examples/weather-and-light.py

   1 import time
   2 import numpy
   3 import colorsys
   4 from PIL import Image, ImageDraw, ImageFont, ImageFilter
   5 from fonts.ttf import RobotoMedium as UserFont
   6
   7 import ST7735
   8 from bme280 import BME280
   9 from ltr559 import LTR559
  10
  11 import pytz
  12 from astral import Astral
  13 from datetime import datetime, timedelta
  14
  15 try:
  16     from smbus2 import SMBus
  17 except ImportError:
  18     from smbus import SMBus
  19
  20
  21 def calculate_y_pos(x, centre):
  22     """Calculates the y-coordinate on a parabolic curve, given x."""
  23     centre = 80
  24     y = 1 / centre * (x - centre) ** 2
  25
  26     return int(y)
  27
  28
  29 def circle_coordinates(x, y, radius):
  30     """Calculates the bounds of a circle, given centre and radius."""
  31
  32     x1 = x - radius  # Left
  33     x2 = x + radius  # Right
  34     y1 = y - radius  # Bottom
  35     y2 = y + radius  # Top
  36
  37     return (x1, y1, x2, y2)
  38
  39
  40 def map_colour(x, centre, start_hue, end_hue, day):
  41     """Given an x coordinate and a centre point, a start and end hue (in degrees),
  42        and a Boolean for day or night (day is True, night False), calculate a colour
  43        hue representing the 'colour' of that time of day."""
  44
  45     start_hue = start_hue / 360  # Rescale to between 0 and 1
  46     end_hue = end_hue / 360
  47
  48     sat = 1.0
  49
  50     # Dim the brightness as you move from the centre to the edges
  51     val = 1 - (abs(centre - x) / (2 * centre))
  52
  53     # Ramp up towards centre, then back down
  54     if x > centre:
  55         x = (2 * centre) - x
  56
  57     # Calculate the hue
  58     hue = start_hue + ((x / centre) * (end_hue - start_hue))
  59
  60     # At night, move towards purple/blue hues and reverse dimming
  61     if not day:
  62         hue = 1 - hue
  63         val = 1 - val
  64
  65     r, g, b = [int(c * 255) for c in colorsys.hsv_to_rgb(hue, sat, val)]
  66
  67     return (r, g, b)
  68
  69
  70 def x_from_sun_moon_time(progress, period, x_range):
  71     """Recalculate/rescale an amount of progress through a time period."""
  72
  73     x = int((progress / period) * x_range)
  74
  75     return x
  76
  77
  78 def sun_moon_time(dt, city_name, time_zone):
  79     """Calculate the progress through the current sun/moon period (i.e day or
  80        night) from the last sunrise or sunset, given a datetime object 't'."""
  81
  82     a = Astral()
  83     city = a[city_name]
  84
  85     # Datetime objects for yesterday, today, tomorrow
  86     today = dt.date()
  87     dt = pytz.timezone(time_zone).localize(dt)
  88     yesterday = today - timedelta(1)
  89     tomorrow = today + timedelta(1)
  90
  91     # Sun objects for yesterfay, today, tomorrow
  92     sun_yesterday = city.sun(date=yesterday, local=True)
  93     sun = city.sun(date=today, local=True)
  94     sun_tomorrow = city.sun(date=tomorrow, local=True)
  95
  96     # Work out sunset yesterday, sunrise/sunset today, and sunrise tomorrow
  97     sunset_yesterday = sun_yesterday["sunset"]
  98     sunrise_today = sun["sunrise"]
  99     sunset_today = sun["sunset"]
 100     sunrise_tomorrow = sun_tomorrow["sunrise"]
 101
 102     # Work out lengths of day or night period and progress through period
 103     if sunrise_today < dt < sunset_today:
 104         day = True
 105         period = sunset_today - sunrise_today
 106         mid = sunrise_today + (period / 2)
 107         progress = dt - sunrise_today
 108
 109     elif dt > sunset_today:
 110         day = False
 111         period = sunrise_tomorrow - sunset_today
 112         mid = sunset_today + (period / 2)
 113         progress = dt - sunset_today
 114
 115     else:
 116         day = False
 117         period = sunrise_today - sunset_yesterday
 118         mid = sunset_yesterday + (period / 2)
 119         progress = dt - sunset_yesterday
 120
 121     # Convert time deltas to seconds
 122     progress = progress.total_seconds()
 123     period = period.total_seconds()
 124
 125     return (progress, period, day)
 126
 127
 128 def draw_background(progress, period, day):
 129     """Given an amount of progress through the day or night, draw the
 130        background colour and overlay a blurred sun/moon."""
