gravity snake game using arduino pressure sensor

live_plot_arduino.py

"""
Took the main functionality of this code from https://www.lebsanft.org/?p=48 
"""
import serial
import matplotlib
matplotlib.use('TkAgg')
import matplotlib.pyplot as plt 
import numpy as np 
import time
import sys
import exceptions

def plot_sensor(ymin, ymax, array_size=50, delay=100, test=False):
	"""
	min and max are the observed min and max values of the sensor.

	Here we assume that there is no delay built into arduino system
	"""
	bot_top_range=[25,40]
	yrange = ymax-ymin

	plt.ion()

	if test == False:
		port = '/dev/cu.usbserial-DA01LJJ1'
		other_important_number = 9600 

		ser = serial.Serial(port, other_important_number)
		dat_init = None 
		while dat_init == None:
			try:
				dat_init = float(ser.readline())
			except:
				e = sys.exc_info()[0] #want to catch all exceptions, but if we keyobard interrupt, exit! 
				if e != exceptions.KeyboardInterrupt:
					print("Problem getting initial data" + str(e))
				elif e == exceptions.ValueError:
					pass
				else:
					sys.exit()
		time_interval = time.time()
		for i in xrange(delay):
			ser.readline()
		time_interval = time.time() - time_interval
	elif test == True:
		dat_init = 0.0
		time_interval = 1.0
	
	difficulty = 0.3

	bot_width = np.random.randint(bot_top_range[0],bot_top_range[1])
	top_width = np.random.randint(bot_top_range[0],bot_top_range[1])
	bot_height = np.random.randint(int(yrange*difficulty))
	top_height = np.random.randint(int(yrange*difficulty))

	y_data = [dat_init]*int(array_size)
	y_prime = [0]*int(array_size)
	y_bot = [ymin + bot_height]*2*int(array_size)
	y_top = [ymax - top_height]*2*int(array_size)

	fig = plt.figure(figsize=(16,9))
	ax = fig.add_subplot(111)  
	line, = plt.plot(y_data)
	line_prime, = plt.plot(y_prime)
	line_bot, = plt.plot(y_bot, lw=3)
	line_top, = plt.plot(y_top, lw=3)

	line.set_xdata(np.arange(array_size)*time_interval)
	line_top.set_xdata(np.arange(2*array_size)*time_interval)
	line_bot.set_xdata(np.arange(2*array_size)*time_interval)
	plt.xlim([0,2*array_size])
	plt.ylim([ymin,ymax])
	plt.title("Snake game")
	counter_top = 0 
	counter_bottom = 0 
	grace_counter = 0
	deaths = 0
	grace_period = 15
	# plt.ylim([10,40])
	while True:  
		
		if test == False:
			data_array = np.arange(delay)
			for i in xrange(delay):
				try:
					val = ser.readline()
					# print(val)
					data_array[i] = float(val)
				except: 
					e = sys.exc_info()[0] #want to catch all exceptions, but if we keyobard interrupt, exit! 
					if e != exceptions.KeyboardInterrupt:
						print("Problem continuously reading data, Error: " + str(e))
						plt.draw()
					else:
						sys.exit()
			if data_array.shape[0] != delay:
				print("Looks like there was an error")

		elif test == True:
			data_array = np.zeros(delay)
			time.sleep(0.2)

		

		counter_top += 1
		counter_bottom += 1

		if counter_bottom == bot_width:
			bot_width = np.random.randint(bot_top_range[0],bot_top_range[1])
			bot_height = np.random.randint(int(yrange*difficulty))
			counter_bottom = 0
		if counter_top == top_width:
			top_width = np.random.randint(bot_top_range[0],bot_top_range[1])
			top_height = np.random.randint(int(yrange*difficulty))	
			counter_top = 0

		data = np.mean(data_array)

		if grace_counter < grace_period:
			grace_counter += 1
		elif grace_counter == grace_period:
			if data > (y_top[array_size-1]) or data < (y_bot[array_size-1]):
				deaths += 1
				plt.title("Snake Game, deaths = {}".format(deaths))


		y_data.append(data)
		y_data.pop(0)

		# y prime data 
		y_p = (y_data[-1] - y_data[-2]) / time_interval
		y_prime.append(y_p)
		y_prime.pop(0)

		y_top.append(ymax - top_height)
		y_top.pop(0)

		y_bot.append(ymin + bot_height)
		y_bot.pop(0)

		line.set_ydata(y_data) 
		line_top.set_ydata(y_top)
		line_bot.set_ydata(y_bot) 
		# line_prime.set_ydata(y_prime)

		plt.draw() # update the plot
			
		

if __name__ == '__main__':
	
	plot_sensor(0, 1024, delay=50, test=False)