Updates to API and added arduino code for the XIAO-ESP32C6

soilProbeESP32C6/.theia/launch.json

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+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  "version": "0.2.0",
+  "configurations": [
+  
+  ]
+}

soilProbeESP32C6/soilProbeESP32C6.ino

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+#include <Arduino.h>
+#include <BLEDevice.h>
+#include <BLEServer.h>
+#include <BLEUtils.h>
+#include <BLE2902.h>
+#include <EEPROM.h>
+#include <esp_sleep.h>
+
+// ======== BLE UUIDs ========
+#define SERVICE_UUID        "12345678-1234-1234-1234-123456789abc"
+#define CHARACTERISTIC_UUID "abcd1234-5678-1234-5678-abcdef123456"
+
+// ======== Hardware & ADC ========
+#define MOISTURE_PIN A0
+#define LED_PIN      2 // Example LED pin (built-in LED on many ESP32 boards)
+#define BUTTON_PIN   D4 // GPIO 4 for calibration button (recommended over GPIO 0)
+
+// ======== Constants ========
+const int DRY_VALUE_DEFAULT = 500;
+const int WET_VALUE_DEFAULT = 200;
+const int ADC_RESOLUTION = 10;  // 10-bit ADC (0–1023)
+
+// ======== Reading & Averaging ========
+const int NUM_SAMPLES = 5;        // Number of samples to average
+const int SAMPLE_DELAY_MS = 50;   // Delay between each sample (ms)
+
+// ======== Connection Timeout Settings ========
+const unsigned long CONNECTION_TIMEOUT_MS = 120000; // 2 minutes to establish connection
+unsigned long connectionStartTime = 0;
+bool connectionTimerStarted = false;
+
+// ======== Sleep Settings ========
+const uint64_t DEEP_SLEEP_DURATION_US = 60ULL * 60ULL * 1000000ULL; // 1 hour in microseconds
+
+// ======== Calibration Variables ========
+int dryValue = DRY_VALUE_DEFAULT; // Initialize with default dry value
+int wetValue = WET_VALUE_DEFAULT; // Initialize with default wet value
+
+// ======== Device Configuration ========
+const char* deviceName = "003-SoilSensor"; // Default device name
+
+// ======== EEPROM Addresses ========
+const int EEPROM_SIZE = 512;
+const int EEPROM_DRY_ADDRESS = 0;  // Bytes 0-3
+const int EEPROM_WET_ADDRESS = 4;  // Bytes 4-7
+
+// ======== BLE Objects ========
+BLEServer* pServer = nullptr;
+BLECharacteristic* pCharacteristic = nullptr;
+
+// ======== Device State Flags ========
+bool isConnected = false;
+bool dataSent = false;
+
+// ======== Calibration Variables ========
+enum DeviceState {
+  STATE_NORMAL,
+  STATE_CALIBRATE_NOT_IN_SOIL,
+  STATE_CALIBRATE_IN_SOIL
+};
+
+DeviceState currentState = STATE_NORMAL;
+int calibrationCount = 0;
+
+// ======== Button Handling ========
+const unsigned long DEBOUNCE_DELAY = 50; // 50ms debounce delay
+bool lastButtonState = HIGH;              // Assuming pull-up resistor
+bool buttonPressed = false;
+unsigned long lastDebounceTime = 0;
+
+// ======== LED Blinking Parameters ========
+unsigned long previousBlinkTime = 0;
+const unsigned long BLINK_ON_DURATION = 200;  // 200ms ON
+const unsigned long BLINK_OFF_DURATION = 100; // 100ms OFF
+bool ledState = false;
+
+// ======== Function Prototypes ========
+int readSoilMoisture();
+int getAveragedMoisture(int numSamples);
+void enterDeepSleep();
+void handleCalibrationButtonPress();
+void readCalibrationValues();
+void writeCalibrationValues(int dry, int wet);
+void checkButtonPress();
+void updateLED();
+
+// ======== Custom Server Callbacks ========
+class MyServerCallbacks : public BLEServerCallbacks {
+  void onConnect(BLEServer* pServer) override {
+    Serial.println("Client connected.");
+    isConnected = true;
+
+    // Turn on LED to indicate active state
+    digitalWrite(LED_PIN, HIGH);
+
+    // Stop connection timeout timer
+    connectionTimerStarted = false;
+    connectionStartTime = 0;
+  }
+
+  void onDisconnect(BLEServer* pServer) override {
+    Serial.println("Client disconnected.");
+    isConnected = false;
+    dataSent = false;
+
+    // Restart advertising to allow new connections
+    pServer->startAdvertising();
+
+    // Restart connection timeout timer
+    connectionTimerStarted = true;
+    connectionStartTime = millis();
+
+    // Turn off LED to indicate sleep state
+    digitalWrite(LED_PIN, LOW);
+  }
+};
+
+// ======== Sensor Reading Functions ========
+/**
+ * Perform a single soil moisture reading (0–100%).
