c.py

# To easilly transfer the generated data between the ARM and the PC do the following:
# 
# In your pc:
#   nc -l -p 2999 > received.json
#
# In the arm
#   tail -f /tmp/data/miavita.json | nc 192.168.0.1 2999

import numpy as np
import matplotlib.pyplot as plt

# the scatter plot:
axScatter = plt.subplot(2, 1, 1)

f = open("/tmp/received.json")

delta_l = []
a_l = []
b_l = []
c_l = []
d_l = []
time_l = []

import pdb

last_ts = -1
for l in f.readlines():

    try:
        # seq = int(l.split('"')[2][1:-1])
        timestamp = int(l.split('"')[4][1:-1])
        channel_a = int(l.split('"')[6][1:-1])
        channel_b = int(l.split('"')[8][1:-1])
        channel_c = int(l.split('"')[10][1:-1])
        channel_d = int(l.split('"')[12][1:-2])
    except:
        continue

    if last_ts == -1:
        delta_time = 0

    else:
        delta_time = timestamp - last_ts

    last_ts = timestamp

    delta_l.append(delta_time)
    time_l.append(timestamp)
    a_l.append(channel_a)
    b_l.append(channel_b)
    c_l.append(channel_c)
    d_l.append(channel_d)


axScatter.scatter(time_l, a_l, s=2, color='r', label='ch1')
axScatter.scatter(time_l, b_l, s=2, color='c', label='ch2')
axScatter.scatter(time_l, c_l, s=2, color='y', label='ch3')
axScatter.scatter(time_l, d_l, s=2, color='g', label='ch4')
plt.legend()
plt.title("Channels Values")

time_plot = plt.subplot(2, 1, 2)
time_plot.plot(time_l, delta_l, c='r', label='x')
plt.title("Timestamp deltas")

plt.draw()
plt.show()