SeedStudio-ESP32-C3-WifitoSDcard

SeedStudio-ESP32-C3-WifitoSDcard

This code is for an Seed Studio ESP32-C3 board project that scans for nearby Wi-Fi networks, retrieves information about them, and saves that information to an SD card in a CSV (Comma-Separated Values) file format. Let's go through each function and its purpose:

1. listDir(const char *dirname, uint8_t levels):

   • This function is declared but not defined in the provided code snippet. It appears to be part of a larger program or library but is not implemented here.

2. createTestFile():

   • This function creates a test file named "test.txt" on the SD card if it doesn't already exist.
   • It writes the text "Test SD card." to the file.
   • It prints a message to the serial monitor to indicate whether the file creation was successful or if there was an error.

3. setup():

   • This is the setup function, which is executed once when the Arduino is powered on or reset.
   • It initializes the serial communication for debugging purposes.
   • It attempts to initialize the SD card using the specified chip select pin (chipSelect). If successful, it prints a message indicating that the card is mounted.
   • It then lists the files in the root directory of the SD card using the undefined listDir function.
   • It calls the createTestFile() function to create a test file on the SD card.
   • Finally, it sets up the Arduino as a Wi-Fi station (client) and disconnects from any previously connected access point.

4. generateNewFilename():

   • This function generates a new filename for the CSV files that will store the Wi-Fi scan results.
   • It uses a base filename (baseFilename), appends a numerical file number (incremented each time the function is called), and adds a file extension (fileExtension).
   • The generated filename is returned as a string.

5. saveScanResultsToSDWithMAC(int scanCount):

   • This function saves the scan results of nearby Wi-Fi networks to an SD card file in CSV format.
   • It generates a new filename using the generateNewFilename() function.
   • It opens the file for writing and writes a header line with column names: "SSID, RSSI, Channel, Encryption, MAC."
   • It then iterates through the scan results, collecting information about each network (SSID, RSSI, channel, encryption type, and MAC address), and writes this information to the file as a CSV entry for each network.
   • After all the information is written, the file is closed.
   • A message indicating the successful saving of the scan results or an error message is printed to the serial monitor.

6. loop():

   • This is the main loop of the Arduino program, which runs repeatedly after the setup() function has executed.
   • It starts by printing "Scan start" to the serial monitor.
   • It scans for nearby Wi-Fi networks using WiFi.scanNetworks() and stores the number of networks found in n.
   • If no networks are found (n == 0), it prints "No networks found" to the serial monitor.
   • If networks are found, it iterates through the scan results, printing information about each network to the serial monitor in a formatted table.
   • It then calls the saveScanResultsToSDWithMAC(n) function to save the scan results to the SD card.
   • After saving the results, it deletes the scan results to free up memory and waits for a brief period before scanning again (5 seconds in this case).

Please note that the listDir function is declared but not implemented in the provided code snippet. To understand its functionality, you would need to look at the rest of the code that includes its implementation.