ESP8266에서 잠시 실행하면 JsonData 크기가 0이 됩니다. (JsonData size becomes zero after awhile of running in ESP8266)

문제 설명

ESP8266에서 잠시 실행하면 JsonData 크기가 0이 됩니다. (JsonData size becomes zero after awhile of running in ESP8266)

데이터를 읽어 Json Object로 파싱하고 MQTT를 통해 rpi로 객체를 전송하는 nodemcu 1.0(ESP‑12E Module) 관련 프로젝트를 구축 중입니다. 내 문제는 실행 1~2분 후에 Json 개체가 손상되고 jsonData.size()가 json의 예상 크기에서 0으로 출력된다는 것입니다.

제 코드는 다음과 같습니다.

#include <ArduinoJson.h>
#include "Adafruit_MQTT.h" 
#include "Adafruit_MQTT_Client.h" 
#include <Wire.h>
#include <MCP3008.h>

//define pin connections
#define CS_PIN D8
#define CLOCK_PIN D5
#define MOSI_PIN D7
#define MISO_PIN D6

// WiFi
// Make sure to update this for your own WiFi network!
const char* ssid = "NameOfNetwork";
const char* wifi_password = "walakokabalohaha";

// MQTT
// Make sure to update this for your own MQTT Broker!
const char* mqtt_server = "192.168.4.1";
const char* mqtt_topic = "test";
const char* mqtt_username = "username";
const char* mqtt_password = "Kakkakka123";
// The client id identifies the ESP8266 device. Think of it a bit like a hostname (Or just a name, like Greg).
const char* clientID = "Client ID";

MCP3008 adc(CLOCK_PIN, MOSI_PIN, MISO_PIN, CS_PIN);

// Initialise the WiFi and MQTT Client objects
WiFiClient client;
Adafruit_MQTT_Client mqtt(&client, mqtt_server, 1883, mqtt_username, mqtt_password);
Adafruit_MQTT_Publish sensorPub = Adafruit_MQTT_Publish(&mqtt, "test");
//Adafruit_MQTT_Subscribe sensorSub = Adafruit_MQTT_Subscribe(&mqtt, "sensor");
DynamicJsonBuffer jsonBuffer;

void setup(void)
{
Serial.begin(115200);
WiFi.mode(WIFI_STA);
setupWifi();
// Connect to MQTT Broker
MQTT_connect();
delay(500);
}

void loop(void)
{
  transmitJsonData(getSensorData());

delay(300);
}
void setupWifi(){
  Serial.print("Connecting to ");
  Serial.println(ssid);

  // Connect to the WiFi
  WiFi.begin(ssid, wifi_password);

  // Wait until the connection has been confirmed before continuing
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  // Debugging ‑ Output the IP Address of the ESP8266
  Serial.println("WiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

}

void MQTT_connect(){
  uint8_t retries = 3; 
  int8_t ret; 
  while((ret = mqtt.connect()) !=0 ) {
    Serial.println("Connection to MQTT Broker failed...");
    mqtt.disconnect();
    delay(5000);
    retries‑‑;
    if(retries == 0){
      ESP.wdtDisable();
      while(1);
    }
  }
  Serial.println("Connected to MQTT Broker!");
}

JsonObject& getSensorData(){
    float index_data = adc.readADC(0);
    float ring_data = adc.readADC(1);
    float middle_data = adc.readADC(2);
    float point_data = adc.readADC(3);
    float thumb_data = adc.readADC(4);

//    StaticJsonBuffer<300> jsonBuffer;
    JsonObject& sensorData = jsonBuffer.createObject();
    sensorData["index_finger"] = String (index_data);
    sensorData["ring_finger"] = String (ring_data);
    sensorData["middle_finger"] = String (middle_data);
    sensorData["point_finger"] = String (point_data);
    sensorData["thumb_finger"] = String(thumb_data);

    Serial.println(sensorData["index_finger"].as<char*>());
    Serial.println(sensorData["ring_finger"].as<char*>());
    Serial.println(sensorData["middle_finger"].as<char*>());
    Serial.println(sensorData["point_finger"].as<char*>());
    Serial.println(sensorData["thumb_finger"].as<char*>());
    Serial.println(sensorData.size());

    return sensorData;
}

void transmitJsonData(JsonObject& data){
//    Serial.println("Transmitting data...");

    String sPayload = "";
    data.printTo(sPayload);
    char* cPayload = &sPayload[0u];

    if(!sensorPub.publish(cPayload))
        Serial.println("Transmit failed!");
    else
        Serial.println("Transmit successful.");
}

저는 nodemcu 빌드에 처음이고 문제의 원인을 모릅니다.

참조 솔루션

방법 1:

clearing jsonBuffer by calling jsonBuffer.clear() fixed the problem as what Mr. Maxim suggested.

(by Klien Menard、Klien Menard)

참조 문서

1. JsonData size becomes zero after awhile of running in ESP8266 (CC BY‑SA 2.5/3.0/4.0)