Set RTC from PC datetime (no network connection)

  • I would like to set the RTC of a WiPy with the exact datetime on the computer it is connected to via USB. I know that rtc.ntp_sync() can be used to sync the RTC with a network but I will need to sync these devices in remote locations that don't have access to a wifi network (also no LoRa or LTE connection). Is there a way to query the datetime of the computer and set the WiPy RTC to that date time?

  • Global Moderator

    @alexpul Neat work around, Good job!

  • Here is a small script I wrote that sets the WiPy RTC from the PC datetime. The script is run through python on the computer and the device is connected via USB. (Note that it requires serial connection of UART0 to have a duplicated terminal - see uos.dupterm() in the pycom documentation for more details).

    import serial
    from datetime import datetime
    ## Get PC datetime
    pc_RTC =				#get datetime of PC
    pc_datetime = pc_RTC.timetuple()	#convert datetime to tuple
    datetime_tuple = pc_datetime[0:6] 	#get datetime entries in same format as WiPy RTC
    ## Set datetime over serial connection 
    ser = serial.Serial(port='COM1', baudrate=9600, writeTimeout=1, timeout=1) # initialize serial connection
    input = 'from machine import RTC\r\nintRTC = RTC()\r\nintRTC.init(' + str(datetime_tuple) + ')\r\n' #WiPy commands to set RTC datetime
    ser.write(input) #send commands over USB serial connection

  • Global Moderator

    Given you can init the RTC with anytime you want:

    # for 2nd of February 2017 at 10:30am (TZ 0)
    rtc.init((2017, 2, 28, 10, 30, 0, 0, 0))

    I see no reasons you could not use the serial connection between a pc and the WiPy to sync time.

    That said you'd need to write an application to run on said PC to write its current time out over serial.
    And adjust your wipy code to read that time out of the serial and init the RTC clock.


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