Improved/added examples for the various current display shields including setup instruction header comments

examples/01.Basics/Blink/Blink.ino

@@ -5,12 +5,14 @@
  */
 
 void setup() {
-  pinMode(BUILTIN_LED, OUTPUT);  // initialize onboard LED as output
+  pinMode(LED_BUILTIN, OUTPUT);     // Initialize onboard LED as output
 }
 
 void loop() {
-  digitalWrite(BUILTIN_LED, HIGH);  // turn on LED with voltage HIGH
-  delay(1000);                      // wait one second
-  digitalWrite(BUILTIN_LED, LOW);   // turn off LED with voltage LOW
+  digitalWrite(LED_BUILTIN, LOW);   // Turn the LED on (Note that LOW is the voltage level
+                                    // but actually the LED is on; this is because 
+                                    // it is active low on the ESP-01)
+  delay(1000);                      // Wait one second
+  digitalWrite(LED_BUILTIN, HIGH);  // Turn the LED off by making the voltage HIGH
   delay(1000);                      // wait one second
 }

examples/04.Shields/Ambient_Light_Shield(BH1750)/BH1750_OLED_test/BH1750_OLED_test.ino

@@ -1,18 +1,37 @@
+//Install [claws/BH1750 Library](https://github.com/claws/BH1750) first.
+
 #include <Wire.h>
 #include <Adafruit_GFX.h>
 #include <Adafruit_SSD1306.h>
 #include <BH1750.h>
 
+#define SCREEN_WIDTH 64 // OLED display width, in pixels
+#define SCREEN_HEIGHT 48 // OLED display height, in pixels
+
+// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
+// SCL GPIO5
+// SDA GPIO4
 #define OLED_RESET 0  // GPIO0
-Adafruit_SSD1306 display(OLED_RESET);
+Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
+
+/*
+
+  BH1750 can be physically configured to use two I2C addresses:
+    - 0x23 (most common) (if ADD pin had < 0.7VCC voltage)
+    - 0x5C (if ADD pin had > 0.7VCC voltage)
+
+  Library uses 0x23 address as default, but you can define any other address.
+  If you had troubles with default value - try to change it to 0x5C.
 
+*/
 BH1750 light(0x23);
 
 void setup() {
 
   Serial.begin(115200);
 
-  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
+  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
+  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)); // Address 0x3C for 64x48
 
 }
 

examples/04.Shields/Barometric_Pressure_HP303B_Shield/HP303B_OLED_TEST/HP303B_OLED_TEST.ino

@@ -1,17 +1,26 @@
+//Install [LOLIN_HP303B_Library](https://github.com/wemos/LOLIN_HP303B_Library.git) first.
+
 #include <Wire.h>
 #include <Adafruit_GFX.h>
 #include <Adafruit_SSD1306.h>
 #include <LOLIN_HP303B.h>
 
 LOLIN_HP303B HP303B;
 
+#define SCREEN_WIDTH 64 // OLED display width, in pixels
+#define SCREEN_HEIGHT 48 // OLED display height, in pixels
+
+// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
+// SCL GPIO5
+// SDA GPIO4
 #define OLED_RESET -1
-Adafruit_SSD1306 display(OLED_RESET);
+Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
 
 void setup()
 {
 
-    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
+	// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
+	if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)); // Address 0x3C for 64x48
     display.setTextColor(WHITE);
 
     //Address of the HP303B (0x77 or 0x76)

examples/04.Shields/Barometric_Pressure_HP303B_Shield/simple/simple.ino

@@ -1,3 +1,5 @@
+//Install [LOLIN_HP303B_Library](https://github.com/wemos/LOLIN_HP303B_Library.git) first.
+
 #include <LOLIN_HP303B.h>
 
 LOLIN_HP303B HP303B;