/* ESP32 start counter example with Preferences library This simple example demonstrate using Preferences library to store how many times was ESP32 module started. Preferences library is wrapper around Non-volatile storage on ESP32 processor. created for arduino-esp32 09 Feb 2017 by Martin Sloup (Arcao) */ #include Preferences preferences; void setup() { Serial.begin(115200); Serial.println(); // Open Preferences with my-app namespace. Each application module, library, etc. // has to use namespace name to prevent key name collisions. We will open storage in // RW-mode (second parameter has to be false). // Note: Namespace name is limited to 15 chars preferences.begin("my-app", false); // Remove all preferences under opened namespace //preferences.clear(); // Or remove the counter key only //preferences.remove("counter"); // Get a counter value, if key is not exist return default value 0 // Note: Key name is limited to 15 chars too unsigned int counter = preferences.getUInt("counter", 0); // Increase counter counter++; // Print counter to a Serial Serial.printf("Current counter value: %u\n", counter); // Store counter to the Preferences preferences.putUInt("counter", counter); // Close the Preferences preferences.end(); // Wait 10 seconds Serial.println("Restarting in 10 seconds..."); delay(10000); // Restart ESP ESP.restart(); } void loop() {}