+ */
+int readSoilMoisture() {
+  int rawValue = analogRead(MOISTURE_PIN);
+  int percent  = map(rawValue, dryValue, wetValue, 0, 100);
+  return constrain(percent, 0, 100);
+}
+
+/**
+ * Gathers multiple samples, applies a small delay between each,
+ * averages them, and returns the final moisture value.
+ */
+int getAveragedMoisture(int numSamples) {
+  long sum = 0;
+
+  for (int i = 0; i < numSamples; i++) {
+    sum += readSoilMoisture();
+    delay(SAMPLE_DELAY_MS);  // Small delay between samples
+  }
+
+  int avg = (int)(sum / numSamples);
+  return avg;
+}
+
+/**
+ * Enter deep sleep mode for the defined duration.
+ */
+void enterDeepSleep() {
+  Serial.println("Entering deep sleep for 1 hour...");
+
+  // Turn off LED to indicate sleep state
+  digitalWrite(LED_PIN, LOW);
+  
+  // Disable BLE before sleeping
+  BLEDevice::deinit(true);
+
+  // Configure deep sleep wake-up time
+  esp_sleep_enable_timer_wakeup(DEEP_SLEEP_DURATION_US);
+
+  // Enter deep sleep
+  esp_deep_sleep_start();
+}
+
+/**
+ * Handle calibration button presses to manage calibration steps.
+ */
+void handleCalibrationButtonPress() {
+  calibrationCount++;
+
+  switch (calibrationCount) {
+    case 1:
+      // Calibration Step 1: Record Dry Value
+      Serial.println("Calibration Step 1: Place device in dry soil and press button.");
+      currentState = STATE_CALIBRATE_NOT_IN_SOIL;
+      break;
+
+    case 2:
+      // Calibration Step 2: Record Wet Value
+      Serial.println("Calibration Step 2: Place device in wet soil and press button.");
+      currentState = STATE_CALIBRATE_IN_SOIL;
+      break;
+
+    case 3:
+      // Calibration Complete
+      Serial.println("Calibration Complete. Returning to normal operation.");
+      currentState = STATE_NORMAL;
+      calibrationCount = 0; // Reset for next calibration
+      break;
+
+    default:
+      // Reset Calibration
+      Serial.println("Calibration Reset. Returning to normal operation.");
+      currentState = STATE_NORMAL;
+      calibrationCount = 0;
+      break;
+  }
+
+  updateLED();
+}
+
+/**
+ * Read calibration values from EEPROM.
+ */
+void readCalibrationValues() {
+  EEPROM.get(EEPROM_DRY_ADDRESS, dryValue);
+  EEPROM.get(EEPROM_WET_ADDRESS, wetValue);
+  
+  // Validate calibration values
+  if (dryValue == 0xFFFFFFFF || wetValue == 0xFFFFFFFF) {
+    dryValue = DRY_VALUE_DEFAULT;
+    wetValue = WET_VALUE_DEFAULT;
+  }
+}
+
+/**
+ * Write calibration values to EEPROM.
+ */
+void writeCalibrationValues(int dry, int wet) {
+  EEPROM.put(EEPROM_DRY_ADDRESS, dry);
+  EEPROM.put(EEPROM_WET_ADDRESS, wet);
+  EEPROM.commit();
+}
+
+/**
+ * Check for button presses with debouncing.
+ */
+void checkButtonPress() {
+  bool reading = digitalRead(BUTTON_PIN);
+
+  if (reading != lastButtonState) {
+    lastDebounceTime = millis();
+  }
+
+  if ((millis() - lastDebounceTime) > DEBOUNCE_DELAY) {
+    if (reading == LOW && lastButtonState == HIGH) {
+      buttonPressed = true;
+    }
+  }
+
+  lastButtonState = reading;
+}
+
+/**
+ * Update LED based on the current state.
+ */
+void updateLED() {
+  // Reset LED parameters
+  previousBlinkTime = millis();
+  ledState = false;
+
+  switch (currentState) {
+    case STATE_NORMAL:
+      // LED is handled by BLE connection callbacks
+      digitalWrite(LED_PIN, LOW); // Ensure LED is off in normal mode
+      break;
+
+    case STATE_CALIBRATE_NOT_IN_SOIL:
+      // Solid LED to indicate calibration for dry soil
+      digitalWrite(LED_PIN, HIGH);
+      break;
+
+    case STATE_CALIBRATE_IN_SOIL:
+      // Start blinking in 2:1 ratio for wet soil calibration
+      digitalWrite(LED_PIN, HIGH); // Start with LED ON
+      ledState = true;
+      break;
+  }
+}
+
+/**
+ * Initialize EEPROM and read calibration values.
