BIOS0031 TMP36 to MQTT sketch

BIOS0031tmp36MQTT.ino

/*
  WiFi TMP to MQTT

 Circuit:
 * LED attached to pin 9
 * TMP36 attached to pin A0

 created Feb 2023
 by Duncan Wilson
 */
#include <SPI.h>
#include <WiFi101.h>
#include <ArduinoMqttClient.h>

// Wifi and MQTT
#include "arduino_secrets.h" 
/*
**** please enter your sensitive data in the Secret tab/arduino_secrets.h
**** using format below

#define SECRET_SSID "ssid name"
#define SECRET_PASS "ssid password"
#define SECRET_MQTTUSER "user name - eg student"
#define SECRET_MQTTPASS "password";
 */

const char* ssid     = SECRET_SSID;
const char* pass     = SECRET_PASS;
const char* mqttuser = SECRET_MQTTUSER;
const char* mqttpass = SECRET_MQTTPASS;

WiFiClient wifiClient;
MqttClient mqttClient(wifiClient);

const char* broker = "mqtt.cetools.org";
int        port     = 1884;
const char topicTMP36[]  = "student/BIOS0031/ucjtdjw/temperature";

int status = WL_IDLE_STATUS;
WiFiServer server(80);

//set interval for sending messages (milliseconds)
const long interval = 8000;
unsigned long previousMillis = 0;

#define debugSerial Serial
//TMP36 Pin Variables
int sensorPin = A0; //the analog pin the TMP36's Vout (sense)
float temperatureC = 0;

void setup() {
  debugSerial.begin(9600);      // initialize serial communication
  // Wait a maximum of 10s for Serial Monitor
  while (!debugSerial && millis() < 10000)
    ;
  pinMode(9, OUTPUT);      // set the LED pin mode
  
  setupWiFi();
  setupMQTT();

}

void loop() {
  // call poll() regularly to allow the library to send MQTT keep alives which
  // avoids being disconnected by the broker
  mqttClient.poll();

  if (!mqttClient.connected()) {
    setupMQTT();
  }

  unsigned long currentMillis = millis();
	
  if (currentMillis - previousMillis >= interval) {
    // save the last time a message was sent
    previousMillis = currentMillis;

    getTempC();
    debugSerial.print(temperatureC); debugSerial.println(" degrees C");

    // send message, the Print interface can be used to set the message contents
    mqttClient.beginMessage(topicTMP36);
    mqttClient.print(temperatureC);
    mqttClient.endMessage();

  }

}

void getTempC(){
  //getting the voltage reading from the temperature sensor
  int reading = analogRead(sensorPin);  

  // converting that reading to voltage, for 3.3v arduino use 3.3
  float voltage = reading * 3.3;
  voltage /= 1024.0; 

  // now print out the temperature
  temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset
                                                //to degrees ((voltage - 500mV) times 100)

}

void setupWiFi() {
  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present");
    while (true);       // don't continue
  }

  // attempt to connect to WiFi network:
  while ( status != WL_CONNECTED) {
    Serial.print("Attempting to connect to Network named: ");
    Serial.println(ssid);                   // print the network name (SSID);

    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);
    // wait 10 seconds for connection:
    delay(10000);
  }
  server.begin();                           // start the web server on port 80
  printWiFiStatus();                        // you're connected now, so print out the status

}

void setupMQTT() {

  // You can provide a unique client ID, if not set the library uses Arduino-millis()
  // Each client must have a unique client ID
  //mqttClient.setId("ucjtdjwBIOS");

  // You can provide a username and password for authentication
  mqttClient.setUsernamePassword(mqttuser, mqttpass);

  // Loop until we're reconnected
  while (!mqttClient.connected()) {    // while not (!) connected....
    Serial.print("Attempting to connect to the MQTT broker: ");
    Serial.println(broker);
    
    // Attempt to connect
    if (mqttClient.connect(broker, port)) {
      Serial.println("You're connected to the MQTT broker!");
    } else {
      Serial.print("MQTT connection failed! Error code = ");
      Serial.println(mqttClient.connectError());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }

}

void printWiFiStatus() {
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");

}