ESP32 cannot serial monitor [closed]

Question

I use esp32 devkit v1 . I code follwing this picture.

const int vavle = 1;
int d = 1;

void setup()
{
  Serial.begin(115200);
  delay(2000);
  while (!Serial);
  Serial.println();
  pinMode(vavle,OUTPUT);
  Serial.println(d);
}

void loop()
{
  Serial.print("Open Vavle");
  digitalWrite(vavle,HIGH);
  delay(3000);
  digitalWrite(vavle,LOW);
  delay(1000);
  Serial.print("Close Vavle");
}

but serial monitor has error when use serial monitor it show me square . I confirm select true board rate. you can solve this problem .

Answer 1

The GPIO1 pin you are trying to use with const int vavle = 1; ... pinMode(vavle, OUTPUT); is the same pin that carries serial data to the PC.

From the pinout:

Their schematic link is broken, but if you find schematic for pretty much any similar board using this module you'll see GPIO1/U0TXD connected to a serial transceiver chip which is then connected to the USB port.

You need choose some other pin. There are pin guides and official documentation containing the same details that you can use to figure out which GPIO to use. GPIO numbers 16 through 33 inclusive are all output-capable and seem to have no special requirements, so they make sense to choose from.