From: sandyjmacdonald <sandyjmacdonald@gmail.com>
Date: Fri, 8 Nov 2019 20:26:45 +0000 (+0000)
Subject: Adding all in one weather and light display example
X-Git-Url: https://zdv2.bktei.com/gitweb/EVA-2020-02-2.git/commitdiff_plain/2fe226f8a1755e1cf487c972b56b9166b4f2ff4b?ds=sidebyside

Adding all in one weather and light display example
---

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diff --git a/examples/weather-and-light.py b/examples/weather-and-light.py
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+++ b/examples/weather-and-light.py
@@ -0,0 +1,409 @@
+import time
+import numpy
+import colorsys
+from PIL import Image, ImageDraw, ImageFont, ImageFilter
+from fonts.ttf import RobotoMedium as UserFont
+
+import ST7735
+from bme280 import BME280
+from ltr559 import LTR559
+
+import pytz
+from astral import Astral
+from datetime import datetime, timedelta
+
+try:
+    from smbus2 import SMBus
+except ImportError:
+    from smbus import SMBus
+
+
+def calculate_y_pos(x, centre):
+    """Calculates the y-coordinate on a parabolic curve, given x."""
+    centre = 80
+    y = 1 / centre * (x - centre) ** 2
+
+    return int(y)
+
+
+def circle_coordinates(x, y, radius):
+    """Calculates the bounds of a circle, given centre and radius."""
+
+    x1 = x - radius  # Left
+    x2 = x + radius  # Right
+    y1 = y - radius  # Bottom
+    y2 = y + radius  # Top
+
+    return (x1, y1, x2, y2)
+
+
+def map_colour(x, centre, start_hue, end_hue, day):
+    """Given an x coordinate and a centre point, a start and end hue (in degrees),
+       and a Boolean for day or night (day is True, night False), calculate a colour
+       hue representing the 'colour' of that time of day."""
+
+    start_hue = start_hue / 360  # Rescale to between 0 and 1
+    end_hue = end_hue / 360
+
+    sat = 1.0
+
+    # Dim the brightness as you move from the centre to the edges
+    val = 1 - (abs(centre - x) / (2 * centre))
+
+    # Ramp up towards centre, then back down
+    if x > centre:
+        x = (2 * centre) - x
+
+    # Calculate the hue
+    hue = start_hue + ((x / centre) * (end_hue - start_hue))
+
+    # At night, move towards purple/blue hues and reverse dimming
+    if not day:
+        hue = 1 - hue
+        val = 1 - val
+
+    r, g, b = [int(c * 255) for c in colorsys.hsv_to_rgb(hue, sat, val)]
+
+    return (r, g, b)
+
+
+def x_from_sun_moon_time(progress, period, x_range):
+    """Recalculate/rescale an amount of progress through a time period."""
+
+    x = int((progress / period) * x_range)
+
+    return x
+
+
+def sun_moon_time(dt, city_name, time_zone):
+    """Calculate the progress through the current sun/moon period (i.e day or
+       night) from the last sunrise or sunset, given a datetime object 't'."""
+
+    a = Astral()
+    city = a[city_name]
+
+    # Datetime objects for yesterday, today, tomorrow
+    today = dt.date()
+    dt = pytz.timezone(time_zone).localize(dt)
+    yesterday = today - timedelta(1)
+    tomorrow = today + timedelta(1)
+
+    # Sun objects for yesterfay, today, tomorrow
+    sun_yesterday = city.sun(date=yesterday, local=True)
+    sun = city.sun(date=today, local=True)
+    sun_tomorrow = city.sun(date=tomorrow, local=True)
+
+    # Work out sunset yesterday, sunrise/sunset today, and sunrise tomorrow
+    sunset_yesterday = sun_yesterday["sunset"]
+    sunrise_today = sun["sunrise"]
+    sunset_today = sun["sunset"]
+    sunrise_tomorrow = sun_tomorrow["sunrise"]
+
+    # Work out lengths of day or night period and progress through period
+    if sunrise_today < dt < sunset_today:
+        day = True
+        period = sunset_today - sunrise_today
+        mid = sunrise_today + (period / 2)
+        progress = dt - sunrise_today
+
+    elif dt > sunset_today:
+        day = False
+        period = sunrise_tomorrow - sunset_today
+        mid = sunset_today + (period / 2)
+        progress = dt - sunset_today
+
+    else:
+        day = False
+        period = sunrise_today - sunset_yesterday
+        mid = sunset_yesterday + (period / 2)
+        progress = dt - sunset_yesterday
+
+    # Convert time deltas to seconds
+    progress = progress.total_seconds()
+    period = period.total_seconds()
+
+    return (progress, period, day)
+
+
+def draw_background(progress, period, day):
+    """Given an amount of progress through the day or night, draw the
+       background colour and overlay a blurred sun/moon."""
