Merge pull request #465 from adafruit/Drive_a_16x2_LCD_with_the_Raspberry_Pi

Drive a 16x2 lcd with the raspberry pi

Drive_a_16x2_LCD_with_the_Raspberry_Pi/Drive_a_16x2_LCD_with_the_Raspberry_Pi.py

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+from subprocess import Popen, PIPE
+from time import sleep
+from datetime import datetime
+import board
+import digitalio
+import adafruit_character_lcd.character_lcd as characterlcd
+
+# Modify this if you have a different sized character LCD
+lcd_columns = 16
+lcd_rows = 2
+
+# compatible with all versions of RPI as of Jan. 2019
+# v1 - v3B+
+lcd_rs = digitalio.DigitalInOut(board.D22)
+lcd_en = digitalio.DigitalInOut(board.D17)
+lcd_d4 = digitalio.DigitalInOut(board.D25)
+lcd_d5 = digitalio.DigitalInOut(board.D24)
+lcd_d6 = digitalio.DigitalInOut(board.D23)
+lcd_d7 = digitalio.DigitalInOut(board.D18)
+
+
+# Initialise the lcd class
+lcd = characterlcd.Character_LCD_Mono(lcd_rs, lcd_en, lcd_d4, lcd_d5, lcd_d6,
+                                      lcd_d7, lcd_columns, lcd_rows)
+
+# looking for an active Ethernet or WiFi device
+def find_interface():
+    find_device = "ip addr show"
+    interface_parse = run_cmd(find_device)
+    for line in interface_parse.splitlines():
+        if "state UP" in line:
+            dev_name = line.split(':')[1]
+    return dev_name
+
+# find an active IP on the first LIVE network device
+def parse_ip():
+    find_ip = "ip addr show %s" % interface
+    find_ip = "ip addr show %s" % interface
+    ip_parse = run_cmd(find_ip)
+    for line in ip_parse.splitlines():
+        if "inet " in line:
+            ip = line.split(' ')[5]
+            ip = ip.split('/')[0]
+    return ip
+
+# run unix shell command, return as ASCII
+def run_cmd(cmd):
+    p = Popen(cmd, shell=True, stdout=PIPE)
+    output = p.communicate()[0]
+    return output.decode('ascii')
+
+# wipe LCD screen before we start
+lcd.clear()
+
+# before we start the main loop - detect active network device and ip address
+sleep(2)
+interface = find_interface()
+ip_address = parse_ip()
+
+while True:
+
+    # date and time
+    lcd_line_1 = datetime.now().strftime('%b %d  %H:%M:%S\n')
+
+    # current ip address
+    lcd_line_2 = "IP " + ip_address
+
+    # combine both lines into one update to the display
+    lcd.message = lcd_line_1 + lcd_line_2
+
+    sleep(2)

Drive_a_16x2_LCD_with_the_Raspberry_Pi/README.md

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+# Drive_a_16x2_LCD_with_the_Raspberry_Pi
+
+Code to accompany this tutorial:
+https://learn.adafruit.com/drive-a-16x2-lcd-directly-with-a-raspberry-pi

Drive_a_16x2_LCD_with_the_Raspberry_Pi/lcd.service

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+[Unit]
+Description=LCD date|time|ip
+Requires=network-online.target
+After=network-online.target
+
+[Service]
+ExecStart=/usr/bin/python3 Drive_a_16x2_LCD_with_the_Raspberry_Pi.py
+WorkingDirectory=/home/pi
+StandardOutput=inherit
+StandardError=inherit
+Restart=always
+User=pi
+
+[Install]
+WantedBy=network-online.target