I’m making a data logger using Arduino Uno Rev3 and an adafruit SD data logger shield.
When the user is finished with this logger they will then take out the SD card and put it into their PC.
I want to make sure that the user doesn’t modify the data on the SD card using their PC so I write 2 files with the Arduino that are named with the same number: “logger##” and “CheckS##”
Logger## contains the logger data and CheckS## contains the number of bytes in the Logger## file.
The user has to use a program I wrote in visual basic on the PC to look the logger files which compares the filesize of Logger## and the data in CheckS## to see if they match.
This works fine but of course the data can still be changed without my program detecting it as long as the number of bytes remain the same.
I’ve looked at CRC on arduino across google and I’ll be honest it’s going way over my head.
Does anyone know of a simple way to produce a checksum file of my logger data?