 131
 132     # x-coordinate for sun/moon
 133     x = x_from_sun_moon_time(progress, period, WIDTH)
 134
 135     # If it's day, then move right to left
 136     if day:
 137         x = WIDTH - x
 138
 139     # Calculate position on sun/moon's curve
 140     centre = WIDTH / 2
 141     y = calculate_y_pos(x, centre)
 142
 143     # Background colour
 144     background = map_colour(x, 80, mid_hue, day_hue, day)
 145
 146     # New image for background colour
 147     img = Image.new('RGBA', (WIDTH, HEIGHT), color=background)
 148     draw = ImageDraw.Draw(img)
 149
 150     # New image for sun/moon overlay
 151     overlay = Image.new('RGBA', (WIDTH, HEIGHT), color=(0, 0, 0, 0))
 152     overlay_draw = ImageDraw.Draw(overlay)
 153
 154     # Draw the sun/moon
 155     circle = circle_coordinates(x, y, sun_radius)
 156     overlay_draw.ellipse(circle, fill=(200, 200, 50, opacity))
 157
 158     # Overlay the sun/moon on the background as an alpha matte
 159     composite = Image.alpha_composite(img, overlay).filter(ImageFilter.GaussianBlur(radius=blur))
 160
 161     return composite
 162
 163
 164 def overlay_text(img, position, text, font, align_right=False, rectangle=False):
 165     draw = ImageDraw.Draw(img)
 166     w, h = font.getsize(text)
 167     if align_right:
 168         x, y = position
 169         x -= w
 170         position = (x, y)
 171     if rectangle:
 172         x += 1
 173         y += 1
 174         position = (x, y)
 175         border = 1
 176         rect = (x - border, y, x + w, y + h + border)
 177         rect_img = Image.new('RGBA', (WIDTH, HEIGHT), color=(0, 0, 0, 0))
 178         rect_draw = ImageDraw.Draw(rect_img)
 179         rect_draw.rectangle(rect, (255, 255, 255))
 180         rect_draw.text(position, text, font=font, fill=(0, 0, 0, 0))
 181         img = Image.alpha_composite(img, rect_img)
 182     else:
 183         draw.text(position, text, font=font, fill=(255, 255, 255))
 184     return img
 185
 186
 187 def get_cpu_temperature():
 188     with open("/sys/class/thermal/thermal_zone0/temp", "r") as f:
 189         temp = f.read()
 190         temp = int(temp) / 1000.0
 191     return temp
 192
 193
 194 def correct_humidity(humidity, temperature, corr_temperature):
 195     dewpoint = temperature - ((100 - humidity) / 5)
 196     corr_humidity = 100 - (5 * (corr_temperature - dewpoint))
 197     return min(100, corr_humidity)
 198
 199
 200 def analyse_pressure(pressure, t):
 201     global time_vals, pressure_vals, trend
 202     if len(pressure_vals) > num_vals:
 203         pressure_vals = pressure_vals[1:] + [pressure]
 204         time_vals = time_vals[1:] + [t]
 205
 206         # Calculate line of best fit
 207         line = numpy.polyfit(time_vals, pressure_vals, 1, full=True)
 208
 209         # Calculate slope, variance, and confidence
 210         slope = line[0][0]
 211         intercept = line[0][1]
 212         variance = numpy.var(pressure_vals)
 213         residuals = numpy.var([(slope * x + intercept - y)  for x, y in zip(time_vals, pressure_vals)])
 214         r_squared = 1 - residuals / variance
 215
 216         # Calculate change in pressure per hour
 217         change_per_hour = slope * 60 * 60
 218         variance_per_hour = variance * 60 * 60
 219
 220         mean_pressure = numpy.mean(pressure_vals)
