ble_uart.cpp

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

BLEServer *pServer = NULL;
BLECharacteristic * pTxCharacteristic;
bool deviceConnected = false;
bool oldDeviceConnected = false;
float m[9] = {0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0};
char glove_measurement_buffer[512];
uint8_t data[13] = "Hola soy jaz";
int counter = 0;
int num = 0;
int data_size;

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID           "7056f14b-02df-4dd8-86fd-0261c7b15c86" // UART service UUID
#define CHARACTERISTIC_UUID_TX "47e62e53-e278-494d-a3f8-ac00973ae0af"


class MyServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
      deviceConnected = true;
      Serial.println("device connected");
    };

    void onDisconnect(BLEServer* pServer) {
      deviceConnected = false;
      Serial.println("device disconected");
    }
};

class MyCallbacks: public BLECharacteristicCallbacks {
    void onWrite(BLECharacteristic *pCharacteristic) {
      std::string rxValue = pCharacteristic->getValue();

      if (rxValue.length() > 0) {
        Serial.println("*********");
        Serial.print("Received Value: ");
        for (int i = 0; i < rxValue.length(); i++)
          Serial.print(rxValue[i]);

        Serial.println();
        Serial.println("*********");
      }
    }
};


void setup() {
  Serial.begin(115200);

  // Create the BLE Device
  BLEDevice::init("RightHandSmartGlove");

  // Create the BLE Server
  pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  Serial.print("service id ");Serial.println(SERVICE_UUID);

  // Create the BLE Service
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create a BLE Characteristic
  pTxCharacteristic = pService->createCharacteristic(
										CHARACTERISTIC_UUID_TX,
										BLECharacteristic::PROPERTY_NOTIFY);
                 
  Serial.print("characteristic id ");Serial.println(CHARACTERISTIC_UUID_TX);             
                      
  pTxCharacteristic->addDescriptor(new BLE2902());

  // Start the service
  pService->start();

  // Start advertising
  pServer->getAdvertising()->start();
  Serial.println("Waiting a client connection to notify...");
}



void loop() {
    if (deviceConnected) {
        int size_written =  sprintf(glove_measurement_buffer, "%d\nP%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f\nR%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f\nM%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f\nI%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f\nT%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f;",
        counter,
        m[0], m[1], m[2], m[3], m[3], m[5], m[6], m[7], m[8],
        m[0], m[1], m[2], m[3], m[3], m[5], m[6], m[7], m[8],
        m[0], m[1], m[2], m[3], m[3], m[5], m[6], m[7], m[8],
        m[0], m[1], m[2], m[3], m[3], m[5], m[6], m[7], m[8],
        m[0], m[1], m[2], m[3], m[3], m[5], m[6], m[7], m[8]);
        counter++;
        m[0] = num;
        m[1] = - num - 0.1;
        m[2] = - num - 0.2;   
        m[3] = - num - 0.3;
        m[4] = - num - 0.4;
        m[5] = - num - 0.5;
        m[6] = - num - 0.6;
        m[7] = - num - 0.7;
        m[8] = - num - 0.8;
        num = num + 1;
         Serial.print("  size_written: "); Serial.println(size_written);
        if(size_written > 512){
           Serial.print("Error size is bigger than 512!!");
        }
       
        Serial.println(String(glove_measurement_buffer));
        Serial.println();
        pTxCharacteristic->setValue(glove_measurement_buffer);
        pTxCharacteristic->notify();

        delay(1000);
	  }

    // disconnecting
    if (!deviceConnected && oldDeviceConnected) {
        delay(500); // give the bluetooth stack the chance to get things ready
        pServer->startAdvertising(); // restart advertising
        Serial.println("start advertising");
        oldDeviceConnected = deviceConnected;
    }
    // connecting
    if (deviceConnected && !oldDeviceConnected) {
		// do stuff here on connecting
        oldDeviceConnected = deviceConnected;
    }
}


void toString(char buffer[],char finger){
    m[0] = num;
    m[1] = num + 0.1;
    m[2] = num + 0.2;   
    m[3] = num + 0.3;
    m[4] = num + 0.4;
    m[5] = num + 0.5;
    m[6] = num + 0.6;
    m[7] = num + 0.7;
    m[8] = num + 0.8;
    num = num + 1;

    /*
    const int buffer_size = 1 + snprintf(NULL, 0, "%c,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f,%.3f", 
    finger,m[0], m[1], m[2],m[3], m[3], m[5],m[6],m[7],m[8]);
    Serial.print("  buffer_size: ");Serial.print(buffer_size);
    assert(buffer_size > 0);
    char buf[buffer_size];
    */
}