Working etch-a-sketch for the plotter, controlled by BrainJr.

etchASketch_forPlotter.py

import pygame
from pygame.locals import *
from pygame import midi
from colors import *

import chiplotle

import sys
import time
import random

import thread
import Queue


# Initialize Pygame --------------------
pygame.init()
windowX = 800
windowY = 800
window = pygame.display.set_mode((windowX, windowY))
pygame.display.set_caption('PenPlotter')


# Initialize Pygame Midi --------------------
midi.init()
count = midi.get_count()


# Prints all midi devices
for i in xrange(0, count):
	print i, midi.get_device_info(x)

# Sets midi input to device 0 (should be 'BrainJr Controls')
midi_in = midi.Input(0)



# Initialize the Plotter --------------------
plotter = chiplotle.instantiate_plotters()[0]


# Pygame helper functions --------------------
def clear():
	window.fill((255, 255, 255))

def input(events):
	for event in events:
		if event.type == QUIT:
			pygame.quit()
			sys.exit()


# Plotter functions --------------------

# Queue of plotter commands
q = Queue.Queue()

def send_to_plotter(m, n):
	while True:
		if q.qsize() > 0:
			print "WRITING TO PLOTTER"
			plotter.write(q.get())

# Start plotter thread ((None, None), is needed because args needs a tuple)
thread.start_new_thread(send_to_plotter, (None, None))


# Other helper functions --------------------
def scale(val, in_min, in_max, out_min, out_max):
	in_span = in_max - in_min
	out_span = out_max - out_min

	unitized = float(val - in_min) / float(in_span)
	return out_min + (unitized * out_span)


# Initialize variables--------------------
left_pot = 0
right_pot = 0

last_pt = (0, 0)

pointlist = ""


# Pick up pen
plotter.write('SP6;')


# Start main thread --------------------
clear()
while True:

	# Read 4 blocks of midi data at a time
	# Below, we'll read msg[0], essentially taking every fourth message. This helps reduce latency.
	msg = midi_in.read(4)

	if msg != []:

		# Button
		if msg[0][0][0] == 144:
			# Left
			if msg[0][0][1] == 1:
				# Off
				if msg[0][0][2] == 0:
					pass
				# On
				if msg[0][0][2] == 64:
					print "LEFT!"
					clear()
			# Right
			if msg[0][0][1] == 16:
				# Off
				if msg[0][0][2] == 0:
					pass
				# On
				if msg[0][0][2] == 64:
					print "RIGHT!"
					clear()

		# Potentiometer
		if msg[0][0][0] == 176:
			# Left
			if msg[0][0][1] == 1:
				left_pot = msg[0][0][2]
			# Right
			if msg[0][0][1] == 16:
				right_pot = 127 - msg[0][0][2]


	# Changes deltaX by value of left pot
	x += int(scale(left_pot, 0, 127, -5, 5))
	print x

	# x = int(scale(left_pot, 0, 127, 0, windowX))

	y = int(scale(right_pot, 0, 127, 0, windowY))

	# Add plotter command to string
	pointlist += 'PD' + str(y * 20 - 8000) + ',' + str(x * 20 - 8000) + ';'

	pygame.draw.line(window, BLACK, last_pt, (x, y), 2)
	last_pt = (x, y)

	# When the pointlist has more than n characters, put the string in the queue, then reset the string.
	if len(pointlist) > 500:
		print "sending points"
		q.put_nowait(pointlist)
		pointlist = ""

	pygame.display.flip()
	# clear()
	input(pygame.event.get())