Add Let's Build on AWS IoT episode sample code

Author: anacunha

.gitignore

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+.DS_Store
+secrets.h

README.md

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-## My Project
+# Let's Build on AWS – IoT
 
-TODO: Fill this README out!
+## Setup
 
-Be sure to:
+### Arduino IDE
 
-* Change the title in this README
-* Edit your repository description on GitHub
+Download install Arduino IDE: https://www.arduino.cc/en/software
+
+### ESP32 Support for Arduino
+
+1. Launch Arduino IDE
+2. Open Preferences
+3. Enter `https://dl.espressif.com/dl/package_esp32_index.json` into *Additional Boards Manager URLs* field
+4. Click the *OK* button ![Additional Boards Manager URLs on Arduino IDE Preferences](images/additional-boards-manager.png)
+5. Go to Tools > Board > Boards Manager Manager...
+6. Search for *esp32*
+7. Install *esp32* by **Espressif Systems** ![Install esp32 on Arduino IDE Boards Manager](images/esp32.png)
+8. Go to Tools > Board > ESP32 Arduino and select *ESP32 Dev Module* ![Select ESP32 Dev Module on Tools > Board menu](images/esp32-dev-module.png)
+
+### Additional Libraries
+
+Some of the sample code will require additional libraries. You can install them through the Arduino IDE Library Manager:
+
+- Launch Arduino IDE
+- Go to Tools > Manage Libraries... to open the Library Manager ![Select Manage Libries on Tools menu](images/library-manager.png)
+
+#### MQTT
+
+- Search for *lwmqtt*
+- Install [*MQTT*](https://github.com/256dpi/arduino-mqtt) by **Joel Gahwiler** ![Install MQTT library on Arduino IDE Library Manager](images/libraries/mqtt.png)
+
+#### ArduinoJson
+
+- Search for *ArduinoJson*
+- Install [*ArduinoJson*](https://github.com/bblanchon/ArduinoJson) by **Benoit Blanchon** ![Install ArduinoJson library on Arduino IDE Library Manager](images/libraries/arduinojson.png)
+
+#### ClosedCube HDC1080
+
+- Search for *1080*
+- Install [*ClosedCube HDC1080*](https://github.com/closedcube/ClosedCube_HDC1080_Arduino) by **ClosedCube** ![Install ClosedCube HDC1080 library on Arduino IDE Library Manager](images/libraries/closedcube-hdc1080.png)
 
 ## Security
 

images/additional-boards-manager.png

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+/*
+  ESP32 Blink
+
+  Blink the built-in LED on ESP32 Dev Kit V1
+*/
+
+// Built-in LED on ESP32 is connected to pin number 2
+const int LED_BUILTIN = 2;
+
+// the setup function runs once when you press reset or power the board
+void setup() {
+  // initialize digital pin LED_BUILTIN as an output.
+  pinMode(LED_BUILTIN, OUTPUT);
+}
+
+// the loop function runs over and over again forever
+void loop() {
+  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
+  delay(1000);                       // wait for a second
+  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
+  delay(1000);                       // wait for a second
+}

images/esp32-dev-module.png

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+void connectAWS() {
+  // Configure WiFiClientSecure to use the AWS IoT device credentials
+  net.setCACert(AWS_CERT_CA);
+  net.setCertificate(AWS_CERT_CRT);
+  net.setPrivateKey(AWS_CERT_PRIVATE);
+
+  // Connect to the MQTT broker on the AWS endpoint
+  client.begin(AWS_IOT_ENDPOINT, 8883, net);
+
+  Serial.println("Connecting to AWS IOT");
+
+  while (!client.connect(AWS_THING_NAME)) {
+    Serial.print(".");
+    delay(100);
+  }
+
+  Serial.println("AWS IoT Connected!");
+}

images/esp32.png

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+const char* ssid = "Let's Build on AWS";
+const char* password = "lets-build";
+
+void connectWiFi() {
+  Serial.println("Connecting");
+  WiFi.begin(ssid, password);
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println("Ready");
+  Serial.print("IP address: ");
+  Serial.println(WiFi.localIP());
+}

images/libraries/arduinojson.png

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+#include <WiFiClientSecure.h>
+#include <MQTTClient.h>
+
+#include "secrets.h"
+
+#define AWS_THING_NAME "esp32"
+#define AWS_IOT_PUBLISH_TOPIC   "foodstuff/publish"
+#define AWS_IOT_SUBSCRIBE_TOPIC "foodstuff/subscribe"
+
+WiFiClientSecure net = WiFiClientSecure();
+MQTTClient client = MQTTClient(512);
+
+// the setup function runs once when you power the board or press reset
+void setup() {
+  Serial.begin(115200);
+  connectWiFi();
+  connectAWS();
+
+  // Subscribe to a topic
+  client.subscribe(AWS_IOT_SUBSCRIBE_TOPIC);
+
+  // Create a message handler
+  client.onMessage(messageHandler);
+}
+
+void messageHandler(String &topic, String &payload) {
+  Serial.println("Receiving MQTT message:");
+  Serial.println(topic + " " + payload);
+}
+
+// the loop function runs over and over again forever
+void loop() {
+  // Sends and receives packets
+  client.loop();
+
+  // Publish to a topic
+  client.publish(AWS_IOT_PUBLISH_TOPIC, "{\"message\": \"Hello from ESP32!\"}");
+}

