monitor_wq.py

#! /usr/bin/env python
from time import sleep
import RPi.GPIO as GPIO 
import lcd_functions as lf
import psycopg2
import ds18b20
from datetime import datetime


def get_cursor():

    """get database cursor"""

    conn = psycopg2.connect(database="postgres",
                            user="postgres",
                            password="apassword",
                            host="192.168.0.104") 

    conn.autocommit = True
    cur = conn.cursor()

    return cur


def get_weather(cur):

    """returns most recent temperature"""
    
    cur.execute("""SELECT condition -> 'current_observation' -> 'temp_f' 
                   FROM arlington_weather_condition
                   WHERE id = (SELECT MAX(id) 
                               FROM arlington_weather_condition
                               WHERE condition -> 'current_observation' ->> 'temp_f' != '')""")


    temp = [i[0] for i in cur][0]

    return temp


def get_forecast(cur):

    """returns most recent forecast"""
    
    cur.execute("""SELECT forecast -> 'forecast' -> 'simpleforecast' -> 'forecastday' 
                    FROM arlington_weather_forecast 
                    WHERE id = (SELECT MAX(id) 
                                FROM arlington_weather_forecast);""")

    data = [i[0] for i in cur][0][0]

    low = str(data['low']['fahrenheit'])
    high = str(data['high']['fahrenheit'])

    return low, high


def get_inside(cur):

    """returns most recent inside temperature"""
    
    cur.execute("""SELECT temp 
                    FROM inside_temp 
                    WHERE id = (SELECT MAX(id) 
                                FROM inside_temp);""")

    temp = str([i for i in cur][0][0])

    return temp


def pick_color(temp):

    """returns color name based on temp"""

    if temp >= 90.0:
        color = 'red'
    elif temp < 90.0 and temp >= 80.0:
        color = 'yellow'
    elif temp < 80.0 and temp >= 70.0:
        color = 'green'
    elif temp < 70.0 and temp >= 60.0:
        color = 'cyan'
    elif temp < 60.0 and temp >= 50.0:
        color = 'blue'
    else:
        color = 'white'

    return color


def monitor(wait=60):
    """continuous print latest temp to lcd"""

    try:

        # get lcd object
        lcd = lf.lcd

        # continuously read sensors
        while True:

            # get database cursor
            cur = get_cursor()

            # get inside temp
            inside = get_inside(cur)

            # get the latest temp
            temp = get_weather(cur)
            
            # get low/high
            low, high = get_forecast(cur)

            # pick background color based on temp
            temp_color = pick_color(temp)

            # create string to print to screen
            temp_str = "In:{} Out:{}\n High:{} Low:{} ".format(inside, temp, high, low)
                
            # display temp on LCD and set RGB color based on temp
            lf.display_text(temp_str, color=temp_color)

            # print temp to screen
            print(temp_str)
                
            # wait n seconds
            sleep(wait)
    
    except Exception, e:
        print(str(e))

    finally:
        lcd.clear()
        GPIO.cleanup()


if __name__ == '__main__':
    monitor()