A XIAO ESP32-S3 MicroPython example showcasing I2C sensor interfacing, WiFi connectivity, NTP and RTC time synchronization with time-zone support, and task scheduling. The development environment leverages Visual Studio Code with PyMakr extension and the Code Completion extension for MicroPython is recommended. The example's execution flow is as follows:
- Connects system to WiFi network
- Synchronizes system RTC with NTP host
- Disconnects system from WiFi network
- Poll's devices on I2C bus 0 once a minute
async def main() -> None:
"""Main subroutine"""
# Connect system to wifi network
await connect_wifi()
# Synchronize system clock with ntp time server
await synch_ntp_time()
# Disconnect system from wifi network
await disconnect_wifi()
# Create scheduled tasks
asyncio.create_task(scheduler.create_schedule(poll_i2c0_devices_task, "tsk1", hrs=None, mins=range(0, 60, 1))) # poll i2c device(s) every minute
while True:
try:
await asyncio.sleep(1)
except RuntimeError as error:
print('Runtime Error: ', error.args[0])
break
except OSError as e:
print('OS Error: ', e.args[0])
break
except KeyboardInterrupt:
print('Keyboard Interrupt')
break
The example interfaces the Bosch BMP280 and Sensirion SHT4X sensors over I2C. The I2C drivers for the Bosch BMP280 and Sensirion SHT4X sensors are random drivers that found online and seem to work fine for the purposes of this example. Task scheduling is handled by asyncio.create_task function and the scheduler module. WiFi connectivity and NTP time synchronization are handled by the net_if module, and time-zone is handled by the timezone module. The example's configuration is handled by the config module.
The master branch of the code base for the schedule module is located here: https://github.com/peterhinch/micropython-async/tree/197c2b5d72cc7633e4b3176eabdeef532ea09ffd/v3/as_drivers/sched. The readme files are amazing and the schedule readme is available here: https://github.com/peterhinch/micropython-async/blob/197c2b5d72cc7633e4b3176eabdeef532ea09ffd/v3/docs/SCHEDULE.md.
The timezone module is a lightweight implementation to support time-zone functionality in MicroPython. The system synchronizes its RTC with an NTP host once the system connects to a WiFi network and sets the system time to UTC by default. The time can be converted to local-time by specifying a time-zone information object as an argument for the localtime function.
# Instantiate timezone information object for Atlantic Canada with daylight saving start and end schedules.
tz_info = TimezoneInfo(TimeOffset(-4, 0), DSTSchedule(3, 9, 2, 0), DSTSchedule(11, 2, 2, 0), DSTAdjust(1, 0))
# Get local-time parts from system clock
(year, month, day, hrs, mins, secs, wday, yday) = timezone.localtime(tz_info)
The time_into_interval module is a lightweight implementation to support time-into-interval scheduling in MicroPython. The time-into-interval module synchronizes a MicroPython task with the system clock with user-defined time interval for temporal conditional scenarios. The shortest interval supported is 1-second and the longest interval supported is 28-days.
import asyncio
from scheduler import TimeIntoInterval, TimeIntoIntervalTypes
async def do_work_task(task_id: str) -> None:
"""Do Work Task.
A task to simulate work.
Args:
task_id (str): Task unique identifier.
"""
# Instantiate time-into-interval objects
tii_1_0min = TimeIntoInterval(TimeIntoIntervalTypes.TIME_INTO_INTERVAL_MIN, 1, 0) # 1-minute interval with no offset
tii_5_0min = TimeIntoInterval(TimeIntoIntervalTypes.TIME_INTO_INTERVAL_MIN, 5, 0) # 5-minute interval with no offset
tii_5_1min = TimeIntoInterval(TimeIntoIntervalTypes.TIME_INTO_INTERVAL_MIN, 5, 1) # 5-minute interval with 1-minute offset
# Loop forever
while True:
try:
# interval will elapse every 5-minutes (12:00:00, 12:05:00, 12:10:00, etc)
if tii_5_0min.interval_elapsed():
print(f"{task_id}: tii_5_0min.interval_elapsed: {format_localtime()}")
# interval will elapse every 5-minutes with a 1-minute offset (12:01:00, 12:06:00, 12:11:00, etc)
if tii_5_1min.interval_elapsed():
print(f"{task_id}: tii_5_1min.interval_elapsed: {format_localtime()}")
# interval will sleep for 1-minute (12:00:00, 12:01:00, 12:02:00, etc)
print(f"{task_id}: tii_1_0min.interval_sleep: {format_localtime()}")
await tii_1_0min.interval_sleep()
except RuntimeError as error:
print(f'{task_id}: Runtime Error: ', error.args[0])
break
except OSError as e:
print(f'{task_id}: OS Error: ', e.args[0])
break
except KeyboardInterrupt:
print(f'{task_id}: Keyboard Interrupt')
break
async def main() -> None:
# Create scheduled tasks
asyncio.create_task(do_work_task("tsk0"))
# Loop forever
while True:
try:
await asyncio.sleep(1)
except RuntimeError as error:
print('Runtime Error: ', error.args[0])
break
except OSError as e:
print('OS Error: ', e.args[0])
break
except KeyboardInterrupt:
print('Keyboard Interrupt')
break
"""Application entry point"""
if __name__ == '__main__':
try:
asyncio.run(main())
finally:
_ = asyncio.new_event_loop()
The above snippet example prints the following information over the serial port.
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:37
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:38
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:39
tsk0: tii_5_0min.interval_elapsed: 2025-02-22 10:40
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:40
tsk0: tii_5_1min.interval_elapsed: 2025-02-22 10:41
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:41
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:42
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:43
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:44
tsk0: tii_5_0min.interval_elapsed: 2025-02-22 10:45
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:45
tsk0: tii_5_1min.interval_elapsed: 2025-02-22 10:46
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:46
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:47
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:48
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:49
tsk0: tii_5_0min.interval_elapsed: 2025-02-22 10:50
tsk0: tii_1_0min.interval_sleep: 2025-02-22 10:50
This example is hosted on github and is located here: https://github.com/K0I05/XIAO-ESP32S3-PyMakr
Copyright (c) 2024 Eric Gionet (gionet.c.eric@gmail.com)