ICA2 - GitPress.io

Example Python program ICA2.py Python version 3.x or newer. To check the Python version use:

python --version

Modules

import serial
import ringbuffer
import numpy as np
import time
import threading
import matplotlib
from matplotlib import animation
from matplotlib.lines import Line2D
from matplotlib import pyplot as plt

Methods

def read_serial_forever():
def init():
def animate(i):

Code

Python example

import serial
import ringbuffer
import numpy as np
import time
import threading
import matplotlib
#matplotlib.use('TKAgg')
from matplotlib import animation
from matplotlib.lines import Line2D
from matplotlib import pyplot as plt

BUFFER_SIZE = 500
data = ringbuffer.RingBuffer(BUFFER_SIZE)

serial_port = serial.Serial('/dev/cu.usbmodem14322', baudrate=57600, timeout=1)
serial_port.flush()

fig = plt.figure()

# setup the plot
# ax1 = fig.add_subplot(2, 1, 1)
# ax1.set_xlim(0, BUFFER_SIZE-1)
# ax1.set_ylim(-5, 300)
# line1 = Line2D([], [], color='red', linewidth=0.5)
# ax1.add_line(line1)

ax1 = plt.axes(xlim=(0, BUFFER_SIZE-1),ylim=(-5, 300))
line1 = Line2D([], [], color='red', linewidth=0.5)
ax1.add_line(line1)

print("before stuff goes down")

def read_serial_forever():
    global data
    while True:
        try:
            values = serial_port.read(1)
        except:
            print('Exiting thread')
            break

        if values:
            tmp = np.array(list(values))

            data.insert_new(tmp.astype(np.int))

            _min = np.min(data.get_samples)
            _max = np.max(data.get_samples)

            #print(_min, _max)

            if _min < 5 and _max > 250:
                print("touching")
            elif _min < 5: 
                print("touching and grounded")
            elif _min < 50:
                print("hovering")
            else:
                print("nothing")


t = threading.Thread(target=read_serial_forever, args=())
t.start()

# initialization, plot nothing (this is also called on resize)
def init():
    # called on first plot or redraw
    line1.set_data([], [])  # just draw blank background
    return line1,


# animation function.  This is called sequentially, after calling plt.show() (on main thread)
def animate(i):
    # generate some data to draw
    x = np.linspace(0, BUFFER_SIZE-1, BUFFER_SIZE)
    y = data.get_samples
    line1.set_data(x, y)
    # return line(s) to be drawn
    return line1,

# call the animator.  blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig,  # the figure to use
                               animate,  # the function to call
                               init_func=init,  # the function to init the drawing with
                               frames=BUFFER_SIZE,  # the max value of "i" in the animate function, before resetting
                               interval=20,  # 20 ms between each call
                               blit=False)  # do not redraw anything that stays the same between animations

plt.show()

serial_port.close() # will cause error, forcing close of thread
t.join() # wait for thread to exit

Useful Links

Articles: https://python-commandments.org/
Python shell: https://bsdnerds.org/learn-python/
Tutorial: https://pythonprogramminglanguage.com/