1  # SPDX-FileCopyrightText: 2022 Dan Halbert for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import asyncio
 6  import board
 7  import digitalio
 8  import keypad
 9  
10  
11  class Interval:
12      """Simple class to hold an interval value. Use .value to to read or write."""
13  
14      def __init__(self, initial_interval):
15          self.value = initial_interval
16  
17  
18  async def monitor_interval_buttons(pin_slower, pin_faster, interval):
19      """Monitor two buttons: one lengthens the interval, the other shortens it.
20      Change interval.value as appropriate.
21      """
22      # Assume buttons are active low.
23      with keypad.Keys(
24          (pin_slower, pin_faster), value_when_pressed=False, pull=True
25      ) as keys:
26          while True:
27              key_event = keys.events.get()
28              if key_event and key_event.pressed:
29                  if key_event.key_number == 0:
30                      # Lengthen the interval.
31                      interval.value += 0.1
32                  else:
33                      # Shorten the interval.
34                      interval.value = max(0.1, interval.value - 0.1)
35                  print("interval is now", interval.value)
36              # Let another task run.
37              await asyncio.sleep(0)
38  
39  
40  async def blink(pin, interval):
41      """Blink the given pin forever.
42      The blinking rate is controlled by the supplied Interval object.
43      """
44      with digitalio.DigitalInOut(pin) as led:
45          led.switch_to_output()
46          while True:
47              led.value = not led.value
48              await asyncio.sleep(interval.value)
49  
50  
51  async def main():
52      interval1 = Interval(0.5)
53      interval2 = Interval(1.0)
54  
55      led1_task = asyncio.create_task(blink(board.D1, interval1))
56      led2_task = asyncio.create_task(blink(board.D2, interval2))
57      interval1_task = asyncio.create_task(
58          monitor_interval_buttons(board.D3, board.D4, interval1)
59      )
60      interval2_task = asyncio.create_task(
61          monitor_interval_buttons(board.D5, board.D6, interval2)
62      )
63  
64      await asyncio.gather(led1_task, led2_task, interval1_task, interval2_task)
65  
66  
67  asyncio.run(main())