is there anyway to use my offline Android phone as a time se

[nutpantz]

I am using my pi primarily as a offline local ftp, calibre,mpd server,I am always connecting my android phone to it both with Wi-Fi and usb mtp.

Is there anyway I can use my offline android phone as a time server so my pi updates it's time when connected? My android phone is rooted.

[wayne.dolesman]

There are probably a couple ways.

The least accurate is to find an NTP server for android. This should not be terribly difficult. The phones clock drift would potentially cause issues if accuracy is your desire.

The more accurate way would be to use the phones GPS if it has one as a clock source. This can be done either by forwarding the NMEA sentences to the Pi or by finding an app that would set your android clock based on GPS data and then doing something like the NTP server previously mentioned.

It should not be terribly difficult to forward the NMEA data (or a pre-processed variant) through a network interface to the Pi.