I have a project where I have to combine 4 sensors and get data wireless via Bluetooth (HC05). I just want help with combining just 1 sensor sketch and the Bluetooth sketch. I want the data from the temperature sensor to be displayed on my phone.

Temperature sensor code:

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2

OneWire oneWire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);

void setup(void)
  // start serial port
  Serial.println("Dallas Temperature IC Control Library Demo");

  // Start up the library

void loop(void)
  // call sensors.requestTemperatures() to issue a global temperature
  // request to all devices on the bus
  Serial.print(" Requesting temperatures...");

  Serial.print("Temperature is: ");

Bluetooth code:

#include <SoftwareSerial.h>
SoftwareSerial BT(11, 10);
int ledPin = 8;
int state = 0;

void setup()

pinMode(ledPin, OUTPUT);

void loop() {
  if(BT.available() > 0){ 
  state = BT.read();

    if (state == '0'){
      digitalWrite(ledPin, LOW);
      BT.println("LED: OFF");
      state = 0;
    else if (state == '1'){
      digitalWrite(ledPin, HIGH);
      BT.println("LED: ON");;
      state = 0;


Instead of writing it all out, I give some tips:

  • First combine the content of both setup functions. You can remove duplicate lines (e.g. Serial.begin(9600); is needed only once. Keep the order in a logical way.

  • Than combine the content of both loop functions. However, the delay could cause a problem. Replace this by keeping a variable with the current time, and check when it's at least a second ago you checked the temperature sensor, if so, measure the sensor (and update the variable to the current time).

So you get something like:

unsigned long lastSensorMeasurement;

void setup()
   // Combination of both setup functions

   lastSensorMeasurement = millis();

void loop()
   // Process sensor
   if (lastSensorMeasurement + 1000 >= millis())
      // Code for sensor as in loop

   // Process Bluetooth
   // Code for bluetooth as in loop
  • 1
    now() only has a resolution of 1 second. Usually you use millis() for timing, which gives 1/1000 of a second resolution. – Duncan C Mar 6 at 13:27
  • @DuncanC Thanks ... of course I meant that; I updated my answer, thanks for the notification. – Michel Keijzers Mar 6 at 13:33

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