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--- iothings:laboratoare:2022:lab7 [2023/11/20 21:35]
dan.tudose [Sparrow BLE Service]
+++ iothings:laboratoare:2022:lab7 [2025/09/28 17:46] (current)
dan.tudose [UUID]
@@ Line 72: / Line 72: @@
 In essence, the UUID serves the purpose of uniquely identifying information. For example, it can distinguish a specific service provided by a Bluetooth device.
+===== Advertise on BLE  =====
+Build the example below, which advertises the board on BLE. Install on your phone an app that scans nearby Bluetooth devices, such as [[https://play.google.com/store/apps/details?id=no.nordicsemi.android.mcp&hl=en&pli=1| nRF Connect]]. Check if your device is in the list.
+<code C main.cpp>
+#include <Arduino.h>
+#include <NimBLEDevice.h>
+static const char* DEVICE_NAME = "ESP32-C6 Demo";
+static NimBLEUUID SERVICE_UUID("6E400001-B5A3-F393-E0A9-E50E24DCCA9E");
+static NimBLEUUID CHAR_UUID   ("6E400002-B5A3-F393-E0A9-E50E24DCCA9E");
+NimBLEServer*         gServer = nullptr;
+NimBLEService*        gService = nullptr;
+NimBLECharacteristic* gChar = nullptr;
+void startBLE() {
+  NimBLEDevice::init(DEVICE_NAME);
+  gServer  = NimBLEDevice::createServer();
+  gService = gServer->createService(SERVICE_UUID);
+  gChar = gService->createCharacteristic(
+    CHAR_UUID,
+    NIMBLE_PROPERTY::READ
+  );
+  gChar->setValue("Hello from ESP32-C6!");
+  gService->start();
+  NimBLEAdvertising* adv = NimBLEDevice::getAdvertising();
+  // Advertise our service UUID
+  adv->addServiceUUID(SERVICE_UUID);
+  // (v2.x) Build advertising + scan-response payloads explicitly
+  NimBLEAdvertisementData advData;
+  advData.setFlags(0x06); // LE General Discoverable + BR/EDR Not Supported
+  NimBLEAdvertisementData scanData;
+  scanData.setName(DEVICE_NAME); // put the name in scan response
+  // you can also add manufacturer data here if you want:
+  // std::string mfg = "\x34\x12C6"; scanData.setManufacturerData(mfg);
+  adv->setAdvertisementData(advData);
+  adv->setScanResponseData(scanData);
+  // Appearance is still supported
+  adv->setAppearance(0x0200); // Generic Tag
+  NimBLEDevice::startAdvertising();
+}
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) { delay(10); }
+  startBLE();
+  Serial.println("Advertising as ESP32-C6 Demo. Open nRF Connect -> Scan.");
+}
+void loop() {
+  delay(1000);
+}
+</code>
+{{:iothings:laboratoare:lab1-ble-scanner.jpg?300|}}
 ===== Project Overview =====
@@ Line 113: / Line 179: @@
   - Create a BLE device (server) with a name of your choice (we’ll call it ESP32_BME680, but you can call it any other name).
   - Create an Environmental Sensing service (UUID: 0x181A).
-  - Add characteristics to that service:
+  - Add characteristics to that service: pressure (0x2A6D), temperature (0x2A6E) and humidity (0x246F)
-  * pressure: 0x2A6D
-  * temperature: 0x2A6E
-  * humidity: 0x246F
   - Add descriptors to the characteristics.
   - Start the BLE server.
@@ Line 123: / Line 186: @@
-Copy the following code to the Arduino IDE and upload it to your board.
+Copy the following code to the Arduino IDE, modify it and upload it to your board.
