ESP32 | BLE | SERVER - CLIENT

Esp32_BLE_to_BLE/ESP32_ble_client_v2/ESP32_ble_client_v2.ino

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+/**
+ * A BLE client example that is rich in capabilities.
+ * There is a lot new capabilities implemented.
+ * author unknown
+ * updated by chegewara
+ */
+
+
+#include "Adafruit_GFX.h"
+#include "Adafruit_ILI9341.h"
+
+#define TFT_DC 17
+#define TFT_CS 5
+#define TFT_MOSI 23
+#define TFT_CLK 18
+#define TFT_RST 4
+#define TFT_MISO 19
+
+static Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);
+static int offset = 30;
+static int foundDeviceCnt = 0;
+static int marginY = 6;
+
+#define nextButtonPin 12
+#define selectButtonPin 14
+int cntPos = 1;
+int prevPos = 1;
+
+#include "BLEDevice.h"
+//#include "BLEScan.h"
+
+#define ARRAYSIZE 10
+BLEAdvertisedDevice results[ARRAYSIZE];
+
+// The remote service we wish to connect to.
+static BLEUUID serviceUUID("4fafc201-1fb5-459e-8fcc-c5c9c331914b");
+// The characteristic of the remote service we are interested in.
+static BLEUUID    charUUID("beb5483e-36e1-4688-b7f5-ea07361b26a8");
+
+static boolean doConnect = false;
+static boolean connected = false;
+static boolean doScan = false;
+static BLERemoteCharacteristic* pRemoteCharacteristic;
+static BLEAdvertisedDevice* myDevice;
+
+static void notifyCallback(
+  BLERemoteCharacteristic* pBLERemoteCharacteristic,
+  uint8_t* pData,
+  size_t length,
+  bool isNotify) {
+    Serial.print("Notify callback for characteristic ");
+    Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str());
+    Serial.print(" of data length ");
+    Serial.println(length);
+    Serial.print("data: ");
+    Serial.println((char*)pData);
+
+    String strData;
+    strData.reserve(length);
+    for(int i=0; i<length; i++){
+      strData +=(char)pData[i];
+    }
+    printData(strData);
+}
+
+class MyClientCallback : public BLEClientCallbacks {
+  void onConnect(BLEClient* pclient) {
+  }
+
+  void onDisconnect(BLEClient* pclient) {
+    connected = false;
+    Serial.println("onDisconnect");
+  }
+};
+
+bool connectToServer() {
+    Serial.print("Forming a connection to ");
+    Serial.println(myDevice->getAddress().toString().c_str());
+    
+    BLEClient*  pClient  = BLEDevice::createClient();
+    Serial.println(" - Created client");
+
+    pClient->setClientCallbacks(new MyClientCallback());
+
+    // Connect to the remove BLE Server.
+    pClient->connect(myDevice);  // if you pass BLEAdvertisedDevice instead of address, it will be recognized type of peer device address (public or private)
+    Serial.println(" - Connected to server");
+
+    // Obtain a reference to the service we are after in the remote BLE server.
+    BLERemoteService* pRemoteService = pClient->getService(serviceUUID);
+    if (pRemoteService == nullptr) {
+      Serial.print("Failed to find our service UUID: ");
+      Serial.println(serviceUUID.toString().c_str());
+      pClient->disconnect();
+      return false;
+    }
+    Serial.println(" - Found our service");
+
+
+    // Obtain a reference to the characteristic in the service of the remote BLE server.
+    pRemoteCharacteristic = pRemoteService->getCharacteristic(charUUID);
+    if (pRemoteCharacteristic == nullptr) {
+      Serial.print("Failed to find our characteristic UUID: ");
+      Serial.println(charUUID.toString().c_str());
+      pClient->disconnect();
+      return false;
+    }
+    Serial.println(" - Found our characteristic");
+
+    // Read the value of the characteristic.
+    if(pRemoteCharacteristic->canRead()) {
+      std::string value = pRemoteCharacteristic->readValue();
+      Serial.print("The characteristic value was: ");
+      Serial.println(value.c_str());
+    }
+
+    if(pRemoteCharacteristic->canNotify())
+      pRemoteCharacteristic->registerForNotify(notifyCallback);
+
+    connected = true;
+}
+/**
+ * Scan for BLE servers and find the first one that advertises the service we are looking for.
+ */
+class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
+ /**
+   * Called for each advertising BLE server.
+   */
+
+  public:
+  MyAdvertisedDeviceCallbacks(){
+    printStatus("SEARCHING...");
+  }
+   
+  void onResult(BLEAdvertisedDevice advertisedDevice) {
+    printStatus("...RESULT");
+    
+    Serial.print("BLE Advertised Device found: ");
+    //Serial.println(advertisedDevice.toString().c_str());
+
+    String deviceName = advertisedDevice.getName().c_str();
+    if(deviceName.length() >1){
+      results[foundDeviceCnt] = advertisedDevice;
+      foundDeviceCnt++;
+      printContent(deviceName);
+    }
+
+    // We have found a device, let us now see if it contains the service we are looking for.
