fix compile

Author: ladyada

Adafruit_ESP32_Arduino_Demos/ESP32_sleeptest/ESP32_sleeptest.ino

@@ -1,20 +1,18 @@
 #include <Adafruit_NeoPixel.h>
-Adafruit_NeoPixel pixel(1, PIN_NEOPIXEL, NEO_GRB + NEO_KHZ800);
 
+#if defined(PIN_NEOPIXEL)
+  Adafruit_NeoPixel pixel(1, PIN_NEOPIXEL, NEO_GRB + NEO_KHZ800);
+#endif
 
 void setup() {
   Serial.begin(115200);
 
   // Turn on any internal power switches for TFT, NeoPixels, I2C, etc!
   enableInternalPower();
-
-  pixel.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
-  pixel.setBrightness(20); // not so bright
 }
 
 void loop() {
-  pixel.setPixelColor(0, 0xFFFFFF);
-  pixel.show();
+  LEDon();
   delay(1000);
 
   disableInternalPower();
@@ -28,6 +26,22 @@ void loop() {
   // we never reach here
 }
 
+void LEDon() {
+#if defined(PIN_NEOPIXEL)
+  pixel.begin(); // INITIALIZE NeoPixel
+  pixel.setBrightness(20); // not so bright
+  pixel.setPixelColor(0, 0xFFFFFF);
+  pixel.show();
+#endif
+}
+
+void LEDoff() {
+#if defined(PIN_NEOPIXEL)
+  pixel.setPixelColor(0, 0x0);
+  pixel.show();
+#endif
+}
+
 void enableInternalPower() {
 #if defined(ARDUINO_ADAFRUIT_QTPY_ESP32_PICO)
   pinMode(NEOPIXEL_POWER, OUTPUT);