Micropython - Adjusting for Daylight Savings and Updating the RTC of the SBC
So you are using 'ntptime.settime()' in Micropython to update the time in your script for whatever purpose you are using it for and you want to adjust for Daylight Savings. Micropython doesn't support in the ntptime module handling that automatically, so here is a short work around to adjust the time appropriately for your RTC.
Here's my time sync function that I use, it's pretty self explanatory as far as the code. Adjust it to your needs as you see fit.
# Connect to wifi and synchronize the RTC time from NTP def sync_time(): global cset, year, month, day, wd, hour, minute, second # Reset the RTC time, reset if not try: rtc.datetime((2023, 1, 1, 0, 0, 0, 0, 0)) # Reset to a known good time year, month, day, wd, hour, minute, second, _ = rtc.datetime() if not all(isinstance(x, int) for x in ): raise ValueError("Invalid time values in RTC") except (ValueError, OSError) as e: print(f"RTC reset required: {e}") rtc.datetime((2023, 1, 1, 0, 0, 0, 0, 0)) # Reset to a known good time year, month, day, wd, hour, minute, second, _ = rtc.datetime() if not net: return if net: try: ntptime.settime() print("Time set") cset = True except OSError as e: print(f'Exception setting time {e}') cset = False # Get the current time in UTC y, mnth, d, h, m, s, wkd, yearday = time.localtime() # Create a time tuple for January 1st of the current year (standard time) jan_1st = (year, 1, 1, 0, 0, 0, 0, 0) # Create a time tuple for July 1st of the current year (daylight saving time, if applicable) jul_1st = (year, 7, 1, 0, 0, 0, 0, 0) # Determine if daylight saving time (CDT) is in effect is_dst = time.localtime(time.mktime(jul_1st)) != time.localtime(time.mktime(jan_1st)) # Set the appropriate UTC offset utc_offset = -5 # CST if is_dst: utc_offset = -6 # CDT hour = (h + utc_offset) % 24 # If hour became 0 after modulo, it means we crossed into the previous day if hour == 0 and h + utc_offset < 0: # Decrement the day, handling month/year transitions if necessary d -= 1 if d == 0: mnth -= 1 if mnth == 0: y -= 1 mnth = 12 # Adjust for the number of days in the previous month d = 31 # Start with the assumption of 31 days if mnth in : d = 30 elif mnth == 2: d = 29 if (y % 4 == 0 and (y % 100 != 0 or y % 400 == 0)) else 28 # Check all values before setting RTC if not (1
