#!/usr/bin/python # -*- coding: iso-8859-15 -*- ''' Bandsaw Tension Application Parts: 1ea - Raspberry Pi Zero V1.2 1ea - Phidgets - 3141_0 - Button Load Cell (0-1000kg) - CZL204 1ea - HX711 Weighing Pressure Sensor 24 Bit Precision AD Module For Arduino 1ea - MCP23008 - 8-Bit I/O Expander with High-speed I2C interface 1ea - 4x4 Matrix keypad 1ea - Serial I2C 20X4 Character LCD Module Display Modules: hx711.py - Source: https://github.com/tatobari/hx711py/blob/master/hx711.py keypad16.py - original from http://Mikronauts.com but modified by me to support MCP23008 RPi_I2C_driver.py - Source: https://gist.github.com/DenisFromHR/cc863375a6e19dce359d Date: November 15, 2016 By: Stephen B. Kirby ''' import RPi.GPIO as GPIO import RPi_I2C_driver import time import sys import os import json import signal import keypad16 as matrix from hx711 import HX711 # Load configuration from config JSON file. with open('config.json', 'r') as infile: config = json.load(infile) # calculate Area AREA = config['blade_width'] * config['blade_thickness'] * 2 # Key functions dictionary ''' KEY_FUNCTION = { "A": "blade_dimension", "B": "tare_menu", "C": "display_tension", "D": "display_force", # D - also used in tare_menu option "#": "main_menu"} ''' KEY_FUNCTION = { "A": "display_tension", "B": "display_force", "C": "display_settings", "D": "shutdown_pi", # D - also used in tare_menu option "#": "main_menu"} # Superscript two - squared Character fontdata0 = [[ 0b00100, 0b01010, 0b00110, 0b01000, 0b01110, 0b00000, 0b00000, 0b00000 ]] # HX711(dout, sck) - initialize Load Cell amplifier hx = HX711(5, 6) # initialize keypad and MCP23008 kp = matrix.keypad_module(0x20,0,0) # initialize the LCD disp = RPi_I2C_driver.lcd() disp.lcd_clear() # Clear display # According to the HX711 Datasheet, the second parameter is MSB so you shouldn't need to modify it. hx.set_reading_format("LSB", "MSB") # Set Reference unit for Phidgets Part: 3141_0 - Button Load Cell (0-1000kg) - CZL204 hx.set_reference_unit(config['calibration_factor']) # Reset and set offset for the HX711 amplifier board hx.reset() hx.set_offset(config['offset']) # set the offset # Shutdown Raspberry Pi def shutdown_pi(lbs, klg, ch, row = 2): save_data() # save data file disp.lcd_clear() # clear LCD time.sleep(0.1) disp.backlight(0) # turn OFF LED time.sleep(0.1) GPIO.cleanup() # cleanup GPIO os.system('shutdown now -h') # Event handler for Ctrl+C def signal_handler(signal, frame): # print 'You pressed Ctrl+C!' clean_and_exit() # save data to config.json data file def save_data(): with open('config.json', 'w') as outfile: json.dump(config, outfile) # save the data, cleanup GPIO and exit def clean_and_exit(): save_data() # save data file disp.lcd_clear() # clear LCD time.sleep(0.1) disp.backlight(0) # turn OFF LED time.sleep(0.1) GPIO.cleanup() # cleanup GPIO sys.exit() #exit python to system # Display Weight on LCD def display_LbKg(lbs, klg, ch, row = 2): # WEIGHT - Lbs and Klg if config['imperial_units']: disp.lcd_display_string_pos("Lb: ",row,0) disp.lcd_display_string_pos("{:10.1f}".format(lbs),row,10) else: disp.lcd_display_string_pos("Kg: ",row,0) disp.lcd_display_string_pos("{:10.1f}".format(klg),row,10) # Display TENSION on LCD - PSI and Kilo Pascals def display_PsikPa(lbs, klg, ch, row = 2): if config['imperial_units']: # PSI tension = lbs/AREA disp.lcd_display_string_pos("PSI: ",row,0) disp.lcd_display_string_pos("{:6.0f}".format(tension),row,14) else: disp.lcd_load_custom_chars(fontdata0) # load Superscript 2 - squared # kilograms per square centimeter tension = klg/AREA disp.lcd_display_string_pos("Kg/cm",row,0) disp.lcd_write_char(0) # print Superscript 2 - squared disp.lcd_display_string_pos(": ",row,6) disp.lcd_display_string_pos("{:6.0f}".format(tension),row,14) # Main Displays for LCD def main_menu(lbs, klg, ch): disp.lcd_display_string_pos("Tension: A",1,0) disp.lcd_display_string_pos("Force: B",2,0) disp.lcd_display_string_pos("Settings: C",3,0) disp.lcd_display_string_pos("Shutdown: D",4,0) def display_settings(lbs, klg, ch): disp.lcd_display_string_pos("SETTINGS ",1,0) disp.lcd_display_string_pos("Blade Dimension: A",2,0) disp.lcd_display_string_pos("Tare Scale: B",3,0) disp.lcd_display_string_pos("Menu: #",4,0) def display_force(lbs, klg, ch): disp.lcd_display_string_pos("FORCE ",1,0) display_LbKg(lbs, klg, ch) disp.lcd_display_string_pos("Menu: #",4,0) def display_tension(lbs, klg, ch): # display the Width x Thickness of Blade disp.lcd_display_string_pos("TENSION {:0.3f}x{:0.3f}".format(config['blade_width'],config['blade_thickness']),1,0) display_PsikPa(lbs, klg, ch, 2) disp.lcd_display_string_pos("Menu: #",4,0) def tare_menu(lbs, klg, ch): disp.lcd_display_string_pos("TARE