In this project, you will use the Antares Workshop Shield on the Lynx-32 Development Board module. In this Antares Shield Workshop, there are temperature, humidity (DHT11), relay, LED, and push button sensors. You will monitor the temperature and humidity with a specified interval period. The data sent by the sensors can be monitored through the Antares console and displayed on the OLED. You can also send messages in the form of string data displayed on the OLED display. This data transmission process uses POSTMAN software to send data to the Antares IoT Platform.
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.
The additional materials specific to this project are as follows.
You can open the programme code in the Arduino IDE via File > Examples > Antares ESP HTTP > Lynx32-Simple-Project > POST_DATA_GET_DATA_OLED.
Here is the programme code of the POST_DATA_GET_DATA_OLED. example.
#include <AntaresESPHTTP.h> // Include the AntaresESP32HTTP library
#include <Adafruit_SSD1306.h> // Include the Adafruit SSD1306 library
#include "DHT.h" // Include the DHT sensor library
#define DHTPIN 14 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // Type of DHT sensor (DHT11 in this case)
#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" // Antares project name
#define deviceNameSensor "YOUR-DEVICE-NAME-1" // Name of the device sending sensor data
#define deviceNamePostman "YOUR-DEVICE-NAME-2" // Name of the device receiving data
AntaresESPHTTP antares(ACCESSKEY); // Initialize AntaresESP32HTTP with the access key
DHT dht(DHTPIN, DHTTYPE); // Initialize DHT sensor object
#define SCREEN_WIDTH 128 // OLED screen width in pixels
#define SCREEN_HEIGHT 64 // OLED screen height in pixels
#define OLED_RESET -1 // Reset pin for the OLED (not used in this case)
const unsigned long interval = 5000; // Interval to send sensor data (5 seconds)
const unsigned long interval2 = 10000; // Interval to get data from Antares (10 seconds)
unsigned long previousMillis = 0; // Store the last time sensor data was sent
unsigned long previousMillis2 = 0; // Store the last time data was received from Antares
String testData; // String to hold received data from Antares
String lastData=""; // String to store last received data
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); // Initialize OLED display object
bool showSensorData = true; // Boolean to control display of sensor data
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
dht.begin(); // Initialize the DHT sensor
if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Initialize the OLED display
Serial.println(F("SSD1306 allocation failed"));
for (;;)
;
}
display.clearDisplay(); // Clear the OLED display buffer
display.display(); // Display the cleared buffer
}
void loop() {
if (millis() - previousMillis > interval) { // Check if it's time to send sensor data
previousMillis = millis(); // Update the last sent time
float hum = dht.readHumidity(); // Read humidity from the DHT sensor
float temp = dht.readTemperature(); // Read temperature from the DHT sensor
if (isnan(hum) || isnan(temp)) {
Serial.println("Failed to read DHT sensor!"); // Print an error message if sensor reading fails
return;
}
antares.add("temperature", temp); // Add temperature data to the Antares payload
antares.add("humidity", hum); // Add humidity data to the Antares payload
antares.send(projectName, deviceNameSensor); // Send sensor data to Antares
display.clearDisplay(); // Clear the OLED display buffer
display.setTextSize(1); // Set text size on the display
display.setTextColor(SSD1306_WHITE); // Set text color to white
display.setCursor(0, 0); // Set cursor position on the display
display.println("Temp: " + String(temp) + " *C"); // Display temperature
display.println("Humidity: " + String(hum) + " %"); // Display humidity
display.display(); // Display the updated buffer on the OLED
}
if (millis() - previousMillis2 > interval2) { // Check if it's time to get data from Antares
previousMillis2 = millis(); // Update the last received time
antares.get(projectName, deviceNamePostman); // Get data from Antares
if (antares.getSuccess()) { // Check if data retrieval was successful
testData = antares.getString("Test Data"); // Get the "Test Data" field from the response
if(lastData != testData) // Check if the received data is different from the last one
{
lastData = testData; // Update the last received data
Serial.println("Received Data: " + testData); // Print received data to the serial monitor
display.clearDisplay(); // Clear the OLED display buffer
display.setTextSize(1); // Set text size on the display
display.setTextColor(SSD1306_WHITE); // Set text color to white
display.setCursor(0, 0); // Set cursor position on the display
display.println("Received:"); // Display "Received:"
display.println(testData); // Display the received data
display.display(); // Display the updated buffer on the OLED
delay(2000); // Display received data for 2 seconds
}
}
}
}
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.
#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" // Antares project name
#define deviceNameSensor "YOUR-DEVICE-NAME-1" // Name of the device sending sensor data
#define deviceNamePostman "YOUR-DEVICE-NAME-2" // Name of the device receiving data
The *Access key parameter is obtained from your Antares account page.
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.
The *PASSWORD parameter is obtained from the WiFi 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.
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).
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.
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
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.
After uploading the programme, you can view the serial monitor to debug the programme. The serial monitor icon is shown in the following image.
Set the serial baud rate to 115200 and select BothNL & CR. The result will look like the following image.
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.
5. Setup POSTMAN Software
In this step you need POSTMAN software, you can input the end-point, request header and request body first by following the following format.
In the POSTMAN software, select the Body tab then select raw and enter the payload according to the request body you want to use as shown below.
Customise the contents of the "con" field according to the "key" and "value" you want to send.
6. Customise the contents of the "con" field according to the "key" and "value" you want to send.
After the POSTMAN software setup is complete, it's time to send the POST command. The "Test Data" field is filled with the string "Halloo Test" as the message to be sent via HTTP protocol to the Antares server.
