feat: add ble server-client code

ble_server/ble_server.ino

@@ -0,0 +1,138 @@
+#include <BLEDevice.h>
+#include <BLEServer.h>
+#include <BLEUtils.h>
+#include <BLE2902.h>
+#include <Wire.h>
+#include "MPU6050.h"
+
+//BLE server name
+#define bleServerName "ESP32"
+
+int16_t ax, ay, az;
+int16_t gx, gy, gz;
+
+bool deviceConnected = false;
+
+// See the following for generating UUIDs:
+// https://www.uuidgenerator.net/
+#define SERVICE_UUID "91bad492-b950-4226-aa2b-4ede9fa42f59"
+
+MPU6050 accelgyro;
+BLEServer *pServer;
+BLECharacteristic bmeTemperatureCelsiusCharacteristics("cba1d466-344c-4be3-ab3f-189f80dd7518", BLECharacteristic::PROPERTY_NOTIFY);
+BLEDescriptor bmeTemperatureCelsiusDescriptor(BLEUUID((uint16_t)0x2902));
+
+//Setup callbacks onConnect and onDisconnect
+class MyServerCallbacks: public BLEServerCallbacks {
+  void onConnect(BLEServer* pServer) {
+    deviceConnected = true;
+    Serial.println("Device Connected");
+  };
+  void onDisconnect(BLEServer* pServer) {
+    deviceConnected = false;
+    Serial.println("Device Disconnected");
+  }
+};
+
+
+void setup() {
+  // Start serial communication 
+  Serial.begin(115200);
+  
+  // setup software i2c
+  Wire.begin();
+  
+  // initialize device
+  Serial.println("Initializing I2C devices...");
+  accelgyro.initialize();
+
+  // verify connection
+  Serial.println("Testing device connections...");
+  Serial.println(accelgyro.testConnection() ? "MPU6050 connection successful" : "MPU6050 connection failed");
+
+  // Create the BLE Device
+  BLEDevice::init(bleServerName);
+
+  // Create the BLE Server
+  pServer = BLEDevice::createServer();
+  pServer->setCallbacks(new MyServerCallbacks());
+
+  // Create the BLE Service
+  BLEService *bmeService = pServer->createService(SERVICE_UUID);
+
+  // Create BLE Characteristics and Create a BLE Descriptor
+  bmeService->addCharacteristic(&bmeTemperatureCelsiusCharacteristics);
+  bmeTemperatureCelsiusDescriptor.setValue("BME temperature Celsius");
+  bmeTemperatureCelsiusCharacteristics.addDescriptor(&bmeTemperatureCelsiusDescriptor);
+  
+  // Start the service
+  bmeService->start();
+
+  // Start advertising
+  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
+  pAdvertising->addServiceUUID(SERVICE_UUID);
+  pServer->getAdvertising()->start();
+  Serial.println("Waiting a client connection to notify...");
+}
+
+int idx = 0;
+
+void serialize_int16_t(uint8_t* buffer, int16_t* values, size_t count) {
+    for (size_t i = 0; i < count; ++i) {
+        buffer[i * 2] = (uint8_t)(values[i] & 0xFF);
+        buffer[i * 2 + 1] = (uint8_t)((values[i] >> 8) & 0xFF);
+    }
+}
+
+
+void loop() {
+
+  idx++;
+
+  if (deviceConnected) {
+
+    // read raw accel/gyro measurements from device
+    accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz); 
+
+    int16_t values[] = {ax, ay, az, gx, gy, gz};
+    size_t count = sizeof(values) / sizeof(values[0]);
+
+    // Serialize
+    uint8_t serializedBuffer[count * 2];
+    serialize_int16_t(serializedBuffer, values, count);
+
+    // Set characteristic value and notify connected client
+    bmeTemperatureCelsiusCharacteristics.setValue(serializedBuffer, count * 2);
+    bmeTemperatureCelsiusCharacteristics.notify();
+    if (idx % 20 == 0 && false) {
+      // display tab-separated accel/gyro x/y/z values
+      Serial.print("a/g:\t");
+      Serial.print(ax);
+      Serial.print("\t");
+      Serial.print(ay);
+      Serial.print("\t");
+      Serial.print(az);
+      Serial.print("\t");
+      Serial.print(gx);
+      Serial.print("\t");
+      Serial.print(gy);
+      Serial.print("\t");
+      Serial.println(gz);
+    }
+
+  }
+
+    // Check for a reset command from serial
+  if (Serial.available() > 0) {
+    char command = Serial.read();
+
+    // Check if the received command is 'R'
+    if (command == 'R' || command == 'r') {
+      Serial.println("Resetting...");
+      delay(1000); // Optional delay for visibility in the Serial Monitor
+      ESP.restart(); // This function resets the ESP32
+    }
+  }
+
+  delay(20);
+}