SCALE ",1,0) display_LbKg(lbs, klg, ch) disp.lcd_display_string_pos("Tare: D Menu: #",4,0) # function called from TARE SCALE menu to TARE scale without a blade def tare_scale(lbs, klg, ch): global config, menu_item disp.lcd_display_string_pos("Saving Tare...",2,2) hx.reset() hx.tare() config['offset'] = hx.OFFSET # read and store the OFFSET save_data() # save the new OFFSET to config.json data file menu_item = tare_menu # return to the TARE SCALE menu # clear screen disp.lcd_clear() def blade_dimension(lbs, klg, ch): if config['imperial_units']: title = "BLADE DIMENSION - in" else: title = "BLADE DIMENSION - cm" disp.lcd_display_string_pos(title,1,0) disp.lcd_display_string_pos("Width: {:0.3f}".format(config['blade_width']),2,0) disp.lcd_display_string_pos("Thickness: {:0.3f}".format(config['blade_thickness']),3,0) disp.lcd_display_string_pos("W: 1 T: 2 Menu: #",4,0) def input_blade_width(lbs, klg, ch): if config['imperial_units']: title = "BLADE WIDTH - in" else: title = "BLADE WIDTH - cm" disp.lcd_display_string_pos(title,1,0) disp.lcd_display_string_pos("Current W: {:0.3f}".format(config['blade_width']),2,0) disp.lcd_display_string_pos("Width: {}".format(menu_variable),3,0) disp.lcd_display_string_pos("Save: A Cancel: #",4,0) def input_blade_thickness(lbs, klg, ch): if config['imperial_units']: title = "BLADE THICKNESS - in" else: title = "BLADE THICKNESS - cm" disp.lcd_display_string_pos(title,1,0) disp.lcd_display_string_pos("Current T: {:0.3f}".format(config['blade_thickness']),2,0) disp.lcd_display_string_pos("Thickness: {}".format(menu_variable),3,0) disp.lcd_display_string_pos("Save: A Cancel: #",4,0) # convert menu_variable string to number def num(s): if s == "": return 0 try: return int(s) except ValueError: return float(s) # Determine the menu function to call. menu_item = globals().get(KEY_FUNCTION['#'], display_tension) menu_variable = "" # check for keypad events def check_keypad_events(chk): if (chk != None): global menu_item, menu_variable, config, AREA # Input for menu options if chk in 'ABCD#': # Check for blade dimension input - 'A' = Save settings if (menu_item == input_blade_width) and (chk == "A"): config['blade_width'] = num(menu_variable) AREA = config['blade_width'] * config['blade_thickness'] * 2 save_data() # save the new blade_width to config.json data file if (menu_item == input_blade_thickness) and (chk == "A"): config['blade_thickness'] = num(menu_variable) AREA = config['blade_width'] * config['blade_thickness'] * 2 save_data() # save the new blade_thickness to config.json data file # Check for TARE SCALE input if (menu_item == tare_menu) and (chk == "D"): menu_item = tare_scale # SETTINGS MENU: # A = blade_dimension, B = tare_menu, # = main_menu if (menu_item == display_settings) and ((chk == "A") or (chk == "B")): if (chk == "A"): menu_item = blade_dimension if (chk == "B"): menu_item = tare_menu # MAIN MENU: # A = display_tension, B = display_force, C = display_settings # D = shutdown_pi, # = main_menu elif (menu_item == main_menu): menu_item = globals().get(KEY_FUNCTION[chk], display_tension) elif (chk == "#"): # if in blade width or Thickness menu then return to blade_dimension menu if (menu_item == input_blade_width) or (menu_item == input_blade_thickness): menu_item = blade_dimension else: # return to main_menu menu_item = main_menu # clear screen, set menu_item and reset menu_variable disp.lcd_clear() # reset the menu_variable menu_variable = "" # check for '1' kep stroke in 'blade_dimension' menu # change menu to Blade Width elif (menu_item == blade_dimension) and (chk == "1"): disp.lcd_clear() menu_item = globals().get('input_blade_width') menu_variable = "" # check for '2' kep stroke in 'blade_dimension' menu # change menu to Blade Thickness elif (menu_item == blade_dimension) and (chk == "2"): disp.lcd_clear() menu_item = globals().get('input_blade_thickness') menu_variable = "" else: # Input numeric data and store in menu_variable if chk == "*": # convert * to decimal point chk = "." # check for a decimal point in menu_variable - only one per value if (chk == ".") and ("." not in menu_variable): menu_variable += chk else: menu_variable += chk # Main loop: signal.signal(signal.SIGINT, signal_handler) # print 'Press Ctrl+C' while True: # Prints the weight. Comment if you're debbuging the MSB and LSB issue. val = hx.get_weight(1) if (val < 0): val = 0 # convert to kilograms kilos = val * 0.453592 # Check for key strokes on keypad key = kp.getkey() time.sleep(0.1) # check for Keypad events check_keypad_events(key) # call function menu_item(val, kilos, key) # power down and power up the HX711 hx.power_down() hx.power_up()