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| 1 | +/* |
| 2 | + Video: https://www.youtube.com/watch?v=oCMOYS71NIU |
| 3 | + Based on Neil Kolban example for IDF: https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/tests/BLE%20Tests/SampleNotify.cpp |
| 4 | + Ported to Arduino ESP32 by Evandro Copercini |
| 5 | +
|
| 6 | + Create a BLE server that, once we receive a connection, will send periodic notifications. |
| 7 | + The service advertises itself as: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E |
| 8 | + Has a characteristic of: 6E400002-B5A3-F393-E0A9-E50E24DCCA9E - used for receiving data with "WRITE" |
| 9 | + Has a characteristic of: 6E400003-B5A3-F393-E0A9-E50E24DCCA9E - used to send data with "NOTIFY" |
| 10 | +
|
| 11 | + The design of creating the BLE server is: |
| 12 | + 1. Create a BLE Server |
| 13 | + 2. Create a BLE Service |
| 14 | + 3. Create a BLE Characteristic on the Service |
| 15 | + 4. Create a BLE Descriptor on the characteristic |
| 16 | + 5. Start the service. |
| 17 | + 6. Start advertising. |
| 18 | +
|
| 19 | + In this example rxValue is the data received (only accessible inside that function). |
| 20 | + And txValue is the data to be sent, in this example just a byte incremented every second. |
| 21 | +*/ |
| 22 | +#include <BLEDevice.h> |
| 23 | +#include <BLEServer.h> |
| 24 | +#include <BLEUtils.h> |
| 25 | +#include <BLE2902.h> |
| 26 | + |
| 27 | +BLECharacteristic *pCharacteristic; |
| 28 | +bool deviceConnected = false; |
| 29 | +uint8_t txValue = 0; |
| 30 | + |
| 31 | +// See the following for generating UUIDs: |
| 32 | +// https://www.uuidgenerator.net/ |
| 33 | + |
| 34 | +#define SERVICE_UUID "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID |
| 35 | +#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E" |
| 36 | +#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E" |
| 37 | + |
| 38 | + |
| 39 | +class MyServerCallbacks: public BLEServerCallbacks { |
| 40 | + void onConnect(BLEServer* pServer) { |
| 41 | + deviceConnected = true; |
| 42 | + }; |
| 43 | + |
| 44 | + void onDisconnect(BLEServer* pServer) { |
| 45 | + deviceConnected = false; |
| 46 | + } |
| 47 | +}; |
| 48 | + |
| 49 | +class MyCallbacks: public BLECharacteristicCallbacks { |
| 50 | + void onWrite(BLECharacteristic *pCharacteristic) { |
| 51 | + std::string rxValue = pCharacteristic->getValue(); |
| 52 | + |
| 53 | + if (rxValue.length() > 0) { |
| 54 | + Serial.println("*********"); |
| 55 | + Serial.print("Received Value: "); |
| 56 | + for (int i = 0; i < rxValue.length(); i++) |
| 57 | + Serial.print(rxValue[i]); |
| 58 | + |
| 59 | + Serial.println(); |
| 60 | + Serial.println("*********"); |
| 61 | + } |
| 62 | + } |
| 63 | +}; |
| 64 | + |
| 65 | + |
| 66 | +void setup() { |
| 67 | + Serial.begin(115200); |
| 68 | + |
| 69 | + // Create the BLE Device |
| 70 | + BLEDevice::init("UART Service"); |
| 71 | + |
| 72 | + // Create the BLE Server |
| 73 | + BLEServer *pServer = new BLEServer(); |
| 74 | + pServer->setCallbacks(new MyServerCallbacks()); |
| 75 | + |
| 76 | + // Create the BLE Service |
| 77 | + BLEService *pService = pServer->createService(SERVICE_UUID); |
| 78 | + |
| 79 | + // Create a BLE Characteristic |
| 80 | + pCharacteristic = pService->createCharacteristic( |
| 81 | + CHARACTERISTIC_UUID_TX, |
| 82 | + BLECharacteristic::PROPERTY_NOTIFY |
| 83 | + ); |
| 84 | + |
| 85 | + pCharacteristic->addDescriptor(new BLE2902()); |
| 86 | + |
| 87 | + BLECharacteristic *pCharacteristic = pService->createCharacteristic( |
| 88 | + CHARACTERISTIC_UUID_RX, |
| 89 | + BLECharacteristic::PROPERTY_WRITE |
| 90 | + ); |
| 91 | + |
| 92 | + pCharacteristic->setCallbacks(new MyCallbacks()); |
| 93 | + |
| 94 | + // Start the service |
| 95 | + pService->start(); |
| 96 | + |
| 97 | + // Start advertising |
| 98 | + pServer->getAdvertising()->start(); |
| 99 | + Serial.println("Waiting a client connection to notify..."); |
| 100 | +} |
| 101 | + |
| 102 | +void loop() { |
| 103 | + |
| 104 | + if (deviceConnected) { |
| 105 | + Serial.printf("*** Sent Value: %d ***\n", txValue); |
| 106 | + pCharacteristic->setValue(&txValue, 1); |
| 107 | + pCharacteristic->notify(); |
| 108 | + txValue++; |
| 109 | + } |
| 110 | + delay(1000); |
| 111 | +} |
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