1  # SPDX-FileCopyrightText: 2022 Liz Clark for Adafruit Industries
  2  # SPDX-License-Identifier: MIT
  3  
  4  import time
  5  import board
  6  import simpleio
  7  import adafruit_bmp280
  8  import pwmio
  9  import displayio
 10  from adafruit_motor import servo
 11  import terminalio
 12  from adafruit_clue import clue
 13  from adafruit_display_text import label
 14  
 15  #  pwm setup for servo
 16  pwm = pwmio.PWMOut(board.D0, duty_cycle=2 ** 15, frequency=50)
 17  gauge = servo.Servo(pwm)
 18  
 19  #  bmp280 sensor setup
 20  i2c = board.I2C()  # uses board.SCL and board.SDA
 21  bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)
 22  
 23  #  change depending on your location's elevation
 24  NOMINAL_PRESSURE = 1005.94
 25  
 26  PRESSURE_RANGE = 40 # hPa, expected pressure range variance caused by local weather
 27  PRESSURE_LOW_LIM = NOMINAL_PRESSURE - PRESSURE_RANGE
 28  PRESSURE_HIGH_LIM = NOMINAL_PRESSURE + PRESSURE_RANGE
 29  
 30  #  board display
 31  #  scaling for terminalio font
 32  display = board.DISPLAY
 33  group = displayio.Group(scale=3)
 34  
 35  #  text elements
 36  temp_header = "Temperature:"
 37  press_header = "Pressure:"
 38  temp_text = "   ºC"
 39  press_text = "   hPa"
 40  font = terminalio.FONT
 41  blue = 0x0000FF
 42  red = 0xFF0000
 43  
 44  #  temperature text elements
 45  temp_label = label.Label(font, text=temp_header, color=red, x=5, y=10)
 46  temp_data = label.Label(font, text=temp_text, color=red, x=5, y=25)
 47  
 48  #  pressure text elements
 49  press_label = label.Label(font, text=press_header, color=blue, x=5, y=50)
 50  press_data = label.Label(font, text=press_text, color=blue, x=5, y=65)
 51  
 52  #  adding text to display group
 53  group.append(temp_label)
 54  group.append(press_label)
 55  group.append(temp_data)
 56  group.append(press_data)
 57  
 58  display.show(group)
 59  
 60  #  function to convert celcius to fahrenheit
 61  def c_to_f(temp):
 62      temp_f = (temp * 9/5) + 32
 63      return temp_f
 64  
 65  #  function to convert hPa to inHg
 66  def hpa_to_inHg(hPa):
 67      inches_mercury = hPa * 0.02953
 68      return inches_mercury
 69  
 70  #  time.monotonic clock
 71  clock = 0
 72  #  units state
 73  metric_units = False
 74  
 75  while True:
 76      #  non-blocking 2 second delay
 77      if (clock + 2) < time.monotonic():
 78          #  map servo range to barometric pressure range
 79          servo_value = simpleio.map_range(bmp280.pressure,
 80                                           PRESSURE_LOW_LIM, PRESSURE_HIGH_LIM, 180, 0)
 81          #  set servo to pressure
 82          gauge.angle = servo_value
 83          #  print data for debugging
 84          print("\nTemperature: %0.1f C" % bmp280.temperature)
 85          print("Pressure: %0.1f hPa" % bmp280.pressure)
 86          print(servo_value)
 87          #  if metric units...
 88          if metric_units:
 89              #  update temp & pressure text in celcius and hPa
 90              temp_data.text = "%0.1f ºC" % bmp280.temperature
 91              press_data.text = "%0.1f hPa" % bmp280.pressure
 92          #  if imperial units...
 93          else:
 94              #  convert celcius to fahrenheit
 95              temp_fahrenheit = c_to_f(bmp280.temperature)
 96              #  convert hPa to inHg
 97              pressure_inHg = hpa_to_inHg(bmp280.pressure)
 98              #  update temp & pressure text
 99              temp_data.text = "%0.1f ºF" % temp_fahrenheit
100              press_data.text = "%0.1f inHg" % pressure_inHg
101          #  reset time.monotonic() clock
102          clock = time.monotonic()
103      #  if a button is pressed, metric_units is True, show metric
104      if clue.button_a:
105          metric_units = True
106      #  if b button is pressed, metric_units is False, show imperial units
107      if clue.button_b:
108          metric_units = False