Hi can someone please help me implement timestamp to my code?

So I have this code
Main code Arduino.ino (9.9 KB)
the code collects data that are being saved to SD card. This is successfully done. All I want is to implement is the timestamp in the saved file. Timestamp is being shown on the serial monitor as shown below (the circled one), but not in the saved file. Can someone please help?

Notice my file below does not have timestamp.

Thanks!

Write the value of millis( ) or micros( ) to the front of each line saved.

image

14 hours x 60 x60 + 03 minutes x 60 + 37 = long int_seconds

IF you must have 3 Decimal places, .805 x 1000 and save as a separate uint on the SD ... just remember to / 10^3 after reading SD.