images/libraries/closedcube-hdc1080.png

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+void connectAWS() {
+  // Configure WiFiClientSecure to use the AWS IoT device credentials
+  net.setCACert(AWS_CERT_CA);
+  net.setCertificate(AWS_CERT_CRT);
+  net.setPrivateKey(AWS_CERT_PRIVATE);
+
+  // Connect to the MQTT broker on the AWS endpoint
+  client.begin(AWS_IOT_ENDPOINT, 8883, net);
+
+  Serial.println("Connecting to AWS IOT");
+
+  while (!client.connect(AWS_THING_NAME)) {
+    Serial.print(".");
+    delay(100);
+  }
+
+  Serial.println("AWS IoT Connected!");
+}

images/libraries/mqtt.png

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+const char* ssid = "Let's Build on AWS";
+const char* password = "lets-build";
+
+void connectWiFi() {
+  Serial.println("Connecting");
+  WiFi.begin(ssid, password);
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(500);
+    Serial.print(".");
+  }
+  Serial.println("Ready");
+  Serial.print("IP address: ");
+  Serial.println(WiFi.localIP());
+}

images/library-manager.png

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+#include <WiFiClientSecure.h>
+#include <MQTTClient.h>
+#include <ArduinoJson.h>
+
+#include "secrets.h"
+
+#define AWS_THING_NAME "esp32"
+#define AWS_IOT_PUBLISH_BUTTON "callwaiter/button"
+
+#define TABLE_NUMBER 13  // table number
+#define BUTTON_PIN 23    // push-buton pin
+
+WiFiClientSecure net = WiFiClientSecure();
+MQTTClient client = MQTTClient(512);
+volatile unsigned long lastCallWaiterTime = 0; // Records last call waiter time
+volatile bool callWaiter = false;              // Flag to call waiter
+
+void setup() {
+  Serial.begin(115200);
+
+  // Initialize the push-button pin as an input
+  // with an internal pull-up resistor enabled:
+  pinMode(BUTTON_PIN, INPUT_PULLUP);
+
+  // When push-button pin goes from high to low (FALLING),
+  // call the buttonPressed() function.
+  attachInterrupt(BUTTON_PIN, buttonPressed, FALLING);
+
+  connectWiFi();
+  connectAWS();
+}
+
+void buttonPressed() {
+  unsigned long currentTime = millis();
+
+  // We want to avoid calling the waiter multiple times at once
+  if (currentTime - lastCallWaiterTime > 1000) {
+    callWaiter = true;
+    lastCallWaiterTime = currentTime;
+  }
+}
+
+void loop()  {
+  // Sends and receives packets
+  client.loop();
+
+  if (callWaiter) {
+    Serial.println("Calling waiter...");
+
+    // Create JSON document
+    StaticJsonDocument<200> json;
+    json["tableNumber"] = TABLE_NUMBER;
+    json["deviceTime"] = millis();
+    json["deviceName"] = AWS_THING_NAME;
+
+    // Serialize JSON
+    char jsonBuffer[128];
+    serializeJson(json, jsonBuffer);
+
+    // Publish message to callwaiter/button topic
+    client.publish(AWS_IOT_PUBLISH_BUTTON, jsonBuffer);
+
+    // Reset the callWaiter flag
+    callWaiter = false;
+  }
+}

module-1/hello-world/hello-world.ino

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+#define BUTTON_PIN 23   // push-button pin
+
+int buttonState = 0;    // variable for reading the push-button status
+
+// the setup routine runs once when you press reset:
+void setup() {
+  // initialize serial communication at 115200 bits per second:
+  Serial.begin(115200);
+
+  // initialize the push-button pin as an input
+  // and enable the internal pull-up resistor
+  pinMode(BUTTON_PIN, INPUT_PULLUP);
+}
+
+// the loop routine runs over and over again forever:
+void loop() {
+  // read the state of the push-button value:
+  buttonState = digitalRead(BUTTON_PIN);
+
+  // check if the push-button is pressed
+  // if it is, the buttonState is LOW:
+  if (buttonState == LOW) {
+    Serial.println("Button Down");
+  } else {
+    Serial.println("Button Up");
+  }
+}

module-1/pub-sub-mqtt/AWS.ino

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+void connectAWS()
+{
+  // Configure WiFiClientSecure to use the AWS IoT device credentials
+  net.setCACert(AWS_CERT_CA);
+  net.setCertificate(AWS_CERT_CRT);
+  net.setPrivateKey(AWS_CERT_PRIVATE);
+
+  // Connect to the MQTT broker on the AWS endpoint we defined earlier
+  client.begin(AWS_IOT_ENDPOINT, 8883, net);
+  client.onMessage(messageHandler);
+  Serial.print("Connecting to AWS IOT");
+
+  while (!client.connect(THINGNAME)) {
+    Serial.print(".");
+    delay(100);
+  }
+
+  if (!client.connected()) {
+    Serial.println("AWS IoT Timeout!");
+    return;
+  }
+  // Subscribe to a topic
+  client.subscribe("control/lamp");
+  // Create a message handler
+
+  Serial.println("AWS IoT Connected!");
+}
+
+void messageHandler(String &topic, String &payload) {
+  Serial.println("receiving MQTT message");
+  Serial.println("incoming: " + topic + " - " + payload);
+  int i = payload.toInt();
+  digitalWrite(IO_RELAY,i);
+}