+<code C>
+#include <Arduino.h>
+#include <Wire.h>
+#include <Adafruit_BME680.h>
+#include <NimBLEDevice.h>
+/* ============================
+   User config
+   ============================ */
+static const char* DEVICE_NAME = "ESP32-C6 Env";   // shows in scan response
+#define I2C_SDA_PIN 21                             // adjust for your board
+#define I2C_SCL_PIN 22
+#define BME680_I2C_ADDR 0x77                      // try 0x76 if needed
+static const uint32_t MEAS_INTERVAL_MS = 2000;    // update period
+/* ============================
+   BLE UUIDs (Environmental Sensing)
+   ============================ */
+static NimBLEUUID ESS_UUID((uint16_t)0x181A);
+static NimBLEUUID TEMP_UUID((uint16_t)0x2A6E);  // Temperature
+static NimBLEUUID PRES_UUID((uint16_t)0x2A6D);  // Pressure
+static NimBLEUUID HUM_UUID ((uint16_t)0x2A6F);  // Humidity
+/* ============================
+   Globals
+   ============================ */
+NimBLEServer*         gServer   = nullptr;
+NimBLEService*        gService  = nullptr;
+NimBLECharacteristic* gTempChar = nullptr;
+NimBLECharacteristic* gPresChar = nullptr;
+NimBLECharacteristic* gHumChar  = nullptr;
+Adafruit_BME680 bme; // I2C
+uint32_t lastMeas = 0;
+/* ============================
+   Helpers: encode per SIG formats (little-endian)
+   ============================ */
+static void setTempCentiDeg(NimBLECharacteristic* ch, float celsius) {
+  // sint16, 0.01 °C
+  int32_t raw = lroundf(celsius * 100.0f);
+  if (raw >  32767) raw =  32767;
+  if (raw < -32768) raw = -32768;
+  int16_t v = (int16_t)raw;
+  uint8_t buf[2] = { (uint8_t)(v & 0xFF), (uint8_t)((v >> 8) & 0xFF) };
+  ch->setValue(buf, sizeof(buf));
+}
+static void setHumidityCentiPct(NimBLECharacteristic* ch, float rh) {
+  // uint16, 0.01 %RH (clip 0..100%)
+  if (rh < 0)   rh = 0;
+  if (rh > 100) rh = 100;
+  uint32_t raw = lroundf(rh * 100.0f);
+  if (raw > 0xFFFF) raw = 0xFFFF;
+  uint16_t v = (uint16_t)raw;
+  uint8_t buf[2] = { (uint8_t)(v & 0xFF), (uint8_t)((v >> 8) & 0xFF) };
+  ch->setValue(buf, sizeof(buf));
+}
+static void setPressureDeciPa(NimBLECharacteristic* ch, float pascals) {
+  // uint32, 0.1 Pa
+  if (pascals < 0) pascals = 0;
+  uint64_t raw = llroundf(pascals * 10.0f);
+  if (raw > 0xFFFFFFFFULL) raw = 0xFFFFFFFFULL;
+  uint32_t v = (uint32_t)raw;
+  uint8_t buf[4] = {
+    (uint8_t)(v & 0xFF),
+    (uint8_t)((v >> 8) & 0xFF),
+    (uint8_t)((v >> 16) & 0xFF),
+    (uint8_t)((v >> 24) & 0xFF)
+  };
+  ch->setValue(buf, sizeof(buf));
+}
+/* Add Characteristic Presentation Format (0x2904) */
+static void addCPF(NimBLECharacteristic* ch, uint8_t format, int8_t exponent, uint16_t unit) {
+  // 7 bytes: format, exponent, unit(LE), namespace(1=1), description(2=0)
+  uint8_t cpf[7] = {
+    format, (uint8_t)exponent,
+    (uint8_t)(unit & 0xFF), (uint8_t)((unit >> 8) & 0xFF),
+x01, 0x00, 0x00
+  };
+  ch->createDescriptor("2904")->setValue(cpf, sizeof(cpf));
+}
+/* ============================
+   BLE setup (keeps your adv/scan-response style)
+   ============================ */
+void startBLE() {
+  NimBLEDevice::init(DEVICE_NAME);
+  NimBLEDevice::setPower(ESP_PWR_LVL_P9);  // strong TX for gateways; lower if needed
+  NimBLEDevice::setSecurityAuth(false, false, true); // no bonding; SC on
+  gServer  = NimBLEDevice::createServer();
+  gService = gServer->createService(ESS_UUID);
+  // READ + NOTIFY for all three characteristics
+  auto props = (NIMBLE_PROPERTY::READ | NIMBLE_PROPERTY::NOTIFY);
+  gTempChar = gService->createCharacteristic(TEMP_UUID, props);
+  gPresChar = gService->createCharacteristic(PRES_UUID, props);
+  gHumChar  = gService->createCharacteristic(HUM_UUID,  props);
+  // Presentation formats
+  const uint8_t GATT_FORMAT_SINT16 = 0x0E;
+  const uint8_t GATT_FORMAT_UINT16 = 0x0D;
+  const uint8_t GATT_FORMAT_UINT32 = 0x10;
+  addCPF(gTempChar, GATT_FORMAT_SINT16, -2, 0x272F); // Celsius
+  addCPF(gPresChar, GATT_FORMAT_UINT32, -1, 0x2724); // Pascal, 0.1 exponent
+  addCPF(gHumChar,  GATT_FORMAT_UINT16, -2, 0x27AD); // Percentage
+  // Initialize with placeholder values so READ works before first measurement
+  setTempCentiDeg(gTempChar, 0.0f);