 221
 222         # Calculate trend
 223         if r_squared > 0.5:
 224             if change_per_hour > 0.5:
 225                 trend = ">"
 226             elif change_per_hour < -0.5:
 227                 trend = "<"
 228             elif -0.5 <= change_per_hour <= 0.5:
 229                 trend = "-"
 230
 231             if trend != "-":
 232                 if abs(change_per_hour) > 3:
 233                     trend *= 2
 234     else:
 235         pressure_vals.append(pressure)
 236         time_vals.append(t)
 237         mean_pressure = numpy.mean(pressure_vals)
 238         change_per_hour = 0
 239         trend = "-"
 240
 241 #    time.sleep(interval)
 242
 243     return (mean_pressure, change_per_hour, trend)
 244
 245 def describe_pressure(pressure):
 246     """Convert pressure into barometer-type description."""
 247     if pressure < 970:
 248         description = "storm"
 249     elif 970 <= pressure < 990:
 250         description = "rain"
 251     elif 990 <= pressure < 1010:
 252         description = "change"
 253     elif 1010 <= pressure < 1030:
 254         description = "fair"
 255     elif pressure >= 1030:
 256         description = "dry"
 257     else:
 258         description = ""
 259     return description
 260
 261
 262 def describe_humidity(humidity):
 263     """Convert relative humidity into good/bad description."""
 264     if 40 < humidity < 60:
 265         description = "good"
 266     else:
 267         description = "bad"
 268     return description
 269
 270
 271 def describe_light(light):
 272     """Convert light level in lux to descriptive value."""
 273     if light < 50:
 274         description = "dark"
 275     elif 50 <= light < 100:
 276         description = "dim"
 277     elif 100 <= light < 500:
 278         description = "light"
 279     elif light >= 500:
 280         description = "bright"
 281     return description
 282
 283
 284 # Initialise the LCD
 285 disp = ST7735.ST7735(
 286     port=0,
 287     cs=1,
 288     dc=9,
 289     backlight=12,
 290     rotation=270,
 291     spi_speed_hz=10000000
 292 )
 293
 294 disp.begin()
 295
 296 WIDTH = disp.width
 297 HEIGHT = disp.height
 298
 299 # The city and timezone that you want to display.
 300 city_name = "Sheffield"
 301 time_zone = "Europe/London"
 302
 303 # Values that alter the look of the background
 304 blur = 50
 305 opacity = 125
 306
 307 mid_hue = 0
 308 day_hue = 25
 309
 310 sun_radius = 50
 311
 312 # Fonts
 313 font_sm = ImageFont.truetype(UserFont, 12)
 314 font_lg = ImageFont.truetype(UserFont, 14)
 315
 316 # Margins
 317 margin = 3
 318
 319 dt = datetime.now()
 320
 321 # Set up BME280 weather sensor
 322 bus = SMBus(1)
 323 bme280 = BME280(i2c_dev=bus)
 324
 325 min_temp = bme280.get_temperature()
 326 max_temp = bme280.get_temperature()
 327
 328 factor = 2.25
 329 cpu_temps = [get_cpu_temperature()] * 5
 330
 331 # Set up light sensor
 332 ltr559 = LTR559()
 333
 334 # Pressure variables
 335 pressure_vals = []
 336 time_vals = []
 337 num_vals = 1000
 338 interval = 1
 339 trend = "-"
 340
 341 while True:
 342     dt = datetime.now()
 343 #    dt += timedelta(minutes=5)
 344     progress, period, day = sun_moon_time(dt, city_name, time_zone)
 345     background = draw_background(progress, period, day)
 346
 347     # Time.
