ESP8266でIoT - Adafruit IO偏

　 Adafruit IOでESP8266のWiFiモジュールをIoTデバイスに使用する方法を説明します。

※「ESP8266でIoT - 開発環境のセットアップ」の手順で開発環境をセットアップ済のこととします。

○準備

①「Adafruit IO+Arduino+MQTTでIoT‐センサー・データの収集」の「③Adafruit IOの準備」の手順でアカウントを作成します。

②「Adafruit MQTT Library」(Adafruit_MQTT_Library-master.zip)をダウンロードします。

③Arudino IDEを起動します。

④[スケッチ]→[ライブラリをインクルード]→[.ZIP形式のライブラリをインクルード]を選択します。

⑤ダウンロードしたZIPファイル「Adafruit_MQTT_Library-master.zip」を選択し、[開く]をクリックします。

○プログラム　

・データの送信

　Adafruit IOにデータを送信するプログラムは、次のように書きます。

	#include <ESP8266WiFi.h>
	#include "Adafruit_MQTT.h"
	#include "Adafruit_MQTT_Client.h"
	#define WLAN_SSID "...your SSID..."
	#define WLAN_PASS "...your password..."
	// Adafruit.io Setup
	#define AIO_SERVER "io.adafruit.com"
	#define AIO_SERVERPORT 1883 // use 8883 for SSL
	#define AIO_USERNAME "...your AIO username (see https://accounts.adafruit.com)..."
	#define AIO_KEY "...your AIO key..."
	// Create an ESP8266 WiFiClient class to connect to the MQTT server.
	WiFiClient client;
	// or... use WiFiFlientSecure for SSL
	//WiFiClientSecure client;
	// Store the MQTT server, username, and password in flash memory.
	// This is required for using the Adafruit MQTT library.
	const char MQTT_SERVER[] PROGMEM = AIO_SERVER;
	const char MQTT_USERNAME[] PROGMEM = AIO_USERNAME;
	const char MQTT_PASSWORD[] PROGMEM = AIO_KEY;
	// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
	Adafruit_MQTT_Client mqtt(&client, MQTT_SERVER, AIO_SERVERPORT, MQTT_USERNAME, MQTT_PASSWORD);
	// Setup a feed called 'Welcome Feed' for publishing.
	// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
	const char PHOTOCELL_FEED[] PROGMEM = AIO_USERNAME "/feeds/Welcome Feed";
	Adafruit_MQTT_Publish Analog = Adafruit_MQTT_Publish(&mqtt, PHOTOCELL_FEED);
	void MQTT_connect();
	void setup() {
	Serial.begin(115200);
	delay(10);
	// Connect to WiFi access point.
	Serial.println(); Serial.println();
	Serial.print("Connecting to ");
	Serial.println(WLAN_SSID);
	WiFi.begin(WLAN_SSID, WLAN_PASS);
	while (WiFi.status() != WL_CONNECTED) {
	delay(500);
	Serial.print(".");
	}
	Serial.println();
	Serial.println("WiFi connected");
	Serial.println("IP address: ");
	Serial.println(WiFi.localIP());
	// connect to adafruit io
	MQTT_connect();
	}
	void loop() {
	// ping adafruit io a few times to make sure we remain connected
	if(! mqtt.ping(3)) {
	// reconnect to adafruit io
	if(! mqtt.connected())
	MQTT_connect();
	}
	// Grab the current state of the analog input
	float analog_data = analogRead(A0);
	// Publish data
	if (!Analog.publish(analog_data))
	Serial.println(F("Failed to publish analog data"));
	else
	Serial.println(F("Analog data published!"));
	// Repeat every 10 seconds
	delay(10000);
	}
	// Function to connect and reconnect as necessary to the MQTT server.
	// Should be called in the loop function and it will take care if connecting.
	void MQTT_connect() {
	int8_t ret;
	// Stop if already connected.
	if (mqtt.connected()) {
	return;
	}
	Serial.print("Connecting to MQTT... ");
	uint8_t retries = 3;
	while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
	Serial.println(mqtt.connectErrorString(ret));
	Serial.println("Retrying MQTT connection in 5 seconds...");
	mqtt.disconnect();
	delay(5000); // wait 5 seconds
	retries--;
	if (retries == 0) {
	// basically die and wait for WDT to reset me
	while (1);
	}
	}
	Serial.println("MQTT Connected!");
	}