+//    if (advertisedDevice.haveServiceUUID() && advertisedDevice.isAdvertisingService(serviceUUID)) {
+//
+//      BLEDevice::getScan()->stop();
+//      myDevice = new BLEAdvertisedDevice(advertisedDevice);
+//      doConnect = true;
+//      doScan = true;
+//
+//    } // Found our server
+  } // onResult
+
+  void printContent(String deviceName){
+    int drawingOffsetY = offset * foundDeviceCnt;
+    tft.fillRect(0, drawingOffsetY, 240, 320, ILI9341_WHITE);
+    tft.setCursor(16, drawingOffsetY + marginY);
+    tft.setTextColor(ILI9341_BLACK);
+    tft.setTextSize(1);
+    tft.print(deviceName);
+  }
+
+  void printStatus(String statusText){
+    tft.fillRect(0,0,240,30, ILI9341_DARKGREY);
+    tft.setCursor(6, 6);
+    tft.setTextColor(ILI9341_WHITE);
+    tft.setTextSize(2);
+    tft.print(statusText);
+  }
+}; // MyAdvertisedDeviceCallbacks
+
+
+void setup() {
+  Serial.begin(115200);
+  Serial.println("Starting Arduino BLE Client application...");
+  
+
+  tft.begin();
+  tft.setRotation(0);
+  tft.fillScreen(ILI9341_WHITE);
+
+  pinMode(nextButtonPin, INPUT);
+  pinMode(selectButtonPin, INPUT);
+
+  BLEDevice::init("");
+
+  // Retrieve a Scanner and set the callback we want to use to be informed when we
+  // have detected a new device.  Specify that we want active scanning and start the
+  // scan to run for 5 seconds.
+  BLEScan* pBLEScan = BLEDevice::getScan();
+  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());
+  pBLEScan->setInterval(1349);
+  pBLEScan->setWindow(449);
+  pBLEScan->setActiveScan(true);
+  pBLEScan->start(3, false);
+} // End of setup.
+
+
+// This is the Arduino main loop function.
+void loop() {
+
+  // If the flag "doConnect" is true then we have scanned for and found the desired
+  // BLE Server with which we wish to connect.  Now we connect to it.  Once we are 
+  // connected we set the connected flag to be true.
+  if (doConnect == true) {
+    if (connectToServer()) {
+      printConnected(myDevice->getName().c_str());
+      Serial.println("We are now connected to the BLE Server.");
+    } else {
+      Serial.println("We have failed to connect to the server; there is nothin more we will do.");
+    }
+    doConnect = false;
+  }
+
+  // If we are connected to a peer BLE Server, update the characteristic each time we are reached
+  // with the current time since boot.
+  if (connected) {
+    String newValue = "Time since boot: " + String(millis()/1000);
+    Serial.println("Setting new characteristic value to \"" + newValue + "\"");
+    
+    // Set the characteristic's value to be the array of bytes that is actually a string.
+    pRemoteCharacteristic->writeValue(newValue.c_str(), newValue.length());
+  }else if(doScan){
+    BLEDevice::getScan()->start(0);  // this is just eample to start scan after disconnect, most likely there is better way to do it in arduino
+  }
+
+  buttonsCallBack();
+  delay(250); // Delay a second between loops.
+} // End of loop
+
+void buttonsCallBack(){
+  int nextButtonState = digitalRead(nextButtonPin);
+  int selectButtonState = digitalRead(selectButtonPin);
+
+  if(selectButtonState == HIGH){
+    myDevice = new BLEAdvertisedDevice(results[cntPos-1]);
+    doConnect = true;
+
+    int drawingOffsetY = offset * prevPos + 8;
+    tft.drawCircle(6, drawingOffsetY, 6, ILI9341_WHITE);
+  }
+
+  if(nextButtonState == HIGH){
+    cntPos ++;
+  }
+
+  if(cntPos > foundDeviceCnt){
+    cntPos = 1;
+  }
+
+  if(!connected){
+    if(prevPos != cntPos){
+      int drawingOffsetY = offset * prevPos + 8;
+      tft.drawCircle(6, drawingOffsetY, 6, ILI9341_WHITE);
+    }
+
+    if(cntPos != 0){
+      int drawingOffsetY = offset * cntPos + 8;
+      tft.drawCircle(6, drawingOffsetY, 6, ILI9341_RED);
+
+      prevPos = cntPos;
+    }
+  }
+}
+
+void printConnected(String deviceName){
+  tft.fillRect(0, 0, 240, 320, ILI9341_WHITE);
+  tft.fillRect(0, 0, 240, 30, ILI9341_DARKGREY);
+  tft.setCursor(6,6);
+  tft.setTextColor(ILI9341_WHITE);
+  tft.setTextSize(2);
+  tft.print("Connected");
+
+  tft.setCursor(6, 36);
+  tft.setTextColor(ILI9341_BLACK);
+  tft.setTextSize(2);
+  tft.print(deviceName);
+}
+
+void printData(String notiData){
+  tft.fillRect(0, 50, 240, 100, ILI9341_WHITE);
+  tft.setCursor(6, 70);
+  tft.setTextColor(ILI9341_RED);
+  tft.setTextSize(2);
+  tft.print(notiData);
+}