Merge pull request #704 from caternuson/pp_iss_tracker

Add PyPortal ISS Tracker code

Author: ladyada

PyPortal_ISS_Tracker/map.bmp

@@ -0,0 +1,126 @@
+import time
+import math
+import board
+import displayio
+from terminalio import FONT
+from adafruit_pyportal import PyPortal
+from adafruit_display_shapes.circle import Circle
+from adafruit_display_text.label import Label
+
+#--| USER CONFIG |--------------------------
+MARK_SIZE = 10           # marker radius
+MARK_COLOR = 0xFF3030    # marker color
+MARK_THICKNESS = 5       # marker thickness
+TRAIL_LENGTH = 200       # trail length
+TRAIL_COLOR = 0xFFFF00   # trail color
+DATE_COLOR = 0x111111    # date color
+TIME_COLOR = 0x111111    # time color
+LAT_MAX = 80             # latitude (deg) of map top/bottom edge
+UPDATE_RATE = 10         # update rate in seconds
+#-------------------------------------------
+
+DATA_SOURCE = "http://api.open-notify.org/iss-now.json"
+DATA_LOCATION = ["iss_position"]
+
+WIDTH = board.DISPLAY.width
+HEIGHT = board.DISPLAY.height
+
+# determine the current working directory needed so we know where to find files
+cwd = ("/"+__file__).rsplit('/', 1)[0]
+pyportal = PyPortal(url=DATA_SOURCE,
+                    json_path=DATA_LOCATION,
+                    status_neopixel=board.NEOPIXEL,
+                    default_bg=cwd+"/map.bmp")
+
+# Connect to the internet and get local time
+pyportal.get_local_time()
+
+# Date and time label
+date_label = Label(FONT, text="0000-00-00", color=DATE_COLOR, x=165, y=223)
+time_label = Label(FONT, text="00:00:00", color=TIME_COLOR, x=240, y=223)
+pyportal.splash.append(date_label)
+pyportal.splash.append(time_label)
+
+# ISS trail
+trail_bitmap = displayio.Bitmap(3, 3, 1)
+trail_palette = displayio.Palette(1)
+trail_palette[0] = TRAIL_COLOR
+trail = displayio.Group(max_size=TRAIL_LENGTH)
+pyportal.splash.append(trail)
+
+# ISS location marker
+marker = displayio.Group(max_size=MARK_THICKNESS)
+for r in range(MARK_SIZE - MARK_THICKNESS, MARK_SIZE):
+    marker.append(Circle(0, 0, r, outline=MARK_COLOR))
+pyportal.splash.append(marker)
+
+def get_location(width=WIDTH, height=HEIGHT):
+    """Fetch current lat/lon, convert to (x, y) tuple scaled to width/height."""
+
+    # Get location
+    try:
+        location = pyportal.fetch()
+    except RuntimeError:
+        return None, None
+
+    # Compute (x, y) coordinates
+    lat = float(location["latitude"])   # degrees, -90 to 90
+    lon = float(location["longitude"])  # degrees, -180 to 180
+
+    # Scale latitude for cropped map
+    lat *= 90 / LAT_MAX
+
+    # Mercator projection math
+    # https://stackoverflow.com/a/14457180
+    # https://en.wikipedia.org/wiki/Mercator_projection#Alternative_expressions
+    x = lon + 180
+    x = width * x / 360
+
+    y = math.radians(lat)
+    y = math.tan(math.pi / 4 + y / 2)
+    y = math.log(y)
+    y = (width * y) / (2 * math.pi)
+    y = height / 2 - y
+
+    return int(x), int(y)
+
+def update_display(current_time, update_iss=False):
+    """Update the display with current info."""
+
+    # ISS location
+    if update_iss:
+        x, y = get_location()
+        if x and y:
+            marker.x = x
+            marker.y = y
+            if len(trail) >= TRAIL_LENGTH:
+                trail.pop(0)
+            trail.append(displayio.TileGrid(trail_bitmap,
+                                            pixel_shader=trail_palette,
+                                            x = x - 1,
+                                            y = y - 1) )
+
+
+    # Date and time
+    date_label.text = "{:04}-{:02}-{:02}".format(current_time.tm_year,
+                                                 current_time.tm_mon,
+                                                 current_time.tm_mday)
+    time_label.text = "{:02}:{:02}:{:02}".format(current_time.tm_hour,
+                                                 current_time.tm_min,
+                                                 current_time.tm_sec)
+
+    board.DISPLAY.refresh_soon()
+
+# Initial refresh
+update_display(time.localtime(), True)
+last_update = time.monotonic()
+
+# Run forever
+while True:
+    now = time.monotonic()
+    new_position = False
+    if now - last_update > UPDATE_RATE:
+        new_position = True
+        last_update = now
+    update_display(time.localtime(), new_position)
+    time.sleep(0.5)