(x=cols[0],y=cols[1:])
plt.show()
print "Creating serial object..."
serial_obj = create_serial_obj(portPath, baud, timeout)
print "Reading serial data..."
serial_data = read_serial_data(serial_obj)
print len(serial_data)
print "Cleaning data..."
clean_data = clean_serial_data(serial_data)
print "Saving to csv..."
save_to_csv(clean_data, filename)
print "Plotting data..."
#simple_plot(filename, (0,1,2), ['time (s)', 'voltage1', 'voltage2'])
#simple_plot(filename, (0,1), ['time (s)', 'voltage1'])
plot_csv(filename, gen_col_list(num_signals))
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