+  setPressureDeciPa(gPresChar, 101325.0f);
+  setHumidityCentiPct(gHumChar, 0.0f);
+  gService->start();
+  NimBLEAdvertising* adv = NimBLEDevice::getAdvertising();
+  // Advertise the standard Environmental Sensing Service UUID
+  adv->addServiceUUID(ESS_UUID);
+  // Your explicit adv + scan-response payloads
+  NimBLEAdvertisementData advData;
+  advData.setFlags(0x06); // LE General Discoverable + BR/EDR Not Supported
+  adv->setAdvertisementData(advData);
+  NimBLEAdvertisementData scanData;
+  scanData.setName(DEVICE_NAME);
+  adv->setScanResponseData(scanData);
+  // Appearance: Generic Thermometer (0x0300)
+  adv->setAppearance(0x0300);
+  NimBLEDevice::startAdvertising();
+  Serial.println("Advertising Environmental Sensing Service. Open nRF Connect -> Scan.");
+}
+/* ============================
+   BME680 setup
+   ============================ */
+bool startBME680() {
+  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);
+  if (!bme.begin(BME680_I2C_ADDR)) {
+    Serial.println("[BME680] Not found on 0x77, trying 0x76...");
+    if (!bme.begin(0x76)) {
+      Serial.println("[BME680] Sensor not found. Check wiring and power.");
+      return false;
+    }
+  }
+  // Oversampling & filter for stable readings
+  bme.setTemperatureOversampling(BME680_OS_8X);
+  bme.setHumidityOversampling(BME680_OS_2X);
+  bme.setPressureOversampling(BME680_OS_4X);
+  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
+  // Gas heater off (not needed for T/RH/P)
+  bme.setGasHeater(0, 0);
+  return true;
+}
+/* ============================
+   Measurement + GATT update
+   ============================ */
+void updateMeasurements() {
+  if (!bme.performReading()) {
+    Serial.println("[BME680] performReading() failed");
+    return;
+  }
+  float c = bme.temperature;  // °C
+  float h = bme.humidity;     // %RH
+  float p = bme.pressure;     // Pa
+  setTempCentiDeg(gTempChar, c);
+  setHumidityCentiPct(gHumChar, h);
+  setPressureDeciPa(gPresChar, p);
+  // Send notifications to any subscribed client
+  gTempChar->notify(true);
+  gHumChar->notify(true);
+  gPresChar->notify(true);
+  Serial.printf("[DATA] T=%.2f°C  RH=%.2f%%  P=%.1f Pa\n", c, h, p);
+}
+/* ============================
+   Arduino entry points
+   ============================ */
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) { delay(10); }
+  if (!startBME680()) {
+    // We still start BLE so you can see/connect even if sensor is missing
+  }
+  startBLE();
+}
+void loop() {
+  uint32_t now = millis();
+  if (now - lastMeas >= MEAS_INTERVAL_MS) {
+    lastMeas = now;
+    updateMeasurements();
+  }
+  delay(10);
+}
+</code>
+Upload the code to your board. After uploading, open the Serial Monitor, and restart the Sparrow by pressing the RST/EN button.
+You should get a data reading messages in the Serial Monitor.
+Then, go to your smartphone, open the nRF Connect app from Nordic, and start scanning for new devices. You should find a device called **ESP32-C6 Env**, this is the BLE server name you defined earlier.
+Connect to it. You’ll see that it displays the Environmental Sensing service with the temperature, humidity, and pressure characteristics. Click on the down arrows to activate the notifications.
+Then, click on the second icon (the one that looks like a " mark) at the left to change the format. You can change to unsigned int for all characteristics. You’ll start seeing the temperature, humidity, and pressure values being reported every 2 seconds.
+===== Web BLE Application =====
+Follow the tutorial [[https://randomnerdtutorials.com/esp32-web-bluetooth/| here]] to learn how to create a Web application that connects directly to your Sparrow ESP32 board. You can use the web app just like a normal phone application to send and receive information over BLE from your device.
+<note important>Web BLE is not currently supported by iOS phones </note>
+Build the application in the tutorial and deploy the web page in your GitHub account.
+=== Assignment ===
+<note> Modify the web page and the BLE app to display the BME680 sensor data (temperature, pressure and humidity). </note>