WioLTE: MQTT で Subscribe したデータを表示する

フォルダー構造

$ tree mqtt_subscribe/
mqtt_subscribe/
├── mqtt_subscribe.ino
├── setupLTE.ino
└── setup_mqtt.ino

mqtt_subscribe.ino

// ---------------------------------------------------------------
/*
    mqtt_subscribe.ino

                    Aug/20/2021
*/
// ---------------------------------------------------------------
#include <WioLTEforArduino.h>
#include <WioLTEClient.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <stdio.h>

#define MQTT_SERVER_HOST  "example.com"
#define MQTT_SERVER_PORT  (1883)

#define ID                "WioLTE"
#define OUT_TOPIC         "sample/imageTopic"
#define IN_TOPIC          "sample/imageTopic"

WioLTE Wio;
WioLTEClient WioClient(&Wio);
PubSubClient MqttClient;

int icount = 0;
// ---------------------------------------------------------------
void callback(char* topic, byte* payload, unsigned int length)
{
    SerialUSB.println("*** callback ***");
    payload[length] = '\0';
    String msg = String((char*) payload);
    SerialUSB.println(msg);
}

// ---------------------------------------------------------------
void setup()
{
    setupLTE();

    setup_mqtt_proc();

    SerialUSB.println("*** Setup completed *** Aug/20/2021 PM 20:20 ***");
}

// ---------------------------------------------------------------
void loop()
{
    DynamicJsonDocument doc(512);
    char data_json[128];

    if ((icount % 1000) == 0)
        {
        doc["icount"] = icount;
        doc["uptime"] = millis() / 1000;
        serializeJson(doc, data_json);

        SerialUSB.println(data_json);
        }

    MqttClient.loop();

    icount++;
}

// ---------------------------------------------------------------

setupLTE.ino はこちら
UDP で温度と湿度を Harvest に送る

setup_mqtt.ino はこちら
ブラウザーから MQTT Publish でブザーを鳴らす

シリアルモニタの表示

20:15:22.403 -> *** Connecting to "soracom.io" ***
20:15:23.529 -> *** SetupLTE completed ***
20:15:23.529 -> *** end *** seupLTE ***
20:15:23.529 -> ### Connecting to MQTT server "example.com"
20:15:23.761 -> *** subscribe ***
20:15:23.761 -> *** Setup completed *** Aug/20/2021 PM 20:20 ***
20:15:23.761 -> {"icount":0,"uptime":14}
20:15:24.192 -> *** callback ***
20:15:24.192 -> {"buzzer":"off"}
20:15:27.180 -> {"icount":1000,"uptime":17}
20:15:30.266 -> {"icount":2000,"uptime":20}
20:15:32.389 -> *** callback ***
20:15:32.389 -> {"buzzer":"on"}
20:15:33.649 -> {"icount":3000,"uptime":24}
20:15:36.767 -> {"icount":4000,"uptime":27}
20:15:37.496 -> *** callback ***
20:15:37.496 -> {"buzzer":"off"}
20:15:39.884 -> *** callback ***
20:15:39.884 -> {"buzzer":"on"}
20:15:40.482 -> {"icount":5000,"uptime":31}
20:15:43.599 -> {"icount":6000,"uptime":34}
20:15:46.684 -> {"icount":7000,"uptime":37}
20:15:49.769 -> {"icount":8000,"uptime":40}
20:15:52.887 -> {"icount":9000,"uptime":43}
20:15:56.072 -> {"icount":10000,"uptime":46}