Set time when offline

[MatthewPageUK]

If we can't get a wifi connection need a way to set the time. A rotary dial on the back, use switches ...

[samveen]

An additional suggestion is to save the clock to disk so that there is a saved time value to reuse on reset, like the fake-hwclock on Raspbian:

"""
A boot.py that does time saving and restoring if a save is available.
"""
import ustruct
r=machine.RTC()

# Restore clock save or set sane default value if no save
try:
    with open("hwclock.save","rb") as fr: r.datetime(ustruct.unpack("<8I",fr.read()))
except OSError as e:
    r.datetime((2023, 1, 29, 6, 13, 55, 0, 0))

# function to save the RTC 
def rtSaverCallback(t):
    with open("hwclock.save","w") as fw: fw.write(ustruct.pack("<8I",*(r.datetime())))

# periodic firing of the function every 1000ms (longer or shorter as required)
rtsaver = machine.Timer(mode=machine.Timer.PERIODIC, period=1000, callback=rtSaverCallback)

[MatthewPageUK]

Thanks @samveen , that's a neat little idea.