+
+    # x-coordinate for sun/moon
+    x = x_from_sun_moon_time(progress, period, WIDTH)
+
+    # If it's day, then move right to left
+    if day:
+        x = WIDTH - x
+
+    # Calculate position on sun/moon's curve
+    centre = WIDTH / 2
+    y = calculate_y_pos(x, centre)
+
+    # Background colour
+    background = map_colour(x, 80, mid_hue, day_hue, day)
+
+    # New image for background colour
+    img = Image.new('RGBA', (WIDTH, HEIGHT), color=background)
+    draw = ImageDraw.Draw(img)
+
+    # New image for sun/moon overlay
+    overlay = Image.new('RGBA', (WIDTH, HEIGHT), color=(0, 0, 0, 0))
+    overlay_draw = ImageDraw.Draw(overlay)
+
+    # Draw the sun/moon
+    circle = circle_coordinates(x, y, sun_radius)
+    overlay_draw.ellipse(circle, fill=(200, 200, 50, opacity))
+
+    # Overlay the sun/moon on the background as an alpha matte
+    composite = Image.alpha_composite(img, overlay).filter(ImageFilter.GaussianBlur(radius=blur))
+
+    return composite
+
+
+def overlay_text(img, position, text, font, align_right=False, rectangle=False):
+    draw = ImageDraw.Draw(img)
+    w, h = font.getsize(text)
+    if align_right:
+        x, y = position
+        x -= w
+        position = (x, y)
+    if rectangle:
+        x += 1
+        y += 1
+        position = (x, y)
+        border = 1
+        rect = (x - border, y, x + w, y + h + border)
+        rect_img = Image.new('RGBA', (WIDTH, HEIGHT), color=(0, 0, 0, 0))
+        rect_draw = ImageDraw.Draw(rect_img)
+        rect_draw.rectangle(rect, (255, 255, 255))
+        rect_draw.text(position, text, font=font, fill=(0, 0, 0, 0))
+        img = Image.alpha_composite(img, rect_img)
+    else:
+        draw.text(position, text, font=font, fill=(255, 255, 255))
+    return img
+
+
+def get_cpu_temperature():
+    with open("/sys/class/thermal/thermal_zone0/temp", "r") as f:
+        temp = f.read()
+        temp = int(temp) / 1000.0
+    return temp
+
+
+def correct_humidity(humidity, temperature, corr_temperature):
+    dewpoint = temperature - ((100 - humidity) / 5)
+    corr_humidity = 100 - (5 * (corr_temperature - dewpoint))
+    return min(100, corr_humidity)
+
+
+def analyse_pressure(pressure, t):
+    global time_vals, pressure_vals, trend
+    if len(pressure_vals) > num_vals:
+        pressure_vals = pressure_vals[1:] + [pressure]
+        time_vals = time_vals[1:] + [t]
+
+        # Calculate line of best fit
+        line = numpy.polyfit(time_vals, pressure_vals, 1, full=True)
+
+        # Calculate slope, variance, and confidence
+        slope = line[0][0]
+        intercept = line[0][1]
+        variance = numpy.var(pressure_vals)
+        residuals = numpy.var([(slope * x + intercept - y)  for x, y in zip(time_vals, pressure_vals)])
+        r_squared = 1 - residuals / variance
+
+        # Calculate change in pressure per hour
+        change_per_hour = slope * 60 * 60
+        variance_per_hour = variance * 60 * 60
+
+        mean_pressure = numpy.mean(pressure_vals)
+
+        # Calculate trend
+        if r_squared > 0.5:
+            if change_per_hour > 0.5:
+                trend = ">"
+            elif change_per_hour < -0.5:
+                trend = "<"
+            elif -0.5 <= change_per_hour <= 0.5:
+                trend = "-"
+
+            if trend != "-":
+                if abs(change_per_hour) > 3:
+                    trend *= 2
+    else:
+        pressure_vals.append(pressure)
+        time_vals.append(t)
+        mean_pressure = numpy.mean(pressure_vals)
+        change_per_hour = 0
+        trend = "-"
+
+#    time.sleep(interval)
+
+    return (mean_pressure, change_per_hour, trend)
+
+def describe_pressure(pressure):
+    """Convert pressure into barometer-type description."""
+    if pressure < 970:
+        description = "storm"
+    elif 970 <= pressure < 990:
+        description = "rain"
+    elif 990 <= pressure < 1010:
+        description = "change"
+    elif 1010 <= pressure < 1030:
+        description = "fair"
+    elif pressure >= 1030:
+        description = "dry"
+    else:
+        description = ""
+    return description
+
+
+def describe_humidity(humidity):
+    """Convert relative humidity into good/bad description."""
+    if 40 < humidity < 60:
+        description = "good"
+    else:
+        description = "bad"
+    return description
+
+
+def describe_light(light):
+    """Convert light level in lux to descriptive value."""
+    if light < 50:
+        description = "dark"
+    elif 50 <= light < 100:
+        description = "dim"
+    elif 100 <= light < 500:
+        description = "light"
+    elif light >= 500:
+        description = "bright"
+    return description
+
+
+# Initialise the LCD
+disp = ST7735.ST7735(
+    port=0,
+    cs=1,
+    dc=9,
+    backlight=12,
+    rotation=270,
+    spi_speed_hz=10000000
+)
+
+disp.begin()
+
+WIDTH = disp.width
+HEIGHT = disp.height
+
+# The city and timezone that you want to display.
