ESP-WROOM-02ボードでMQTTとMPL3115A2(気圧・高度・気温センサ)を動かす（Arduino版）

2020/7/5:
初版

PlatformIO ESP-WROOM-02 MQTT MPL3115A2

PlatformIO ESP-WROOM-02 MQTT MPL3115A2

概要

以下のESP-WROOM-02ボードでMQTTと以下のMPL3115A2(気圧・高度・気温センサ)を動かす（Arduino版）。 (ホストPCとしてはubuntuを想定している)

ESPr® Developer（ESP-WROOM-02開発ボード）
MPL3115A2 - I2C気圧・高度・気温センサ

PINOUT

部品面から見てボードのUSBコネクタを下にした配置

ESP-WROOM-02(Right)
GND
IO16
TOUT
RESET
IO5
TXD
RXD
IO4
GND
VOUT

ESP-WROOM-02(Left)
3V3
EN
IO1
IO12
IO13
IO15
IO2
IO0
GND
VIN

接続

ESP-WROOM-02	MPL3115A2
IO5	SCL
IO4	SDA
GND	GND
3V3	Vin

platformio.ini

  ; PlatformIO Project Configuration File
  ;
  ;   Build options: build flags, source filter
  ;   Upload options: custom upload port, speed and extra flags
  ;   Library options: dependencies, extra library storages
  ;   Advanced options: extra scripting
  ;
  ; Please visit documentation for the other options and examples
  ; https://docs.platformio.org/page/projectconf.html

  [env:huzzah]
  platform = espressif8266
  #board = huzzah
  board = esp_wroom_02
  framework = arduino
  

外部ライブラリ

以下を実行してライブラリをインストールする：

  # MQTT lib インストール
  pio lib install 617

  # Adafruit MPL3115A2 Lib インストール
  pio lib install 796

  #実際に、これだと、コンパイルがエラーになったので、
  #以下のように直接ライブラリのソースをダウンロードする：

  cd src
  wget https://raw.githubusercontent.com/adafruit/Adafruit_MPL3115A2_Library/master/Adafruit_MPL3115A2.cpp
  wget https://raw.githubusercontent.com/adafruit/Adafruit_MPL3115A2_Library/master/Adafruit_MPL3115A2.h

  

MQTT_MPL3115A2_test

src/MQTT_MPL3115A2_test.ino

  //
  // MPL3115A2 sensor data publisher/subscriber
  //
  // MPL3115A2 Library url:
  // https://github.com/adafruit/Adafruit_MPL3115A2_Library
  // MQTT lib url:
  // https://github.com/256dpi/arduino-mqtt

  #include <Wire.h>
  #include <Adafruit_MPL3115A2.h>
  #include <ESP8266WiFi.h>
  #include <MQTT.h>

  const char ssid[] = "yours_ssid";
  const char pass[] = "yours_passwd";

  Adafruit_MPL3115A2 baro = Adafruit_MPL3115A2();

  WiFiClient net;
  MQTTClient client;

  unsigned long lastMillis = 0;

  void connect() {
    Serial.print("checking wifi...");
    while (WiFi.status() != WL_CONNECTED) {
      Serial.print(".");
      delay(1000);
    }

    Serial.print("\nconnecting...");
    //while (!client.connect("arduino", "try", "try")) { // for "broker.shiftr.io"
    while (!client.connect("", "", "")) { // no username. no passwd (for "mqtt.eclipse.org")
      Serial.print(".");
      delay(1000);
    }

    Serial.println("\nconnected!");

    client.subscribe("topic0");
    // client.unsubscribe("/hello");
  }

  void messageReceived(String &topic, String &payload) {
    Serial.println("incoming: " + topic + " - " + payload);
  }

  void setup() {
    Serial.begin(115200);
    WiFi.begin(ssid, pass);

