# Retrieve Last Data from Antares Server with MQTT Protocol In this project, you will be directed to retrieve data from **Antares IoT Platform** to ESP8266 using WiFi connectivity with MQTT protocol. ## Prerequisites The materials required follow the **General Prerequisites** on the previous page. If you have not prepared the requirements on that page, then you can visit the following page. {% content-ref url="/pages/FfvYH4773vShlmvxo6Gj" %} [General Prerequisites ESP8266 Wi-Fi](/en/code-and-library-examples/esp8266-wi-fi/general-prerequisites-esp8266-wi-fi.md) {% endcontent-ref %} The additional materials specific to this project are as follows. 1. Antares ESP MQTT Library. This documentation uses the **Antares ESP MQTT library version 1.0.** {% hint style="info" %} If you have not installed **Antares ESP MQTT version 1.0**, you can follow these steps. [Antares Wi-Fi MQTT](/en/getting-started/arduino-library-installation/antares-wi-fi-mqtt.md) {% endhint %} ## Follow These Steps ### **1.** Launch the Arduino IDE application ### **2.** Opening Sample Programme {% hint style="info" %} You can open the programme code in the Arduino IDE via **File > Example > Antares ESP HTTP > GetLatestData.** {% endhint %} Below is the GetLatestData sample programme code. ```cpp /* This code will fetch the latest data from your antares project device. Your Antares project device must have a structure like this: (Note that nesting the JSON object can only be done up to 2 levels using this library) { "temperature": some-integer, "humidity": some-integer, "wind_speed": some-float, "rain_level": some-float, "location" : { "latitude": "static-string", "longitude": "static-string" } } For more information please visit https://antares.id/id/docs.html */ #include // Include the AntaresESP32HTTP library #define ACCESSKEY "your-access-key" // Replace with your Antares account access key #define WIFISSID "your-wifi-ssid" // Replace with your Wi-Fi SSID #define PASSWORD "your-wifi-password" // Replace with your Wi-Fi password #define projectName "your-project-name" // Antares project name #define deviceName "your-project-name" // Name of the device AntaresESPHTTP antares(ACCESSKEY); // Initialize AntaresESP32HTTP with the access key void setup() { Serial.begin(115200); // Initialize serial communication antares.setDebug(true); // Enable Antares library debug mode antares.wifiConnection(WIFISSID, PASSWORD); // Connect to WiFi using provided SSID and password } void loop() { // Get the latest data from your Antares device antares.get(projectName, deviceName); // Check if we're actually getting data if (antares.getSuccess()) { int temp = antares.getInt("temperature"); int hum = antares.getInt("humidity"); float windsp = antares.getFloat("wind_speed"); float rainlv = antares.getFloat("rain_level"); String lat = antares.getString("location", "latitude"); String lon = antares.getString("location", "longitude"); Serial.println("Temperature: " + String(temp)); Serial.println("Humidity: " + String(hum)); Serial.println("Wind speed: " + String(windsp)); Serial.println("Rain level: " + String(rainlv)); Serial.println("Latitude: " + lat); Serial.println("Longitude: " + lon); } delay(5000); } ``` ### **3.** Set WiFi Credential and Antares Credential in Program Code Change the HTTP Protocol parameters in the following variables **\*ACCESSKEY, \*WIFISSID, \*PASSWORD, \*projectName,** and **\*deviceName**. Adjust to the parameters in the Antares console. ```arduino #define ACCESSKEY "your-access-key" // Replace with your Antares account access key #define WIFISSID "your-wifi-ssid" // Replace with your Wi-Fi SSID #define PASSWORD "your-wifi-password" // Replace with your Wi-Fi password #define projectName "your-project-name" // Antares project name #define deviceName "your-project-name" // Name of the device ``` {% hint style="info" %} The **\*Access key** parameter is obtained from your Antares account page. {% endhint %}

Access Key Location on Antares Account Page

{% hint style="info" %} The **WIFISSID** parameter is obtained from the name of the **Wifi / Hotspot** that is currently being used by you. for example in the image below. {% endhint %}

The WiFi SSID being used.

{% hint style="info" %} The **\*PASSWORD** parameter is obtained from the **WiFi password** you are currently using. {% endhint %} {% hint style="info" %} The parameters **\*projectName** and **\*deviceName** are obtained from the **Application Name** and **Device Name** that have been created in the Antares account. {% endhint %}

Application Name Display

Device Name Display

### **4. Compile and Upload Program** Connect the **ESP8266 WEMOS D1R2** with your computer and make sure the **Communication Port** is read. {% hint style="info" %} On Windows operating systems, checking can be done via **Device Manager**. If your **ESP8266 WEMOS D1R2** is read, the **USB-Serial CH340** appears with the port adjusting the port availability (in this case it reads **COM4**). {% endhint %}

Device Manager image on Windows.

Set up the **ESP8266 WEMOS D1R2** board by clicking **Tools > Board > esp8266** in the Arduino IDE, then make sure the one used is **LOLIN (WEMOS) D1 R2 & mini**. Select the port according to the communication port that is read (in this case COM4). The result will look like the following picture.

Image of Tools Menu on Arduino IDE

After all the setup is complete, upload the programme by pressing the arrow icon as shown below. Wait for the compile and upload process to finish.

Gambar Icon Verify dan Upload pada Arduino IDE.

{% hint style="info" %} **The Tick icon** on the Arduino IDE is just the verify process. Usually used to **Compile** the programme to find out whether there are errors or not. \ **The Arrow icon** on the Arduino IDE is the verify and upload process. Usually used to **Compile** the programme as well as Flash the programme to the target board. {% endhint %} If the programme upload is successful, it will look like the following image.

Arduino IDE page image after successful upload.

After uploading the programme, you can view the **serial monitor** to debug the programme. The **serial monitor** icon is shown in the following image.

Image of the Serial Monitor Icon in the Arduino IDE.

Set the **serial baud rate** to 115200 and select BothNL & CR. The result will look like the following image. {% hint style="danger" %} Make sure the **serial baud rate** matches the value defined in the programme code. If the **serial baud rate** is not the same between the **programme code** and the **serial monitor**, the ASCII characters will not be read properly. {% endhint %}

Serial Monitor Image

### **5.** Check Data in Serial Monitor After uploading the programme successfully, then open the Serial Monitor page and see if the data has been successfully retrieved.

Serial Monitor Page Image when the data is successfully retrieved.

{% hint style="info" %} Data retrieved from the **Antares IOT Platform** is taken using the **ESP8266** Board with the HTTP protocol in the form of temperature, humidity, wind\_level, rain\_level, and location variables containing latitude and longitude. {% endhint %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.antares.id/en/code-and-library-examples/esp8266-wi-fi/esp8266-wi-fi-mqtt-protocol/retrieve-last-data-from-antares-server-with-mqtt-protocol.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.