HomeGenie Forum

Automation Program Plugins and Wizard Scripting => Raspberry Pi GPIO/SPI/I2C => Topic started by: atom on March 30, 2016, 03:32:20 PM

Title: LCD 1602 PCF8574
Post by: atom on March 30, 2016, 03:32:20 PM

Hello everyone, trying to install LCD 1602 PCF8574 I2C, using the package "HD 44780 LCD PCF 8574" by changing the address on your "var address = 0x27", but it does not work, an error   `object' does not contain a definition for `Pins'

Title: Re: LCD 1602 PCF8574
Post by: bkenobi on March 30, 2016, 04:47:33 PM

I have no idea, but I would first search for where you are using "Pins" to see what it's referring to.  Perhaps it's expecting "Pins" and you aren't providing it so you won't find anything.

Title: Re: LCD 1602 PCF8574
Post by: atom on March 31, 2016, 09:14:57 AM

I also have a working script in Python, how to add it to HomeGenie?

Code: [Select]

#!/usr/bin/env python

import Adafruit_DHT as dht
import datetime
import time
import lcddriver

#Variables
sleepsecs = 30 #how many seconds to wait between each sensor query

lcd = lcddriver.lcd()

#Print welcome text on display
lcd.lcd_clear()
lcd.lcd_display_string("       Loading", 1)
lcd.lcd_display_string("   temperature and", 2)
lcd.lcd_display_string("     humidity log", 3)

#Write csv header
print "Datetime;Temp;Humidity"

#Function to "draw" a temperature or humidity bar on display
def draw_bar(value, line, low_limit, high_limit, bar_max_value):
char_width = 20 #display width in chars
bar_max_value = bar_max_value * 1.0

#Get character position for values
value_on_char = round(value / bar_max_value * char_width)
low_limit_on_char = round(low_limit / bar_max_value * char_width)
high_limit_on_char = round(high_limit / bar_max_value * char_width)

#Build string that comprises the bar
streng = ""
for i in range(0, char_width):
if i == value_on_char and (i > high_limit_on_char or i < low_limit_on_char):
streng = streng + "!"
elif i == value_on_char:
streng = streng + "*"
elif i > high_limit_on_char or i < low_limit_on_char:
streng = streng + "="
else:
streng = streng + "-"

#Write the bar to display on given line
lcd.lcd_display_string(streng, line)

#Main program loop
while True:
#Get current date and time
now = datetime.datetime.today().strftime('%Y-%m-%d %H:%M:%S')

#Read values from sensor
h,t = dht.read_retry(dht.DHT22, 4)

#Print date/time, temperature and humidity separated by semicolon
print now + ';{0:0.1f};{1:0.1f}'.format(t, h)

#Write temp, humidity to display
lcd.lcd_clear()
lcd.lcd_display_string("{0:0.1f} *C - {1:0.1f}%".format(t, h), 1)
#Draw temp, humidity bars to display
draw_bar(t, 2, 5, 21, 40) #temperature: value line low high bar_max
draw_bar(h, 3, 30, 50, 100) #humidity: value line low high bar_max
#Write date/time to display
lcd.lcd_display_string(now, 4)

#Wait sleepsecs seconds before repeating loop
time.sleep(sleepsecs)