#!/usr/bin/env python2.7 """Handle messages from Node-RED and display them on the LCD""" # Topic: Send message to 20x4 LCD # # file : LCD20x4-I2C.py import time import threading import json import sys import math import lcddriver if len(sys.argv) == 5: CMD = sys.argv[1].lower() LCD_TYPE = sys.argv[2].lower() SCROLL_SPEED = int(sys.argv[3]) lcddriver.ADDRESS = int(sys.argv[4], 16) lcd_error = False; try: LCD = lcddriver.lcd() except: print "LCD Not Found - Check Addess and Connections" lcd_error = True; if (not lcd_error): STARTUPMSG = [" SYSTEM ", " START ", " UP ", " "] SHUTDOWNMSG = [" SYSTEM ", " SHUT ", " DOWN ", " "] ERRORMSG = [" ERROR ", " DETECTED ", " ", " "] CLS = [" ", " ", " ", " "] def translate(value, left_min, left_max, right_min, right_max): """Translate string (handles scrolling effect)""" global UPDATE_SCREEN_THREAD_STOP if (left_min > left_max or right_min > right_max or value < left_min or value > left_max or not isinstance(value, (int, long, float, complex))): if not isinstance(value, (int, long, float, complex)): error = "Scroll Speed Value NaN" else: error = "Scroll Speed Value Error" updatescreen(ERRORMSG, SCROLL_SPEED, UPDATE_SCREEN_THREAD_STOP) print error return False else: left_span = left_max - left_min right_span = right_max - right_min value_scaled = float(value - left_min) / float(left_span) return right_min + (value_scaled * right_span) def updatescreen(input_msg, sleep, stop_event): """Send message to screen""" sleep = translate(sleep, 1, 10, 0.1, 2) #update this range to affect scroll speed if not sleep: return messages = [input_msg[0], input_msg[1], input_msg[2], input_msg[3]] scrollinglines = [] for number in range(0, 4): if len(messages[number]) > 20: truncated = messages[number][:19] + "*" scrollinglines.append(number) else: truncated = messages[number] + " "*(20 - len(messages[number])) LCD.lcd_display_string(truncated, number+1) time.sleep(0.05) while (not stop_event.is_set() and scrollinglines): for line in scrollinglines: LCD.lcd_display_string(messages[line][:19] + "*", line+1) time.sleep(sleep*1.5) for character in range(1, len(messages[line])-18): if stop_event.is_set(): break if character >= len(messages[line]) - 19: truncated = "*" + messages[line][character:character+19] else: truncated = "*" + messages[line][character:character+18] + "*" LCD.lcd_display_string(truncated, line+1) time.sleep(sleep) if stop_event.is_set(): for reset_line in range(0, 4): LCD.lcd_display_string(" "*20, reset_line+1) break else: time.sleep(sleep*1.5) UPDATE_SCREEN_THREAD_STOP = threading.Event() UPDATE_SCREEN_THREAD = threading.Thread(target=updatescreen, args=(STARTUPMSG, SCROLL_SPEED, UPDATE_SCREEN_THREAD_STOP)) UPDATE_SCREEN_THREAD.start() def pad_str(pos, input_str): """Pad leading spaces if pos has a value""" global UPDATE_SCREEN_THREAD_STOP if (isinstance(input_str, basestring) and isinstance(pos, (int, long, float, complex)) and pos > 0 and pos <= 20): input_str = " "*(pos-1) + input_str return input_str else: if not isinstance(input_str, basestring): error = "Message not a String" if not isinstance(pos, (int, long, float, complex)): error = "Message Position NaN" elif (pos < 1 or pos >= 20): error = "Message Position not 1-20" updatescreen(ERRORMSG, SCROLL_SPEED, UPDATE_SCREEN_THREAD_STOP) print error return False def center_str(input_str): """Center the string based on length""" if isinstance(input_str, basestring): pad = int(math.floor(((20-len(input_str))/2))) input_str = " "*(pad) + input_str return input_str else: print "Message not a String" return False def main(): """main function""" global UPDATE_SCREEN_THREAD global UPDATE_SCREEN_THREAD_STOP if sys.version_info >= (3, 0): print "Sorry - currently only configured to work with python 2.x" sys.exit(1) if CMD == "writelcd": if LCD_TYPE == "20x4": while True: try: data = raw_input() if data == 'close': if UPDATE_SCREEN_THREAD.isAlive(): UPDATE_SCREEN_THREAD_STOP.set() while UPDATE_SCREEN_THREAD.isAlive(): time.sleep(0.05) updatescreen(SHUTDOWNMSG, SCROLL_SPEED, UPDATE_SCREEN_THREAD_STOP) sys.exit(0) else: if UPDATE_SCREEN_THREAD.isAlive(): UPDATE_SCREEN_THREAD_STOP.set() while UPDATE_SCREEN_THREAD.isAlive(): time.sleep(0.05) json_error = False #speederror = False poserror = False centererror = False try: data = json.loads(data) except: print "Input not a JSON Message" json_error = True if not json_error: msg = [] for line in range(0, 4): try: if data['msgs'][line]['center'] is True: if len(data['msgs'][line]['msg']) < 21: msg.append(center_str(data['msgs'][line]['msg'])) if not msg[line]: centererror = True break else: msg.append(data['msgs'][line]['msg']) else: raise KeyError except KeyError: try: msg.append(pad_str(data['msgs'][line]['pos'], data['msgs'][line]['msg'])) if not msg[line]: poserror = True except KeyError: print "POS or msg Value Missing" poserror = True break if not poserror and not centererror: UPDATE_SCREEN_THREAD_STOP = threading.Event() UPDATE_SCREEN_THREAD = threading.Thread(target=updatescreen, args=(msg, SCROLL_SPEED, UPDATE_SCREEN_THREAD_STOP)) UPDATE_SCREEN_THREAD.start() else: updatescreen(ERRORMSG, 3, UPDATE_SCREEN_THREAD_STOP) else: updatescreen(ERRORMSG, 3, UPDATE_SCREEN_THREAD_STOP) except (EOFError, KeyboardInterrupt): if UPDATE_SCREEN_THREAD.isAlive(): UPDATE_SCREEN_THREAD_STOP.set() while UPDATE_SCREEN_THREAD.isAlive(): time.sleep(0.05) updatescreen(SHUTDOWNMSG, 3, UPDATE_SCREEN_THREAD_STOP) sys.exit(0) except SystemExit: if UPDATE_SCREEN_THREAD.isAlive(): UPDATE_SCREEN_THREAD_STOP.set() while UPDATE_SCREEN_THREAD.isAlive(): time.sleep(0.05) updatescreen(SHUTDOWNMSG, 3, UPDATE_SCREEN_THREAD_STOP) sys.exit(0) else: print "Bad parameters - accepts writelcd {screensize}" if __name__ == '__main__': main()