Merge pull request #2301 from adafruit/servo_barometer

Updating CLUE barometer

Author: TheKitty

CLUE_Servo_Barometer/code.py

@@ -12,6 +12,21 @@
 from adafruit_clue import clue
 from adafruit_display_text import label
 
+#  pwm setup for servo
+pwm = pwmio.PWMOut(board.D0, duty_cycle=2 ** 15, frequency=50)
+gauge = servo.Servo(pwm)
+
+#  bmp280 sensor setup
+i2c = board.I2C()  # uses board.SCL and board.SDA
+bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)
+
+#  change depending on your location's elevation
+NOMINAL_PRESSURE = 1005.94
+
+PRESSURE_RANGE = 40 # hPa, expected pressure range variance caused by local weather
+PRESSURE_LOW_LIM = NOMINAL_PRESSURE - PRESSURE_RANGE
+PRESSURE_HIGH_LIM = NOMINAL_PRESSURE + PRESSURE_RANGE
+
 #  board display
 #  scaling for terminalio font
 display = board.DISPLAY
@@ -26,16 +41,6 @@
 blue = 0x0000FF
 red = 0xFF0000
 
-#  pwm setup for servo
-pwm = pwmio.PWMOut(board.D0, duty_cycle=2 ** 15, frequency=50)
-gauge = servo.Servo(pwm)
-
-#  bmp280 sensor setup
-i2c = board.I2C()  # uses board.SCL and board.SDA
-bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)
-
-bmp280.sea_level_pressure = 1013.25
-
 #  temperature text elements
 temp_label = label.Label(font, text=temp_header, color=red, x=5, y=10)
 temp_data = label.Label(font, text=temp_text, color=red, x=5, y=25)
@@ -65,26 +70,27 @@ def hpa_to_inHg(hPa):
 #  time.monotonic clock
 clock = 0
 #  units state
-us_units = False
+metric_units = False
 
 while True:
     #  non-blocking 2 second delay
     if (clock + 2) < time.monotonic():
         #  map servo range to barometric pressure range
-        servo_value = simpleio.map_range(bmp280.pressure, 970, 1050, 180, 0)
+        servo_value = simpleio.map_range(bmp280.pressure,
+                                         PRESSURE_LOW_LIM, PRESSURE_HIGH_LIM, 180, 0)
         #  set servo to pressure
         gauge.angle = servo_value
         #  print data for debugging
         print("\nTemperature: %0.1f C" % bmp280.temperature)
         print("Pressure: %0.1f hPa" % bmp280.pressure)
         print(servo_value)
-        #  if not US units...
-        if not us_units:
+        #  if metric units...
+        if metric_units:
             #  update temp & pressure text in celcius and hPa
             temp_data.text = "%0.1f ºC" % bmp280.temperature
             press_data.text = "%0.1f hPa" % bmp280.pressure
-        #  if US units...
-        if us_units:
+        #  if imperial units...
+        else:
             #  convert celcius to fahrenheit
             temp_fahrenheit = c_to_f(bmp280.temperature)
             #  convert hPa to inHg
@@ -94,9 +100,9 @@ def hpa_to_inHg(hPa):
             press_data.text = "%0.1f inHg" % pressure_inHg
         #  reset time.monotonic() clock
         clock = time.monotonic()
-    #  if a button is pressed, us_units is False, show imperial
+    #  if a button is pressed, metric_units is True, show metric
     if clue.button_a:
-        us_units = False
-    #  if b button is pressed, us_units is True, show US units
+        metric_units = True
+    #  if b button is pressed, metric_units is False, show imperial units
     if clue.button_b:
-        us_units = True
+        metric_units = False