[Issue #2] - Added config.py toggle for observing daylight savings time

README.md

@@ -41,13 +41,13 @@ These are not necessary to run the app, but can be useful for testing and/or fla
 1. Connect your SSD1306 display to your Pico.
 2. Connect your Pico to your PC via a micro-USB to USB type-A cable.
 3. [Flash your Raspberry Pi Pico with MicroPython](https://docs.micropython.org/en/latest/rp2/tutorial/reset.html).
-  a. This has been tested with MicroPython 1.29, but other versions should work.
+    1. This has been tested with MicroPython 1.29, but other versions should work.
 4. Clone this git repository: `git clone https://git.metaunix.net/BitGoblin/pico-time`.
 5. `cd` into the repo: `cd pico-time`.
 6. Copy `config.example.py` to `config.py` and edit the settings to match your environment.
 7. Copy the Python code over to the Pico:
-  a. `mpremote cp main.py :main.py`
-  b. `mpremote cp config.py :config.py`
+    1. `mpremote cp main.py :main.py`
+    2. `mpremote cp config.py :config.py`
 8. Reset the Pico: `mpremote reset`
 
 If it worked you should see the display show a message about connecting to WiFi, then syncing time and finally displaying the local time. If it failed, you can monitor the app via `mpremote repl` or using an IDE like [Thonny](https://thonny.org/).

config.example.py

@@ -2,5 +2,7 @@
 WIFI_SSID = "YourSSID"  # Set this to your Wi-Fi network name
 WIFI_PASSWORD = "YourPassword"  # Set this to your Wi-Fi network password
 
-# Timezone settings
+# Time settings
+USE_24_HOUR = False  # Set this to True for 24-hour time (no AM/PM)
 UTC_OFFSET = -5  # Set this to your desired NTP server
+DST_OBSERVED = True  # Set this to false if you don't observe Daylight Savings Time

main.py

@@ -1,3 +1,4 @@
+import framebuf
 import network
 import ntptime
 import time
@@ -51,21 +52,129 @@ except Exception as e:
 # Disconnect Wi-Fi to conserve power once time is synchronized
 wlan.active(False)
 
+
+def draw_scaled_text(display, text, x, y, scale=2):
+    """
+    Renders text scaled up by an integer factor (scale=2 -> 16x16, scale=3 -> 24x24).
+    Uses a temporary 1-bit FrameBuffer to capture the default 8x8 font.
+    """
+    width = len(text) * 8
+    height = 8
+
+    # 1-bit MONO_HLSB buffer: (width * height) / 8 bytes
+    buf = bytearray((width * height) // 8)
+    fb = framebuf.FrameBuffer(buf, width, height, framebuf.MONO_HLSB)
+
+    # Render string with built-in font into the scratch buffer
+    fb.fill(0)
+    fb.text(text, 0, 0, 1)
+
+    # Read each pixel and draw a (scale x scale) block on the OLED
+    for r in range(height):
+        for c in range(width):
+            if fb.pixel(c, r):
+                display.fill_rect(x + (c * scale), y + (r * scale), scale, scale, 1)
+
+
+def calculate_x_spacing(text, scale=1):
+    """
+    Calculates the amount of horizontal (x) spacing is needed to center a string.
+    """
+    scaled_text = len(text) * scale
+    return (128 - (scaled_text * 8)) // 2
+
+
+def is_dst(year, month, day, hour_utc, weekday):
+    """
+    Returns True if UTC time falls within US/Canada Daylight Saving Time:
+    - Starts: 2nd Sunday in March at 02:00 local (07:00 UTC for UTC-5)
+    - Ends:   1st Sunday in November at 02:00 local (06:00 UTC for UTC-4)
+    Note: weekday is 0=Monday ... 6=Sunday.
+    """
+    if not Config.DST_OBSERVED:
+        return False
+
+    # 1. Months completely inside or outside DST
+    if month < 3 or month > 11:
+        return False
+    if 3 < month < 11:
+        return True
+
+    # 2. March (Starts 2nd Sunday)
+    # The 2nd Sunday always falls between March 8 and March 14
+    if month == 3:
+        # Find the day of the 2nd Sunday
+        second_sunday = 14 - ((weekday - day + 14) % 7)
+        if day < second_sunday:
+            return False
+        elif day > second_sunday:
+            return True
+        else:
+            # On the transition day itself, 02:00 EST is 07:00 UTC
+            return hour_utc >= 7
+
+    # 3. November (Ends 1st Sunday)
+    # The 1st Sunday always falls between Nov 1 and Nov 7
+    if month == 11:
+        first_sunday = 7 - ((weekday - day + 7) % 7)
+        if day < first_sunday:
+            return True
+        elif day > first_sunday:
+            return False
+        else:
+            # On the transition day itself, 02:00 EDT (01:00 EST) is 06:00 UTC
+            return hour_utc < 6
+
+    return False
+
+
 # --- Main Loop ---
 DAYS = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
+TIME_Y = 12  # Keep vertical placement consistent
+
+last_second = -1
 
 while True:
-    # Apply UTC offset to local epoch
-    local_epoch = time.time() + (Config.UTC_OFFSET * 3600)
-    year, month, day, hour, minute, second, weekday, _ = time.localtime(local_epoch)
+    # 1. Fast, single-integer read from RTC
+    current_sec = time.time()
 
-    time_str = f"{hour:02d}:{minute:02d}:{second:02d}"
-    date_str = f"{DAYS[weekday]} {year}-{month:02d}-{day:02d}"
+    # 2. Gate everything behind the 1-second boundary
+    if current_sec != last_second:
+        last_second = current_sec
 
-    oled.fill(0)
-    # Center-align roughly for 8x8 font
-    oled.text(time_str, 32, 20)
-    oled.text(date_str, 12, 38)
-    oled.show()
+        # Unpack UTC once per second
+        utc_year, utc_month, utc_day, utc_hour, _, _, utc_weekday, _ = time.gmtime(current_sec)
 
-    time.sleep(0.5)
+        # Run DST check
+        dst_offset = 1 if is_dst(utc_year, utc_month, utc_day, utc_hour, utc_weekday) else 0
+        total_offset = Config.UTC_OFFSET + dst_offset
+
+        # Compute local wall-clock components
+        local_epoch = current_sec + (total_offset * 3600)
+        year, month, day, hour_24, minute, second, weekday, _ = time.localtime(local_epoch)
+
+        # --- String formatting and OLED rendering ---
+        sep = ":" if second % 2 == 0 else " "
+
+        if Config.USE_24_HOUR:
+            time_str = f"{hour_24:02d}{sep}{minute:02d}"
+            period = None
+        else:
+            hour_12 = hour_24 % 12 or 12
+            time_str = f"{hour_12}{sep}{minute:02d}"
+            period = "AM" if hour_24 < 12 else "PM"
+
+        oled.fill(0)
+        time_x = calculate_x_spacing(time_str, scale=2)
+        draw_scaled_text(oled, time_str, x=time_x, y=TIME_Y, scale=2)
+
+        if period:
+            oled.text(period, time_x + (len(time_str) * 16) + 4, TIME_Y + 8)
+
+        date_str = f"{DAYS[weekday]} {year}-{month:02d}-{day:02d}"
+        oled.text(date_str, calculate_x_spacing(date_str), 42)
+
+        oled.show()
+
+    # Fast poll to catch the next second boundary immediately
+    time.sleep_ms(25)