+ */
+void initializeEEPROM() {
+  if (!EEPROM.begin(EEPROM_SIZE)) {
+    Serial.println("Failed to initialize EEPROM");
+    // Handle EEPROM initialization failure if necessary
+  }
+  readCalibrationValues();
+}
+
+/**
+ * Update mapping based on calibrated dry and wet values.
+ */
+int mapMoisture(int rawValue) {
+  int percent = map(rawValue, dryValue, wetValue, 0, 100);
+  return constrain(percent, 0, 100);
+}
+
+// ======== Setup Function ========
+void setup() {
+  // Initialize Serial
+  Serial.begin(115200);
+  delay(1000); // Allow time for serial to initialize
+
+  // Initialize LED pin
+  pinMode(LED_PIN, OUTPUT);
+  digitalWrite(LED_PIN, LOW); // LED off initially
+
+  // Initialize Button pin
+  pinMode(BUTTON_PIN, INPUT_PULLUP); // Use INPUT_PULLUP if using internal resistor
+  // If using external resistor, use INPUT instead:
+  // pinMode(BUTTON_PIN, INPUT);
+
+  // Initialize EEPROM
+  initializeEEPROM();
+  Serial.printf("Calibrated Dry Value: %d\n", dryValue);
+  Serial.printf("Calibrated Wet Value: %d\n", wetValue);
+
+  // Initialize BLE with deviceName variable
+  BLEDevice::init(deviceName); // Initialize BLE with the variable device name
+  pServer = BLEDevice::createServer();
+  pServer->setCallbacks(new MyServerCallbacks());
+
+  // Create BLE service
+  BLEService* pService = pServer->createService(SERVICE_UUID);
+
+  // Create BLE characteristic
+  pCharacteristic = pService->createCharacteristic(
+    CHARACTERISTIC_UUID,
+    BLECharacteristic::PROPERTY_READ | BLECharacteristic::PROPERTY_NOTIFY
+  );
+
+  // Add descriptor for notifications
+  pCharacteristic->addDescriptor(new BLE2902());
+
+  // Start the service
+  pService->start();
+
+  // Start advertising
+  pServer->getAdvertising()->addServiceUUID(SERVICE_UUID);
+  pServer->getAdvertising()->setScanResponse(true);
+  pServer->getAdvertising()->start();
+
+  Serial.println("BLE server is running...");
+
+  // Start connection timeout timer
+  connectionTimerStarted = true;
+  connectionStartTime = millis();
+
+  // Initialize state and LED
+  currentState = STATE_NORMAL;
+  calibrationCount = 0;
+  updateLED();
+}
+
+// ======== Loop Function ========
+void loop() {
+  // Check for button presses
+  checkButtonPress();
+
+  if (buttonPressed) {
+    buttonPressed = false;
+    if (currentState != STATE_NORMAL) {
+      // Handle calibration step
+      handleCalibrationButtonPress();
+    } else {
+      // Initiate calibration
+      Serial.println("Button pressed. Initiating calibration mode.");
+      currentState = STATE_CALIBRATE_NOT_IN_SOIL;
+      calibrationCount = 1;
+      updateLED();
+    }
+  }
+
+  unsigned long currentTime = millis();
+
+  // ======== Connection Timeout Logic ========
+  if (connectionTimerStarted) {
+    if (currentTime - connectionStartTime >= CONNECTION_TIMEOUT_MS) {
+      Serial.println("No connection within 2 minutes. Entering deep sleep.");
+      enterDeepSleep();
+    }
+  }
+
+  // ======== BLE Connected Logic ========
+  if (isConnected && !dataSent && currentState == STATE_NORMAL) {
+    // Take sensor readings
+    int rawMoisture = analogRead(MOISTURE_PIN);
+    int moistureAvg = mapMoisture(rawMoisture);
+    Serial.printf("Averaged Soil Moisture: %d%%\n", moistureAvg);
+
+    // Update the characteristic and notify the client
+    pCharacteristic->setValue(moistureAvg);
+    pCharacteristic->notify();
+
+    dataSent = true;
+
+    // Immediately enter deep sleep after sending data
+    enterDeepSleep();
+  }
+
+  // ======== LED Update ========
+  updateLED();
+
+  // ======== LED Blinking Logic ========
+  if (currentState == STATE_CALIBRATE_IN_SOIL) {
+    if (millis() - previousBlinkTime >= (ledState ? BLINK_ON_DURATION : BLINK_OFF_DURATION)) {
+      ledState = !ledState;
+      digitalWrite(LED_PIN, ledState ? HIGH : LOW);
+      previousBlinkTime = millis();
+    }
+  }
+
+  // Short delay to prevent watchdog resets
+  delay(100);
+}