Use BUILTIN_LED

Author: probonopd

hardware/esp8266com/esp8266/libraries/esp8266/examples/BlinkWithoutDelay/BlinkWithoutDelay.ino

@@ -3,19 +3,20 @@
  Blink the blue LED on the ESP-01 module
  Based on the Arduino Blink without Delay example
  This example code is in the public domain
+ 
+ The blue LED on the ESP-01 module is connected to GPIO1 
+ (which is also the TXD pin; so we cannot use Serial.print() at the same time)
+ 
+ Note that this sketch uses BUILTIN_LED to find the pin with the internal LED
 */
 
-const int ledPin =  1;  // The blue LED on the ESP-01 module is connected to GPIO1 
-                        // (which is also the TXD pin; so we cannot use 
-                        // Serial.print() at the same time
-
 int ledState = LOW;     
 
 unsigned long previousMillis = 0;
 const long interval = 1000;
 
 void setup() {
-  pinMode(ledPin, OUTPUT);
+  pinMode(BUILTIN_LED, OUTPUT);
 }
 
 void loop()
@@ -27,7 +28,6 @@ void loop()
       ledState = HIGH;  // Note that this switches the LED *off*
     else
       ledState = LOW;   // Note that this switches the LED *on*
-    digitalWrite(ledPin, ledState);
+    digitalWrite(BUILTIN_LED, ledState);
   }
 }
-