I am pretty much a beginner and although I've been using the Raspberry Pi for a few years I've never written my own Python scripts.
Here is my problem; I am building a temperature monitoring system with 4 DS18B20 waterproof sensors. I have the sensors working fine and they all output accurate data. I also have a 20x4 LCD on the I2C bus which is configured and working OK. What I don't know how to do is add the 4 temperatures, to 4 separate lines on the LCD.
My code is below and the temperatures need to be in lines 84 to 87. I am also having problems working out how to pull the IP address and hostname of the device.
Code: Select all
import smbus import time # Define some device parameters I2C_ADDR = 0x27 # I2C device address, if any error, change this address to 0x3f LCD_WIDTH = 20 # Maximum characters per line # Define some device constants LCD_CHR = 1 # Mode - Sending data LCD_CMD = 0 # Mode - Sending command LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line LCD_BACKLIGHT = 0x08 # On #LCD_BACKLIGHT = 0x00 # Off ENABLE = 0b00000100 # Enable bit # Timing constants E_PULSE = 0.0005 E_DELAY = 0.0005 #Open I2C interface #bus = smbus.SMBus(0) # Rev 1 Pi uses 0 bus = smbus.SMBus(1) # Rev 2 Pi uses 1 def lcd_init(): # Initialise display lcd_byte(0x33,LCD_CMD) # 110011 Initialise lcd_byte(0x32,LCD_CMD) # 110010 Initialise lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size lcd_byte(0x01,LCD_CMD) # 000001 Clear display time.sleep(E_DELAY) def lcd_byte(bits, mode): # Send byte to data pins # bits = the data # mode = 1 for data # 0 for command bits_high = mode | (bits & 0xF0) | LCD_BACKLIGHT bits_low = mode | ((bits<<4) & 0xF0) | LCD_BACKLIGHT # High bits bus.write_byte(I2C_ADDR, bits_high) lcd_toggle_enable(bits_high) # Low bits bus.write_byte(I2C_ADDR, bits_low) lcd_toggle_enable(bits_low) def lcd_toggle_enable(bits): # Toggle enable time.sleep(E_DELAY) bus.write_byte(I2C_ADDR, (bits | ENABLE)) time.sleep(E_PULSE) bus.write_byte(I2C_ADDR,(bits & ~ENABLE)) time.sleep(E_DELAY) def lcd_string(message,line): # Send string to display message = message.ljust(LCD_WIDTH," ") lcd_byte(line, LCD_CMD) for i in range(LCD_WIDTH): lcd_byte(ord(message[i]),LCD_CHR) def main(): # Main program block # Initialise display lcd_init() while True: # Send some test lcd_string("Out Temp:" ,LCD_LINE_1) lcd_string("In Temp: ",LCD_LINE_2) lcd_string("RX Temp: ",LCD_LINE_3) lcd_string("VRS Temp: ",LCD_LINE_4) time.sleep(3) # Send some more text lcd_string("Time: %s" %time.strftime("%H:%M"),LCD_LINE_1) lcd_string("Date: %s" %time.strftime("%d/%m/%Y"),LCD_LINE_2) lcd_string(" IP:" ,LCD_LINE_3) lcd_string("Host:",LCD_LINE_4) time.sleep(3) if __name__ == '__main__': try: main() except KeyboardInterrupt: pass finally: lcd_byte(0x01, LCD_CMD)