diff --git a/ESP32-IDF_ESPNOW-Transmitter/main/config.h b/ESP32-IDF_ESPNOW-Transmitter/main/config.h
index 88aacee37..675323bdc 100644
--- a/ESP32-IDF_ESPNOW-Transmitter/main/config.h
+++ b/ESP32-IDF_ESPNOW-Transmitter/main/config.h
@@ -8,6 +8,8 @@
     Configuration variables
 */
 
+#define SYS_LED_GPIO  (10)  // 10 GPIO of on-board LED
+
 /*  ============================
     Joystick
     ============================