    // Note: Local domain names (e.g. "Computer.local" on OSX) are not supported by Arduino.
    // You need to set the IP address directly.
    //client.begin("broker.shiftr.io", net); //OK
    client.begin("mqtt.eclipse.org", net); //OK
    //client.begin("test.mosquitto.org", net); //NG?
    client.onMessage(messageReceived);

    connect();
  }

  void loop() {
    char s[100]; // buf for sprintf
    if (! baro.begin()) {
      Serial.println("Couldnt find sensor");
      return;
    }
    float pascals = baro.getPressure();
    Serial.print(pascals/100); Serial.println(" hPa");
    //
    float altm = baro.getAltitude();
    Serial.print(altm); Serial.println(" meters");
    //
    float tempC = baro.getTemperature();

    client.loop();
    delay(10);  // <- fixes some issues with WiFi stability

    if (!client.connected()) {
      connect();
    }

    // publish a message roughly every second.
    if (millis() - lastMillis > 1000) {
      lastMillis = millis();
      //client.publish("topic0", String((int)pascals));
      sprintf(s,"{ \"press\" : %.2f, \"altm\" : %.1f, \"tempC\" : %.1f}", pascals/100, altm, tempC);
      client.publish("topic0", &s[0]);
    }
    delay(2000);
  }
  

以下については、自分の環境に合わせて変更すること：

  const char ssid[] = "yours_ssid";
  const char pass[] = "yours_passwd";
  

以下は利用するMQTTサーバー(broker)に合わせてコメントアウトする：

    //client.begin("broker.shiftr.io", net); //OK
    client.begin("mqtt.eclipse.org", net); //OK
  

書き込み後に「picocom /dev/ttyUSB0 -b115200」で通信ソフトを起動すると以下のような出力が表示される：

  $ picocom /dev/ttyUSB0 -b115200

  Terminal ready

  1002.88 hPa
  86.88 meters
  incoming: topic0 - { "press" : 1002.88, "altm" : 87.000000.1, "tempC" : 28.1}
  1002.86 hPa
  87.00 meters
  incoming: topic0 - { "press" : 1002.88, "altm" : 86.875000.1, "tempC" : 28.1}
  1002.86 hPa
  86.44 meters
  incoming: topic0 - { "press" : 1002.86, "altm" : 87.000000.1, "tempC" : 28.1}
  1002.86 hPa
  86.50 meters
  incoming: topic0 - { "press" : 1002.86, "altm" : 86.437500.1, "tempC" : 28.2}
  1002.87 hPa
  86.94 meters
  incoming: topic0 - { "press" : 1002.86, "altm" : 86.500000.1, "tempC" : 28.2}
  1002.90 hPa
  87.06 meters
  incoming: topic0 - { "press" : 1002.87, "altm" : 86.937500.1, "tempC" : 28.1}
  1002.85 hPa
  86.75 meters
  incoming: topic0 - { "press" : 1002.90, "altm" : 87.062500.1, "tempC" : 28.1}
  1002.89 hPa
  86.56 meters
  incoming: topic0 - { "press" : 1002.85, "altm" : 86.750000.1, "tempC" : 28.2}
  1002.90 hPa
  86.44 meters
  incoming: topic0 - { "press" : 1002.89, "altm" : 86.562500.1, "tempC" : 28.2}
  1002.90 hPa
  86.69 meters
  incoming: topic0 - { "press" : 1002.90, "altm" : 86.437500.1, "tempC" : 28.2}
  1002.96 hPa
  86.44 meters

  ...
  <省略>

  

対向する送受信プログラム

以下をブラウザ(chromeのみ)で動かす：

MQTT_AT_webTestZero.html

  <html>

  <script src="https://unpkg.com/mqtt/dist/mqtt.min.js"></script>
  <body>

  <script>
  //var mqtt_url = 'ws://test.mosquitto.org:8081'
  var mqtt_url = 'ws://mqtt.eclipse.org/mqtt:443'
  //var mqtt_url = 'wss://try:try@broker.shiftr.io'

  document.body.innerHTML = '';
  var consout = 'MQTT over WebSockets Test'+'('+mqtt_url+')<br>'
  document.body.innerHTML = consout;

  //var mqtt = require('mqtt');
  var client = mqtt.connect(mqtt_url);

