This project is about a datalogger, used to acquire data from sensors and store it in a micro SD card. It also can send the data wirelessly using ESP-NOW to another ESP32 microcontroller.

The main design requirements are:

• Portable, battery operated
• USB-C connection, to be modern and allow the user to download logged files directly from the device, without needing to touch the micro SD card.
• OLED screen, to check the measurement status.
• Very low quiescent current, to sleep in between measurements
• RTC, to keep accurate time for logging timestamps

With all of this in mind, here is the first revision schematic:

And here is the PCB Design:

For more info please watch my youtube video!