view raw adafruit_Publish.ino hosted with ❤ by GitHub

・データの取得

　Adafruit IOからデータを取得するプログラムは、次のように書きます。

	#include <ESP8266WiFi.h>
	#include "Adafruit_MQTT.h"
	#include "Adafruit_MQTT_Client.h"
	// LED pin
	const int led_pin = 5;
	#define WLAN_SSID "...your SSID..."
	#define WLAN_PASS "...your password..."
	// Adafruit.io Setup
	#define AIO_SERVER "io.adafruit.com"
	#define AIO_SERVERPORT 1883 // use 8883 for SSL
	#define AIO_USERNAME "...your AIO username (see https://accounts.adafruit.com)..."
	#define AIO_KEY "...your AIO key..."
	// Create an ESP8266 WiFiClient class to connect to the MQTT server.
	WiFiClient client;
	// or... use WiFiFlientSecure for SSL
	//WiFiClientSecure client;
	// Store the MQTT server, username, and password in flash memory.
	// This is required for using the Adafruit MQTT library.
	const char MQTT_SERVER[] PROGMEM = AIO_SERVER;
	const char MQTT_USERNAME[] PROGMEM = AIO_USERNAME;
	const char MQTT_PASSWORD[] PROGMEM = AIO_KEY;
	// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
	Adafruit_MQTT_Client mqtt(&client, MQTT_SERVER, AIO_SERVERPORT, MQTT_USERNAME, MQTT_PASSWORD);
	// Setup a feed called 'LED' for subscribing to changes.
	// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
	const char PHOTOCELL_FEED[] PROGMEM = AIO_USERNAME "/feeds/LED";
	Adafruit_MQTT_Subscribe led = Adafruit_MQTT_Subscribe(&mqtt, PHOTOCELL_FEED);
	void MQTT_connect();
	void setup() {
	// Set lamp pin to output
	pinMode(led_pin, OUTPUT);
	Serial.begin(115200);
	delay(10);
	// Connect to WiFi access point.
	Serial.println(); Serial.println();
	Serial.print("Connecting to ");
	Serial.println(WLAN_SSID);
	WiFi.begin(WLAN_SSID, WLAN_PASS);
	while (WiFi.status() != WL_CONNECTED) {
	delay(500);
	Serial.print(".");
	}
	Serial.println();
	Serial.println("WiFi connected");
	Serial.println("IP address: ");
	Serial.println(WiFi.localIP());
	// listen for events on the led feed
	mqtt.subscribe(&led);
	// connect to adafruit io
	MQTT_connect();
	}
	void loop() {
	Adafruit_MQTT_Subscribe *subscription;
	// ping adafruit io a few times to make sure we remain connected
	if(! mqtt.ping(3)) {
	// reconnect to adafruit io
	if(! mqtt.connected())
	MQTT_connect();
	}
	// this is our 'wait for incoming subscription packets' busy subloop
	while (subscription = mqtt.readSubscription(1000)) {
	// we only care about the led events
	if (subscription == &led) {
	// convert mqtt ascii payload to int
	char *value = (char *)led.lastread;
	Serial.print(F("Received: "));
	Serial.println(value);
	// Apply message to led
	String message = String(value);
	message.trim();
	if (message == "ON") {digitalWrite(led_pin, HIGH);}
	if (message == "OFF") {digitalWrite(led_pin, LOW);}
	}
	}
	}
	// Function to connect and reconnect as necessary to the MQTT server.
	// Should be called in the loop function and it will take care if connecting.
	void MQTT_connect() {
	int8_t ret;
	// Stop if already connected.
	if (mqtt.connected()) {
	return;
	}
	Serial.print("Connecting to MQTT... ");
	uint8_t retries = 3;
	while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
	Serial.println(mqtt.connectErrorString(ret));
	Serial.println("Retrying MQTT connection in 5 seconds...");
	mqtt.disconnect();
	delay(5000); // wait 5 seconds
	retries--;
	if (retries == 0) {
	// basically die and wait for WDT to reset me
	while (1);
	}
	}
	Serial.println("MQTT Connected!");
	}

view raw adafruit_Subscribe.ino hosted with ❤ by GitHub

　LEDを制御するためのフィード、ブロックの方法については、「Adafruit IO+Arduino+MQTTでIoT‐デバイスの制御」の「③Adafruit の準備」を参照してください。

　LEDは、GPIO5に接続します。