Retrieve the Last Data from Antares Server with HTTP Protocol

In this project, you will be directed to retrieve data from Antares IoT Platform to Lynx-32 Development Board using Wi-Fi connectivity with HTTP 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.

General Prerequisites ESP32 Wi-Fi

The additional materials specific to this project are as follows.

1. Antares ESP HTTP Library. This documentation uses the Antares ESP HTTP library version 1.4.0.

If you have not installed Antares ESP HTTP 1.4.0, please follow these steps.

Follow These Steps

1. Launch the Arduino IDE application

2. Opening Sample Programme

You can open the programme code in the Arduino IDE via File > Examples > Antares ESP HTTP > AntaresGetLatestData.

The following is the AntaresGetLatestData example programme code.

/*
  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 <AntaresESPHTTP.h>

#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-APPLICATION-NAME"   // Replace with the Antares application name that was created
#define deviceName "YOUR-DEVICE-NAME"     // Replace with the Antares device name that was created

AntaresESPHTTP antares(ACCESSKEY);

void setup() {
    Serial.begin(115200);
    antares.setDebug(true);
    antares.wifiConnection(WIFISSID, 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 HTTP Parameters in Programme Code

Change the HTTP Protocol parameters in the following variables *ACCESSKEY, *WIFISSID, *PASSWORD, *projectName, and *deviceName. Adjust to the parameters in the Antares console.

#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-APPLICATION-NAME"   // Replace with the Antares application name that was created
#define deviceName "YOUR-DEVICE-NAME"     // Replace with the Antares device name that was created

The *Access key parameter is obtained from your Antares account page.

Access Key Location on Antares Account Page

The WIFISSID parameter is obtained from the Wi-Fi/Hotspot name that will be used by the Lynx-32 Development Board. An example is shown below.

WIFISSID

The *PASSWORD parameter is obtained from the Wi-Fi password you are currently using.

The parameters *projectName and *deviceName are obtained from the Application Name and Device Name that have been created in the Antares account.

Application Name Display

Device Name Display

4. Compile and Upload Program

Connect the Lynx-32 with your computer and make sure the Communication Port is read.

On Windows operating systems the check can be done via Device Manager. If your Lynx-32 is read then the USB-Serial CH340 appears with the port adjusting the port availability (in this case it reads COM4).

Device Manager Display

Set up the ESP32 board by clicking Tools > Board > esp32 in the Arduino IDE, then make sure the ESP32 Dev Module is used. Select the port according to the communication port that is read (in this case COM4). The result will look like the following image.

Display of Board Specifications and Ports Used

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

Compile Icon for Tick and Upload Icon for Arrow

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.

If the programme upload is successful, it will look like the following image.

Arduino IDE page image after successful upload.

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.

Serial Monitor Image

5. Check Data in Antares

After uploading the programme successfully, then open the device antares page and see if the data has been successfully sent.