Created
June 3, 2023 15:42
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| #include <BLEDevice.h> | |
| #include <BLEServer.h> | |
| #include <BLEUtils.h> | |
| #include <BLE2902.h> | |
| BLEServer* pServer = NULL; | |
| BLECharacteristic* pCharacteristic = NULL; | |
| bool deviceConnected = false; | |
| bool oldDeviceConnected = false; | |
| uint8_t value[6] = "hello"; | |
| #define SERVICE_UUID "8729034d-4a76-43bf-a8cf-6af50363617d" | |
| #define CHARACTERISTIC_UUID "f3091898-a3d2-4c59-bbee-b187c770a3d9" | |
| class MyServerCallbacks: public BLEServerCallbacks { | |
| void onConnect(BLEServer* pServer) { | |
| deviceConnected = true; | |
| BLEDevice::startAdvertising(); | |
| }; | |
| void onDisconnect(BLEServer* pServer) { | |
| deviceConnected = false; | |
| } | |
| }; | |
| void setup() { | |
| BLEDevice::init("ESP32"); | |
| // Create the BLE Server | |
| pServer = BLEDevice::createServer(); | |
| pServer->setCallbacks(new MyServerCallbacks()); | |
| // Create the BLE Service | |
| BLEService *pService = pServer->createService(SERVICE_UUID); | |
| // Create a BLE Characteristic | |
| pCharacteristic = pService->createCharacteristic( | |
| CHARACTERISTIC_UUID, | |
| BLECharacteristic::PROPERTY_READ | | |
| BLECharacteristic::PROPERTY_WRITE | | |
| BLECharacteristic::PROPERTY_NOTIFY | | |
| BLECharacteristic::PROPERTY_INDICATE | |
| ); | |
| // https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.descriptor.gatt.client_characteristic_configuration.xml | |
| // Create a BLE Descriptor | |
| pCharacteristic->addDescriptor(new BLE2902()); | |
| // Start the service | |
| pService->start(); | |
| // Start advertising | |
| BLEAdvertising *pAdvertising = BLEDevice::getAdvertising(); | |
| pAdvertising->addServiceUUID(SERVICE_UUID); | |
| pAdvertising->setScanResponse(false); | |
| pAdvertising->setMinPreferred(0x0); // set value to 0x00 to not advertise this parameter | |
| BLEDevice::startAdvertising(); | |
| } | |
| void loop() { | |
| // notify changed value | |
| if (deviceConnected) { | |
| pCharacteristic->setValue((uint8_t*)value, sizeof(value)); | |
| pCharacteristic->notify(); | |
| delay(10); // bluetooth stack will go into congestion, if too many packets are sent, in 6 hours test i was able to go as low as 3ms | |
| } | |
| // disconnecting | |
| if (!deviceConnected && oldDeviceConnected) { | |
| delay(500); // give the bluetooth stack the chance to get things ready | |
| pServer->startAdvertising(); // restart advertising | |
| oldDeviceConnected = deviceConnected; | |
| } | |
| // connecting | |
| if (deviceConnected && !oldDeviceConnected) { | |
| // do stuff here on connecting | |
| oldDeviceConnected = deviceConnected; | |
| } | |
| } |
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