126 lines
3.8 KiB
C++
126 lines
3.8 KiB
C++
/*
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Video: https://www.youtube.com/watch?v=oCMOYS71NIU
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Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleNotify.cpp
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Ported to Arduino ESP32 by Evandro Copercini
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Create a BLE server that, once we receive a connection, will send periodic notifications.
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The service advertises itself as: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E
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Has a characteristic of: 6E400002-B5A3-F393-E0A9-E50E24DCCA9E - used for receiving data with "WRITE"
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Has a characteristic of: 6E400003-B5A3-F393-E0A9-E50E24DCCA9E - used to send data with "NOTIFY"
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The design of creating the BLE server is:
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1. Create a BLE Server
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2. Create a BLE Service
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3. Create a BLE Characteristic on the Service
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4. Create a BLE Descriptor on the characteristic
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5. Start the service.
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6. Start advertising.
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In this example rxValue is the data received (only accessible inside that function).
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And txValue is the data to be sent, in this example just a byte incremented every second.
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*/
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#include <BLEDevice.h>
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#include <BLEServer.h>
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#include <BLEUtils.h>
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#include <BLE2902.h>
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BLEServer *pServer = NULL;
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BLECharacteristic * pTxCharacteristic;
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bool deviceConnected = false;
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bool oldDeviceConnected = false;
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uint8_t txValue = 0;
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// See the following for generating UUIDs:
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// https://www.uuidgenerator.net/
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#define SERVICE_UUID "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID
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#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
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#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"
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class MyServerCallbacks: public BLEServerCallbacks {
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void onConnect(BLEServer* pServer) {
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deviceConnected = true;
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};
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void onDisconnect(BLEServer* pServer) {
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deviceConnected = false;
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}
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};
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class MyCallbacks: public BLECharacteristicCallbacks {
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void onWrite(BLECharacteristic *pCharacteristic) {
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std::string rxValue = pCharacteristic->getValue();
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if (rxValue.length() > 0) {
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Serial.println("*********");
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Serial.print("Received Value: ");
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for (int i = 0; i < rxValue.length(); i++)
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Serial.print(rxValue[i]);
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Serial.println();
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Serial.println("*********");
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}
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}
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};
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void setup() {
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Serial.begin(115200);
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// Create the BLE Device
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BLEDevice::init("UART Service");
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// Create the BLE Server
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pServer = BLEDevice::createServer();
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pServer->setCallbacks(new MyServerCallbacks());
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// Create the BLE Service
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BLEService *pService = pServer->createService(SERVICE_UUID);
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// Create a BLE Characteristic
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pTxCharacteristic = pService->createCharacteristic(
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CHARACTERISTIC_UUID_TX,
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BLECharacteristic::PROPERTY_NOTIFY
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);
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pTxCharacteristic->addDescriptor(new BLE2902());
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BLECharacteristic * pRxCharacteristic = pService->createCharacteristic(
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CHARACTERISTIC_UUID_RX,
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BLECharacteristic::PROPERTY_WRITE
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);
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pRxCharacteristic->setCallbacks(new MyCallbacks());
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// Start the service
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pService->start();
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// Start advertising
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pServer->getAdvertising()->start();
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Serial.println("Waiting a client connection to notify...");
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}
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void loop() {
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if (deviceConnected) {
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pTxCharacteristic->setValue(&txValue, 1);
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pTxCharacteristic->notify();
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txValue++;
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delay(10); // bluetooth stack will go into congestion, if too many packets are sent
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}
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// disconnecting
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if (!deviceConnected && oldDeviceConnected) {
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delay(500); // give the bluetooth stack the chance to get things ready
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pServer->startAdvertising(); // restart advertising
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Serial.println("start advertising");
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oldDeviceConnected = deviceConnected;
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}
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// connecting
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if (deviceConnected && !oldDeviceConnected) {
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// do stuff here on connecting
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oldDeviceConnected = deviceConnected;
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}
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}
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