How to change supervision timeout of ble device esp32 - bluetooth-lowenergy

Question

I am using two esp32, one configured as server and the other as client,the server takes about 3 seconds to detect disconnection of client (when it’s out of range or turned off), while client takes 6 seconds to detect disconnection of server, how do I set the supervision timeout so that Both sever and client detect disconnection after only 1 sec
Here’s the server code :
#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
#define SERVICE_UUID "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"
bool deviceConnected = false;
//Setup callbacks onConnect and onDisconnect
class MyServerCallbacks: public BLEServerCallbacks {
void onConnect(BLEServer* pServer) {
deviceConnected = true;
};
void onDisconnect(BLEServer* pServer) { // this method takes 6 sec when I’m using two esps (when esp client disconnects from server ) but it’s immediate when my phone disconnects from server
deviceConnected = false;
Serial.println("Client has disconnected");
Serial.println("readvertising");
BLEDevice::getAdvertising()->start(); // start advertising after disconnect
}
};
void setup() {
Serial.begin(115200);
Serial.println("Starting BLE work!");
BLEDevice::init("Long name works now");
BLEServer *pServer = BLEDevice::createServer();
BLEService *pService = pServer->createService(SERVICE_UUID);
BLECharacteristic *pCharacteristic = pService->createCharacteristic(
CHARACTERISTIC_UUID,
BLECharacteristic::PROPERTY_READ |
BLECharacteristic::PROPERTY_WRITE
);
pCharacteristic->setValue("Hello World says Neil");
pService->start();
// BLEAdvertising *pAdvertising = pServer->getAdvertising(); // this still is working for backward compatibility
BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
pAdvertising->addServiceUUID(SERVICE_UUID);
pAdvertising->setScanResponse(true);
pAdvertising->setMinPreferred(0x06); // functions that help with iPhone connections issue
pAdvertising->setMinPreferred(0x12);
BLEDevice::startAdvertising();
Serial.println("Characteristic defined! Now you can read it in your phone!");
}
void loop() {
// put your main code here, to run repeatedly:
if(deviceConnected){
//code executed only when client is connected
}
}
I’ve been told to use this function
void BLEServer::updateConnParams(esp_bd_addr_t remote_bda, uint16_t minInterval, uint16_t maxInterval, uint16_t latency, uint16_t timeout)
{
esp_ble_conn_update_params_t conn_params;
memcpy(conn_params.bda, remote_bda, sizeof(esp_bd_addr_t));
conn_params.min_int = minInterval;
conn_params.max_int = maxInterval;
conn_params.latency = latency;
conn_params.timeout = timeout;
esp_ble_gap_update_conn_params(&conn_params);
}
When I do I get this error
multiple definition of `BLEServer::updateConnParams(unsigned char*, unsigned short, unsigned short, unsigned short, unsigned short)'
BLE_Server.ino:31: first defined here

Answer 1

Is it possible you redeclared the function in your code? It’s already a part of the BLEServer library.
We miss a lot of code, but just call the BLEServer::updateConnParams after you made your connection and define the parameters you need. The min/max interval can be the same, or just use the interval which suites you, and make sure max interval * 1.25 ms * latency (max missed calls before connection would be defined as lost) is not greater than the timeout (value * 10 ms)