 348     date_string = dt.strftime("%d %b %y").lstrip('0')
 349     time_string = dt.strftime("%H:%M")
 350     img = overlay_text(background, (0 + margin, 0 + margin), time_string, font_lg)
 351     img = overlay_text(img, (WIDTH - margin, 0 + margin), date_string, font_lg, align_right=True)
 352
 353     # Temperature
 354     temperature = bme280.get_temperature()
 355
 356     # Corrected temperature
 357     cpu_temp = get_cpu_temperature()
 358     cpu_temps = cpu_temps[1:] + [cpu_temp]
 359     avg_cpu_temp = sum(cpu_temps) / float(len(cpu_temps))
 360     corr_temperature = temperature - ((avg_cpu_temp - temperature) / factor)
 361
 362     if corr_temperature < min_temp:
 363         min_temp = corr_temperature
 364     elif corr_temperature > max_temp:
 365         max_temp = corr_temperature
 366
 367     temp_string = f"{corr_temperature:.0f}°C"
 368     img = overlay_text(img, (68, 18), temp_string, font_lg, align_right=True)
 369     spacing = font_lg.getsize(temp_string)[1] + 1
 370     range_string = f"{min_temp:.0f}-{max_temp:.0f}"
 371     img = overlay_text(img, (68, 18 + spacing), range_string, font_sm, align_right=True, rectangle=True)
 372     temp_icon = Image.open("icons/temperature.png")
 373     img.paste(temp_icon, (margin, 18), mask=temp_icon)
 374
 375     # Humidity
 376     humidity = bme280.get_humidity()
 377     corr_humidity = correct_humidity(humidity, temperature, corr_temperature)
 378     humidity_string = f"{corr_humidity:.0f}%"
 379     img = overlay_text(img, (68, 48), humidity_string, font_lg, align_right=True)
 380     spacing = font_lg.getsize(humidity_string)[1] + 1
 381     humidity_desc = describe_humidity(corr_humidity).upper()
 382     img = overlay_text(img, (68, 48 + spacing), humidity_desc, font_sm, align_right=True, rectangle=True)
 383     humidity_icon = Image.open("icons/humidity-" + humidity_desc.lower() + ".png")
 384     img.paste(humidity_icon, (margin, 48), mask=humidity_icon)
 385
 386     # Light
 387     light = ltr559.get_lux()
 388     light_string = f"{int(light):,}"
 389     img = overlay_text(img, (WIDTH - margin, 18), light_string, font_lg, align_right=True)
 390     spacing = font_lg.getsize(light_string.replace(",", ""))[1] + 1
 391     light_desc = describe_light(light).upper()
 392     img = overlay_text(img, (WIDTH - margin - 1, 18 + spacing), light_desc, font_sm, align_right=True, rectangle=True)
 393     light_icon = Image.open("icons/bulb-" + light_desc.lower() +  ".png")
 394     img.paste(humidity_icon, (80, 18), mask=light_icon)
 395
 396     # Pressure
 397     pressure = bme280.get_pressure()
 398     t = time.time()
 399     mean_pressure, change_per_hour, trend = analyse_pressure(pressure, t)
 400     pressure_string = f"{int(mean_pressure):,} {trend}"
 401     img = overlay_text(img, (WIDTH - margin, 48), pressure_string, font_lg, align_right=True)
 402     pressure_desc = describe_pressure(mean_pressure).upper()
 403     spacing = font_lg.getsize(pressure_string.replace(",", ""))[1] + 1
 404     img = overlay_text(img, (WIDTH - margin - 1, 48 + spacing), pressure_desc, font_sm, align_right=True, rectangle=True)
 405     pressure_icon = Image.open("icons/weather-" + pressure_desc.lower() +  ".png")
 406     img.paste(pressure_icon, (80, 48), mask=pressure_icon)
 407
 408     # Display image
 409     disp.display(img)