+city_name = "Sheffield"
+time_zone = "Europe/London"
+
+# Values that alter the look of the background
+blur = 50
+opacity = 125
+
+mid_hue = 0
+day_hue = 25
+
+sun_radius = 50
+
+# Fonts
+font_sm = ImageFont.truetype(UserFont, 12)
+font_lg = ImageFont.truetype(UserFont, 14)
+
+# Margins
+margin = 3
+
+dt = datetime.now()
+
+# Set up BME280 weather sensor
+bus = SMBus(1)
+bme280 = BME280(i2c_dev=bus)
+
+min_temp = bme280.get_temperature()
+max_temp = bme280.get_temperature()
+
+factor = 2.25
+cpu_temps = [get_cpu_temperature()] * 5
+
+# Set up light sensor
+ltr559 = LTR559()
+
+# Pressure variables
+pressure_vals = []
+time_vals = []
+num_vals = 1000
+interval = 1
+trend = "-"
+
+while True:
+    dt = datetime.now()
+#    dt += timedelta(minutes=5)
+    progress, period, day = sun_moon_time(dt, city_name, time_zone)
+    background = draw_background(progress, period, day)
+
+    # Time.
+    date_string = dt.strftime("%d %b %y").lstrip('0')
+    time_string = dt.strftime("%H:%M")
+    img = overlay_text(background, (0 + margin, 0 + margin), time_string, font_lg)
+    img = overlay_text(img, (WIDTH - margin, 0 + margin), date_string, font_lg, align_right=True)
+
+    # Temperature
+    temperature = bme280.get_temperature()
+
+    # Corrected temperature
+    cpu_temp = get_cpu_temperature()
+    cpu_temps = cpu_temps[1:] + [cpu_temp]
+    avg_cpu_temp = sum(cpu_temps) / float(len(cpu_temps))
+    corr_temperature = temperature - ((avg_cpu_temp - temperature) / factor)
+
+    if corr_temperature < min_temp:
+        min_temp = corr_temperature
+    elif corr_temperature > max_temp:
+        max_temp = corr_temperature
+
+    temp_string = f"{corr_temperature:.0f}°C"
+    img = overlay_text(img, (68, 18), temp_string, font_lg, align_right=True)
+    spacing = font_lg.getsize(temp_string)[1] + 1
+    range_string = f"{min_temp:.0f}-{max_temp:.0f}"
+    img = overlay_text(img, (68, 18 + spacing), range_string, font_sm, align_right=True, rectangle=True)
+    temp_icon = Image.open("icons/temperature.png")
+    img.paste(temp_icon, (margin, 18), mask=temp_icon)
+
+    # Humidity
+    humidity = bme280.get_humidity()
+    corr_humidity = correct_humidity(humidity, temperature, corr_temperature)
+    humidity_string = f"{corr_humidity:.0f}%"
+    img = overlay_text(img, (68, 48), humidity_string, font_lg, align_right=True)
+    spacing = font_lg.getsize(humidity_string)[1] + 1
+    humidity_desc = describe_humidity(corr_humidity).upper()
+    img = overlay_text(img, (68, 48 + spacing), humidity_desc, font_sm, align_right=True, rectangle=True)
+    humidity_icon = Image.open("icons/humidity-" + humidity_desc.lower() + ".png")
+    img.paste(humidity_icon, (margin, 48), mask=humidity_icon)
+
+    # Light
+    light = ltr559.get_lux()
+    light_string = f"{int(light):,}"
+    img = overlay_text(img, (WIDTH - margin, 18), light_string, font_lg, align_right=True)
+    spacing = font_lg.getsize(light_string.replace(",", ""))[1] + 1
+    light_desc = describe_light(light).upper()
+    img = overlay_text(img, (WIDTH - margin - 1, 18 + spacing), light_desc, font_sm, align_right=True, rectangle=True)
+    light_icon = Image.open("icons/bulb-" + light_desc.lower() +  ".png")
+    img.paste(humidity_icon, (80, 18), mask=light_icon)
+
+    # Pressure
+    pressure = bme280.get_pressure()
+    t = time.time()
+    mean_pressure, change_per_hour, trend = analyse_pressure(pressure, t)
+    pressure_string = f"{int(mean_pressure):,} {trend}"
+    img = overlay_text(img, (WIDTH - margin, 48), pressure_string, font_lg, align_right=True)
+    pressure_desc = describe_pressure(mean_pressure).upper()
+    spacing = font_lg.getsize(pressure_string.replace(",", ""))[1] + 1
+    img = overlay_text(img, (WIDTH - margin - 1, 48 + spacing), pressure_desc, font_sm, align_right=True, rectangle=True)
+    pressure_icon = Image.open("icons/weather-" + pressure_desc.lower() +  ".png")
+    img.paste(pressure_icon, (80, 48), mask=pressure_icon)
+
+    # Display image
+    disp.display(img)