initialize

CPB_heart_rate_display/code.py

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+"""
+Circuit Playground Bluefruit BLE Heart Rate Display
+Read heart rate data from a heart rate peripheral using
+the standard BLE heart rate service.
+The heart rate monitor connects to the CPB via BLE.
+LEDs on CPB blink to the heart rate of the user.
+"""
+
+import time
+import board
+import neopixel
+import adafruit_ble
+from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
+from adafruit_ble.services.standard.device_info import DeviceInfoService
+from adafruit_ble_heart_rate import HeartRateService
+from digitalio import DigitalInOut, Direction
+
+#on-board status LED setup
+red_led = DigitalInOut(board.D13)
+red_led.direction = Direction.OUTPUT
+red_led.value = True
+
+#NeoPixel code
+pixels = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness=0.2, auto_write=False)
+RED = (255, 0, 0)
+LIGHTRED = (20, 0, 0)
+
+def color_chase(color, wait):
+    for i in range(10):
+        pixels[i] = color
+        time.sleep(wait)
+        pixels.show()
+    time.sleep(0.5)
+
+# animation to show initialization of program
+color_chase(RED, 0.1)  # Increase the number to slow down the color chase
+
+#starting bpm value
+bpm = 60
+
+# PyLint can't find BLERadio for some reason so special case it here.
+ble = adafruit_ble.BLERadio()    # pylint: disable=no-member
+
+hr_connection = None
+
+# Start with a fresh connection.
+if ble.connected:
+    time.sleep(1)
+
+    for connection in ble.connections:
+        if HeartRateService in connection:
+            connection.disconnect()
+        break
+
+while True:
+    print("Scanning...")
+    red_led.value = True
+    time.sleep(1)
+
+    for adv in ble.start_scan(ProvideServicesAdvertisement, timeout=5):
+        if HeartRateService in adv.services:
+            print("found a HeartRateService advertisement")
+            hr_connection = ble.connect(adv)
+            time.sleep(2)
+            print("Connected")
+            red_led.value = False
+            break
+
+    # Stop scanning whether or not we are connected.
+    ble.stop_scan()
+    print("Stopped scan")
+    red_led.value = False
+    time.sleep(0.5)
+
+    if hr_connection and hr_connection.connected:
+        print("Fetch connection")
+        if DeviceInfoService in hr_connection:
+            dis = hr_connection[DeviceInfoService]
+            try:
+                manufacturer = dis.manufacturer
+            except AttributeError:
+                manufacturer = "(Manufacturer Not specified)"
+            try:
+                model_number = dis.model_number
+            except AttributeError:
+                model_number = "(Model number not specified)"
+            print("Device:", manufacturer, model_number)
+        else:
+            print("No device information")
+        hr_service = hr_connection[HeartRateService]
+        print("Location:", hr_service.location)
+
+        while hr_connection.connected:
+            values = hr_service.measurement_values
+            print(values)  # returns the full heart_rate data set
+            if values:
+                bpm = (values.heart_rate)
+                if values.heart_rate == 0:
+                    print("-")
+                else:
+                    time.sleep(0.1)
+                    print(bpm)
+            if bpm != 0: # prevent from divide by zero
+                #find interval time between beats
+                bps = bpm / 60
+                period = 1 / bps
+                time_on = 0.375 * period
+                time_off = period - time_on
+
+                # Blink leds at the given BPM
+                pixels.fill(RED)
+                pixels.show()
+                # Increase or decrease to change the speed of the solid color change.
+                time.sleep(time_on)
+                pixels.fill(LIGHTRED)
+                pixels.show()
+                time.sleep(time_off)