Download information from ATmega328p through USB

[noiasca]

@evansg124

And now the idea that I had is the following. One of the boards that I have is a microbalance that gets temperature, humidity and frequency values of the the xtals and displays all the information on a Nextion screen and stores them in an SD in .CSV format so I can later look at it in excel. However, now I would like to know if it is possible to build a GUI that can pull the data from my board via USB for example, so I don't have to extract the micro SD card every time I want to do that.

Yes, it is for sure possible to read data from SD-Card and stream it to the Serial Monitor.
Just keep in mind, that a Arduino Uno will reboot, if you connect it to serial. But as you have your data on SD, that should not be an issue.

By the way, if you think about "Downloading" Data from SD via Ethernet using an Ethernet/SD Shield instead of Serial connection, I have a short example here: https://werner.rothschopf.net/microcontroller/202108_arduino_webserver_ntp_sd_en.htm