Hello,

I have a program which communicates with android phone over serial bluetooth. (SerialBT) of ESP32. When my ESP32 is connected with my laptop, the bluetooth communication works fine. Here also after uploading the program first time I need to open the Serial monitor and only after that I can connect with ESP32 bluetooth. However after that if I remove and replug the laptop cable the Bluetooth communication works without Serial monitor.

When I power my ESP32 through external power supply, I am unable to connect with it from my app.  I have checked the voltage supplied by the external power and it is providing 3.1V. I have tried pressing Enable button to reset the ESP32 but it has not helped either. Any inputs are appreciated.

My code is as follows.

#include "BluetoothSerial.h"
#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif
BluetoothSerial SerialBT;
String t,h;
int tval, hval;
int thresholdH=0;
int thresholdT=0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  SerialBT.begin("ESP32smarshoe"); //Bluetooth device name
  Serial.println("The device started, now you can pair it with bluetooth!");
}
void loop() {
  // put your main code here, to run repeatedly:
  t="T";
 h="H";
 tval=analogRead(34);
 hval=analogRead(35);
 t+=tval;
 t+="T";
 t+=hval;
 Serial.println(t);
 SerialBT.println(t);
 delay(200);
}

Manoj