BTClassic: discover() & connect()

[BlackWolfDEsign]

Board

ESP32 Dev Module

Device Description

nothing

Hardware Configuration

only BT-connection

Version

2.0.10

IDE Name

Arduino IDE

Operating System

Win 10

Flash frequency

80Mhz

PSRAM enabled

yes

Upload speed

115200

Description

in my loop(): I want to discover() available clients. after that, i want to connect() to them and after that i want to repeat this.

If I use the discover()-part only, it shows all available clients, works as expected....

If i use connect("DEVICE_NAME") only, it works perfectly. Also with multiple clients....

If I use both, the discover()-function works on the first pass, but after connect(DEVICE_NAME), the discover()-function is broken... (I don't get any "active" devices anymore) so I tried so many different approaches, but I didn't find a solution....

If I put the discover()-part in setup(), everything works fine, but i want to update the list of active clients, so i put this part in loop().

a connect() after discover() will stop discover()!?!

Sketch

// BT
#include "BluetoothSerial.h"
BluetoothSerial SerialBT;
BluetoothSerial SerialBT2; // this was only a desperate test...

#include "ListLib.h"
List<String> list;

#define BT_DISCOVER_TIME 10000

void setup() {
  Serial.begin(9600);
}

void loop() {
  SerialBT.begin("MASTER", true); // normally in setup(), i know...
  SerialBT.discover(BT_DISCOVER_TIME);
  BTScanResults* pScanResults = SerialBT.getScanResults();
  Serial.println(pScanResults->getCount());

  for (int i = 0; i < pScanResults->getCount(); i++) {
    BTAdvertisedDevice* pDevice = pScanResults->getDevice(i);
    String deviceName = pDevice->getName().c_str();
    if (deviceName.startsWith("SLAVE")) {
        delay(200);
        list.Add(deviceName);
        Serial.println(list[i]);
    }
  }
  SerialBT.discoverClear();
  SerialBT.disconnect();
  SerialBT.end();




  SerialBT2.begin("MASTER", true);
  for (int i = 0; i < list.Count(); i++) {
    SerialBT2.connect(list[i]);
    SerialBT2.println("REQUEST");
    delay(200);
    Serial.println(SerialBT2.readStringUntil('\n'));
    SerialBT2.disconnect();
  }
  SerialBT2.end();
  list.Clear();
}

Debug Message

none? ;/

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

edit: for now, i have moved the discover part to setup() and every 30minutes the esp is restarted... it's not the best approach, but it works... conclusion: discover and connect do not work together

[SuGlider]

@PilnyTomas PTAL, thanks!

[PilnyTomas]

Hi, I have slightly modified your code and added a few debug outputs and it is working. I'm using a second ESP32 with the example SerialToSerialBT with the name changed, to begin with SLAVE as expected by your code.
Can you please test my code to see if it works for you?

#include "BluetoothSerial.h"
BluetoothSerial SerialBT;
BluetoothSerial SerialBT2; // this was only a desperate test...

#include "ListLib.h"
List<String> list;

#define BT_DISCOVER_TIME 10000

void setup() {
  Serial.begin(115200);
}

void loop() {
  SerialBT.begin("MASTER", true); // normally in setup(), i know...
  SerialBT.discover(BT_DISCOVER_TIME);
  BTScanResults* pScanResults = SerialBT.getScanResults();
  Serial.println(pScanResults->getCount());

  Serial.printf("DEBUG: got %d results\n", pScanResults->getCount());
  for (int i = 0; i < pScanResults->getCount(); i++) {
    BTAdvertisedDevice* pDevice = pScanResults->getDevice(i);
    String deviceName = pDevice->getName().c_str();
    if (deviceName.startsWith("SLAVE")) {
        list.Add(deviceName);
        Serial.printf("DEBUG: Added to list \"%s\"\n", list[i].c_str());
    }
  }
  SerialBT.discoverClear();
  SerialBT.disconnect();
  SerialBT.end();

  SerialBT2.begin("MASTER", true);
  for (int i = 0; i < list.Count(); i++) {
    Serial.printf("DEBUG: Connecting to [%d] \"%s\"\n", i, list[i].c_str());
    if(SerialBT2.connect(list[i])){
      Serial.printf("DEBUG: Connected\n");
      SerialBT2.println("REQUEST");
      Serial.println(SerialBT2.readStringUntil('\n'));
      SerialBT2.disconnect();
    }else{
      Serial.printf("DEBUG: Could not connect\n");
    }
  }
  SerialBT2.end();
  list.Clear();
  delay(10); // Feed the watchdog, otherwise will crash with "st:0x7 (TG0WDT_SYS_RESET)"
}

[BlackWolfDEsign]

21:15:37.686 -> DEBUG: got 1 results
21:15:37.717 -> DEBUG: Added to list "POD_SLAVE_A0B765596A92"
21:15:38.282 -> DEBUG: Connecting to [0] "POD_SLAVE_A0B765596A92"
21:15:39.440 -> DEBUG: Connected
21:15:40.440 ->
21:15:41.881 -> 0
21:15:41.881 -> DEBUG: got 0 results

without requesting it is working like mine D:

slave loop

void loop() {
  if (SerialBT.available()) {
    String CMD = SerialBT.readString();
    CMD.trim();

    if (CMD == "REQUEST") {
      // Befehl zum Abrufen des JSON-Strings
      String jsonString = getJSONData();  // JSON-Data
      // Daten an den Master senden
      SerialBT.println(jsonString);
      Serial.println(jsonString);
    }
  }
}

After the first REQUEST, the slave sends a one-time response, after which the master dies (see "DEBUG" message above)

with

      SerialBT2.println("REQUEST");
      delay(600);

I also get the message on the master, but only once

21:36:50.550 -> DEBUG: got 1 results
21:36:50.550 -> DEBUG: Added to list "POD_SLAVE_A0B765596A92"
21:36:51.136 -> DEBUG: Connecting to [0] "POD_SLAVE_A0B765596A92"
21:36:53.937 -> DEBUG: Connected
21:36:55.042 -> {"deviceMode":"SLAVE","deviceType":"POD","deviceMAC":"A0B765596A92","humidity":"nan","temperature":"nan","lux":"2.50"}

21:36:56.560 -> 0
21:36:56.560 -> DEBUG: got 0 results

[PilnyTomas]

Ok, the discover is failing on the first test:

arduino-esp32/libraries/BluetoothSerial/src/BluetoothSerial.cpp

Line 1095 in 099b432

if (timeoutMs < MIN_INQ_TIME || timeoutMs > MAX_INQ_TIME || strlen(_remote_name) || _isRemoteAddressSet)

[E][BluetoothSerial.cpp:1173] discover(): Failed if (timeoutMs(10000) < MIN_INQ_TIME(1280) || timeoutMs(10000) > MAX_INQ_TIME(61440) || strlen(_remote_name)(14) || _isRemoteAddressSet(1)){