Parsing JSON in Arduino

Parsing JSON in Arduino involves handling JSON data received from a server or another device and extracting relevant information from it. To achieve this, you can use Arduino libraries like ArduinoJson, which simplifies the parsing process. Here’s a basic guide on how to parse JSON data using the ArduinoJson library:

Step-by-Step Guide:

1. Install the ArduinoJson Library

Open the Arduino IDE, go to Sketch -> Include Library -> Manage Libraries.... In the Library Manager, search for “ArduinoJson” and click the Install button to install the library.

2. Parse JSON Data

Here’s a sample code demonstrating how to parse JSON data received as a string:

#include <ArduinoJson.h> // Include the ArduinoJson library

void setup() {
  Serial.begin(9600); // Start serial communication for debugging
  DynamicJsonDocument doc(1024); // Create a JSON document (adjust the size as needed)
  
  // Sample JSON string received (replace it with your actual JSON string)
  const char* json = "{\"sensor\":\"temperature\",\"value\":25.5}";

  // Deserialize the JSON data
  DeserializationError error = deserializeJson(doc, json);
  
  // Check for parsing errors
  if (error) {
    Serial.print("Deserialization failed: ");
    Serial.println(error.c_str());
    return;
  }
  
  // Extract values from JSON
  const char* sensorType = doc["sensor"];
  float sensorValue = doc["value"];

  // Display parsed data
  Serial.print("Sensor Type: ");
  Serial.println(sensorType);
  Serial.print("Sensor Value: ");
  Serial.println(sensorValue);
}

void loop() {
  // Nothing in the loop for this example
}

Explanation:

• #include <ArduinoJson.h>: Includes the ArduinoJson library.
• Serial.begin(9600);: Starts serial communication for displaying output (adjust baud rate as needed).
• DynamicJsonDocument doc(1024);: Creates a JSON document of size 1024 bytes (adjust as per your JSON data size).
• const char* json = "{\"sensor\":\"temperature\",\"value\":25.5}";: Simulates receiving JSON data as a string.
• deserializeJson(doc, json);: Parses the JSON string into the JSON document doc.
• doc["sensor"]: Extracts the value associated with the “sensor” key.
• doc["value"]: Extracts the value associated with the “value” key.

Conclusion:

Parsing JSON in Arduino using the ArduinoJson library allows you to extract and utilize data from JSON-formatted strings. This process is essential for working with IoT devices, APIs, or any communication that involves JSON data transmission. By leveraging the ArduinoJson library, handling JSON data becomes more manageable, facilitating efficient data processing and interaction within Arduino projects.