  // subscribe Topic
  //client.subscribe('hello');
  client.subscribe('topic0');
  //client.subscribe('topic0/sample/hello');
  //client.subscribe('topic0/sample/#');
  // wildcard topic
  //client.subscribe('topic0/#');
  //client.subscribe('#');

  client.on('message', function(topic, payload) {
    console.log([topic, payload].join(': '));
    consout += [topic, payload].join(': ')+'<br>'
    document.body.innerHTML = consout
    // disconnect
    //client.end();
  });

  // publish messages
  client.publish('topic0', 'hello world of MQTT! #1');
  client.publish('topic0', 'hello world of MQTT! #2');
  client.publish('topic0', 'hello world of MQTT! #3');
  client.publish('topic0', 'hello world of MQTT! #4');
  client.publish('topic0', 'hello world of MQTT! #5');

  </script>

  </body>

  </html>
  

デモプログラムを起動後、上の「MQTT_AT_webTestZero.html」をプラウザーで起動すると
以下のweb画面が表示される(例)：

MQTT over WebSockets Test(ws://mqtt.eclipse.org/mqtt:443)
  topic0: hello world of MQTT! #1
  topic0: hello world of MQTT! #2
  topic0: hello world of MQTT! #3
  topic0: hello world of MQTT! #4
  topic0: hello world of MQTT! #5
  topic0: { "press" : 1002.58, "altm" : 88.3, "tempC" : 28.7}
  topic0: { "press" : 1002.58, "altm" : 88.4, "tempC" : 28.7}
  topic0: { "press" : 1002.56, "altm" : 88.1, "tempC" : 28.8}
  topic0: { "press" : 1002.61, "altm" : 88.3, "tempC" : 28.8}
  topic0: { "press" : 1002.59, "altm" : 88.4, "tempC" : 28.7}
  topic0: { "press" : 1002.59, "altm" : 88.4, "tempC" : 28.7}
  topic0: { "press" : 1002.57, "altm" : 88.6, "tempC" : 28.7}
  topic0: { "press" : 1002.59, "altm" : 89.0, "tempC" : 28.7}
  topic0: { "press" : 1002.58, "altm" : 88.2, "tempC" : 28.7}
  topic0: { "press" : 1002.61, "altm" : 88.2, "tempC" : 28.7}
  topic0: { "press" : 1002.60, "altm" : 88.8, "tempC" : 28.7}
  topic0: { "press" : 1002.59, "altm" : 88.6, "tempC" : 28.7}
  topic0: { "press" : 1002.63, "altm" : 88.3, "tempC" : 28.7}
  topic0: { "press" : 1002.59, "altm" : 88.3, "tempC" : 28.8}
  topic0: { "press" : 1002.60, "altm" : 88.3, "tempC" : 28.7}
  ...

  

参考情報

https://docs.shiftr.io/interfaces/mqtt/

The following ports are available on the broker.shiftr.io host:

  MQTT  MQTTS   MQTTWS  MQTTWSS
  1883  8883    80  443

  

MQTT test server @mosquitto.org

https://test.mosquitto.org/
  The server listens on the following ports:
  1883 : MQTT, unencrypted
  8883 : MQTT, encrypted
  8884 : MQTT, encrypted, client certificate required
  8080 : MQTT over WebSockets, unencrypted
  8081 : MQTT over WebSockets, encrypted
  websocketで使用するurlは以下になる：
  'ws://test.mosquitto.org:8081'
  

MQTT test server @eclipse.org

http://mqtt.eclipse.org/
  This is a public test MQTT broker service.
  It currently listens on the following ports:
  1883 : MQTT over unencrypted TCP
  8883 : MQTT over encrypted TCP
  80 : MQTT over unencrypted WebSockets (note: URL must be /mqtt )
  443 : MQTT over encrypted WebSockets (note: URL must be /mqtt )
  websocketで使用するurlは以下になる：
  'ws://mqtt.eclipse.org/mqtt:443'
  

10 Free Public & Private MQTT Brokers(For Testing & Production)

PlatformIO Core (CLI)

以上