Use BUILTIN_LED

libraries/esp8266/examples/Blink/Blink.ino

@@ -2,22 +2,23 @@
  ESP8266 Blink by Simon Peter
  Blink the blue LED on the ESP-01 module
  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
-
 void setup() {
-  pinMode(ledPin, OUTPUT);     // Initialize the ledPin as an output
+  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
 }
 
 // the loop function runs over and over again forever
 void loop() {
-  digitalWrite(ledPin, LOW);   // turn the LED on (Note that LOW is the voltage level
-                               // but actually the LED is on; this is because 
-                               // it is acive low on the ESP-01)
-  delay(1000);                 // Wait for a second
-  digitalWrite(ledPin, HIGH);  // Turn the LED off by making the voltage HIGH
-  delay(2000);                 // Wait for two seconds (to demonstrate the active low LED)
+  digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
+                                    // but actually the LED is on; this is because 
+                                    // it is acive low on the ESP-01)
+  delay(1000);                      // Wait for a second
+  digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
+  delay(2000);                      // Wait for two seconds (to demonstrate the active low LED)
 }