In this tutorial we will write a simple code that will read temperature from BME280 sensor, and if temperature is higher than 30°C it will send a SMS to the receivers number.
platformio.ini
As usual we will use PlatformIO for this embedded project, and our platformio.ini should look like this:
[env:release]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
lib_deps =
iotaap/IoTaaP OS@^5.2.2
adafruit/Adafruit BME280 Library@^2.2.2
board_build.partitions = partitions/default_fat.csv
Headers and declaration
#include <IoTaaP_OS.h>
#include <Arduino.h>
#include <ArduinoJson.h>
#include "Adafruit_BME280.h"
#define TOKEN "<iotaap-link-secret>" // IoTaaP Link Secret
Adafruit_BME280 bme; // I2C
IoTaaP_OS iotaapOs("3.2.8"); // Defining Firmware version
We have to include our headers as usual, since Adafruit_BME280.h requires some functions from Arduino.h, we have to include it also. Additionally we have to declare our bme sensor and create iotaapOs object.
Also we have to define TOKEN, so please do not forget to replace <iotaap-link-secret> with your IoTaaP Link Secret.
setup() function
void setup()
{
// BME280 related stuff
unsigned status;
status = bme.begin(0x76);
if (!status)
{
Serial.println("Could not find a valid BME280 sensor, check wiring, address, sensor ID!");
while (1)
delay(10);
}
iotaapOs.start(); // Start IoTaaP OS
iotaapOs.startWifi(); // Connect to WiFi
iotaapOs.startMqtt(callback); // Connect to MQTT broker
}
In the first part of the function, we are checking if BME280 is available and working, this is a good practice in this example, to eliminate further issues if sensor is not working properly.
Next, we have to call iotaapOs.start() function to start our IoTaaP OS services, this is followed by iotaapOs.startWifi() to connect to start WiFi service and iotaapOs.startMqtt() to connect to the IoTaaP network, and define MQTT callback function.
callback() function
void callback(char *topic, byte *message, unsigned int length)
{
Serial.println("-------#-----#-----#----------");
Serial.println("Received data on the topic:");
Serial.println(topic); // Print topic
Serial.println("Data:");
for (int i = 0; i < length; i++) // Print message
{
Serial.print((char)message[i]);
}
Serial.println();
Serial.println("------#------#------#---------");
}
This is basic MQTT callback function that will print received data and topic to our Serial Terminal, it is used to check the status of the service.
loop() function
void loop()
{
// Fetch measurements from BME280 sensor
float temperatureC = bme.readTemperature();
// If temperature is higher than 30°C, send SMS using IoTaaP SMS service, and subscribe to callback topic
if (temperatureC > 30)
{
char message[50];
sprintf(message, "Current temperature is: %.1f°C", temperatureC);
iotaapOs.smsServiceSend(TOKEN, "+38599", message, "/pgiIzx7n/smsservice/response");
}
delay(5000);
}
This function is repeated constantly, and it will read the temperature from our BME280 sensor and store it in temperatureC variable. Next, we will check if temperature is higher than 30°C and if it is we will first craft our SMS message using sprintf function.
Finally, we will use iotaapOs.smsServiceSend() function to send the SMS using IoTaaP SMS service.
Do not forget to update receivers phone number (it must contain country code). Also your must have permission to listen on your callback topic.
Complete code
Below you can find the complete code for this example.
#include <IoTaaP_OS.h>
#include <Arduino.h>
#include <ArduinoJson.h>
#include "Adafruit_BME280.h"
#define TOKEN "<iotaap-link-secret>" // IoTaaP Link Secret
Adafruit_BME280 bme; // I2C
IoTaaP_OS iotaapOs("3.2.8"); // Defining Firmware version
// IoTaaP Network (MQTT) callback function
void callback(char *topic, byte *message, unsigned int length)
{
Serial.println("-------#-----#-----#----------");
Serial.println("Received data on the topic:");
Serial.println(topic); // Print topic
Serial.println("Data:");
for (int i = 0; i < length; i++) // Print message
{
Serial.print((char)message[i]);
}
Serial.println();
Serial.println("------#------#------#---------");
}
void setup()
{
// BME280 related stuff
unsigned status;
status = bme.begin(0x76);
if (!status)
{
Serial.println("Could not find a valid BME280 sensor, check wiring, address, sensor ID!");
while (1)
delay(10);
}
iotaapOs.start(); // Start IoTaaP OS
iotaapOs.startWifi(); // Connect to WiFi
iotaapOs.startMqtt(callback); // Connect to MQTT broker
}
void loop()
{
// Fetch measurements from BME280 sensor
float temperatureC = bme.readTemperature();
// If temperature is higher than 30°C, send SMS using IoTaaP SMS service, and subscribe to callback topic
if (temperatureC > 30)
{
char message[50];
sprintf(message, "Current temperature is: %.1f°C", temperatureC);
iotaapOs.smsServiceSend(TOKEN, "+38599", message, "/pgiIzx7n/smsservice/response");
}
delay(5000);
}
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