7-seg display temp value fix, read_raw_temp shrink, python3 compat, tested, linted

Author: Mikey Sklar

Large-Pi-Based-Thermometer-Clock/README.md

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+# Large-Pi-Based-Thermometer-Clock
+
+Code to accompany this tutorial:
+https://learn.adafruit.com/large-pi-based-thermometer-and-clock

Large-Pi-Based-Thermometer-Clock/thermo_clock.py

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+import glob
+import time
+import datetime
+from Adafruit_LED_Backpack import SevenSegment
+import board
+import digitalio
+
+switch_pin = digitalio.DigitalInOut(board.D18)
+switch_pin.direction = digitalio.Direction.INPUT
+switch_pin.pull = digitalio.Pull.UP
+
+segment = SevenSegment.SevenSegment(address=0x70)
+# Initialize the display. Must be called once before using the display.
+segment.begin()
+
+base_dir = '/sys/bus/w1/devices/'
+device_folder = glob.glob(base_dir + '28*')[0]
+device_file = device_folder + '/w1_slave'
+
+def read_temp_raw():
+    f = open(device_file, 'r')
+    lines = f.readlines()
+    f.close()
+    return lines
+
+def read_temp():
+    lines = read_temp_raw()
+    while lines[0].strip()[-3:] != 'YES':
+        time.sleep(0.2)
+        lines = read_temp_raw()
+    equals_pos = lines[1].find('t=')
+    if equals_pos != -1:
+        temp_string = lines[1][equals_pos+2:]
+        temp_c = float(temp_string) / 1000.0
+        temp_f = temp_c * 9.0 / 5.0 + 32.0
+        return temp_c, temp_f
+
+def display_temp():
+    segment.set_colon(False)
+    temp = int(read_temp()[1]) # F
+#   temp = int(read_temp()[0]) # C
+    sign = (temp < 0)
+    temp = abs(temp)
+    digit_1 = int(temp % 10)
+    temp = temp / 10
+    digit_2 = int(temp % 10)
+    temp = temp / 10
+    digit_3 = int(temp % 10)
+    if sign :
+        segment.set_digit_raw(0, 0x40)      # - sign
+    if digit_3 > 0 :
+        segment.set_digit(0, digit_3)       # Hundreds
+    else:
+        segment.set_digit_raw(0, 0)
+    if digit_2 > 0 :
+        segment.set_digit(1, digit_2)       # Tens
+    else:
+        segment.set_digit_raw(1, 0)
+    segment.set_digit(2, digit_1)           # Ones
+    segment.set_digit_raw(3, 0x71) #F       # Temp units letter
+#   segment.set_digit_raw(3, 0x39) #C
+
+def display_time():
+    now = datetime.datetime.now()
+    hour = now.hour
+    minute = now.minute
+    second = now.second
+    # Set hours
+    segment.set_digit(0, int(hour / 10))        # Tens
+    segment.set_digit(1, hour % 10)             # Ones
+    # Set minutes
+    segment.set_digit(2, int(minute / 10))      # Tens
+    segment.set_digit(3, minute % 10)           # Ones
+    # Toggle colon
+    segment.set_colon(second % 2)               # Toggle colon at 1Hz
+
+
+while True:
+    segment.clear()
+    if not switch_pin.value:
+        display_temp()
+    else :
+        display_time()
+    segment.write_display()
+    time.sleep(0.5)