How to Send Multiple Sensors Data wirelessly using Arduino & 433Mhz RF Rx Tx

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Description:

How to Send Multiple Sensors Data wirelessly using Arduino & 433Mhz RF Rx Tx- In this project, you will learn how to connect multiple sensors with Arduino and send Sensors data wirelessly using 433Mhz Radio Frequency Rx and Tx modules. Rx Tx stands for Receiver and transmitter. In this project we will connect 6 Flex Sensors with the Arduino and send their values wirelessly. This project can be easily modified, different types of multiple sensors can be interfaced with the Arduino Uno, Arduino Mega, or Arduino Nano, etc, this way advanced level projects can be designed. As this project is based on the 433Mhz short-range radio frequency communication, so this can be ideal for control a robot with multiple functions, Home or office automation, etc.

You will learn a lot of new things in this project, apart from sending multiple sensors values, you will also learn how to make a complete message consisting of sensor values, and then how to split that message and access each sensor value individually. This splitting of a string message will really help you in advanced level projects.

If you have never used the 433Mhz Radio frequency Rx Tx module then I highly recommend you should read my getting started article on the Arduino 433Mhz RF transmitter and Receiver which explains everything you need to know.

I have also another version of the multiple sensors monitoring using 15Km Lora Transceiver Modules. If you are interested in long range two way communication then read my article on Multiple sensors monitoring using Lora.

There are so many other projects in which I have used the 433Mhz Radio Frequency Rx Tx modules. You can find these projects in the related projects section given below.

I this article, I will cover

Transmitter Circuit diagram
Receiver circuit diagram
Arduino Transmitter side programming
Arduino receiver side programming

Without any further delay, let’s get started!!!

Amazon links:

Arduino Nano USB-C Type (Recommended)

433 MHz Transmitter and Receiver Modules:

Flex sensor:

Arduino Uno

*Disclosure: These are affiliate links. As an Amazon Associate I earn from qualifying purchases.

Multiple Sensors and 433Mhz RF Tx with Arduino Circuit Diagram:

As you can see the circuit diagram is very simple. This is the transmitter side circuit diagram. But before, I am going to explain the circuit diagram, first let me explain what is a Flex Sensor.

A flex sensor which is also known as the bend sensor is a sensor that measures the amount of bending or deflection.

The Flex Sensor or Bend Sensor is usually stuck to the surface whose bend is to be monitored, as the surface is bent the resistance of the Flex sensor or Bend sensor varies. So we can say that the resistance of the Flex Sensor or Bend Sensor is directly proportional to the amount of Bend.

The Flex sensors are also used for the precise angle measures, the flex sensor just like an ordinary resistor, the only difference is the in the construction, so we can call this Flex Sensor or Bend Sensor as the Flexible Potentiometer.

The Flex Sensor or Bend sensor as you can see in the Picture has two contacts or legs due to which it can be easily used with the Breadboard, but Personally, I recommend soldering jumper wires with these two contacts is the better option, as it can be then easily interfaced with the Arduino Uno or Mega.

It’s Working Principle as I said is just like the normal variable resistor or Potentiometer, with the only difference; that is the flex sensor resistance changes with the bend while the variable resistor or potentiometer resistor, resistance changes as we rotate the knob. There are also some other types of the Flex sensor or Bend sensor, but the one you can see on the screen is the Conductive Ink-based Flex Sensor.

So, now that you know about the Flex sensor, now let me explain the circuit diagram. In the circuit diagram above you can see I have used 6 Flex sensors, as I said earlier a Flex sensor is just like a variable resistor. You can see clearly in the circuit diagram, with every Flex sensor I have used a 10K ohm resistor in series. The Flex sensor and the 10k resistor makes the voltage divider circuit. When the Flex Sensor is bend the resistor is changed, so the voltage is changed and that’s why a wire from the middle of the voltage divider (flex sensor and 10k ohm resistor) is connected with Arduino’s analog pin. The same is done for all the sensors. All the 6 Flex sensors are connected with the Arduino’s analog pins A0, A1, … A5. It’s totally up to you, you can use potentiometers if you don’t have the Flex sensors, or you can use other analog sensors, even you can use some digital sensors, if you know how to use them.

A 433Mhz Rf Tx module data pin is connected with the Arduino’s pin number 12, while the power pins are connected with the Arduino’s 5V and ground pins.

Multiple Sensors and 433Mhz RF Rx with Arduino Circuit Diagram:

The receiver side circuit diagram is extremely simple. This is a very basic circuit diagram. We are not controlling anything at this point. Our only aim is to receive the data coming from multiple sensors wirelessly and then split this data and display it on the Serial monitor. If you want you can add some devices to control like, motors, lights, etc.

Before you start the programming, first of all, make sure that you download the VirtualWire library. This is based on two programs, one program is written for the transmitter side which sends the multiple sensors values, while the other program is written for the receiver side which receives the multiple sensors data and display it on the Serial Monitor.

Multiple Sensors Arduino Transmitter Side Arduino Programming:

// Transmitter programming
#include <VirtualWire.h>
const int transmit_pin = 12;

int flexs1 = A0; // flex sensor is connected with pin A0 of the arduino
int flexdata1 = 0; 

int flexs2 = A1; 
int flexdata2 = 0;

 int flexs3 = A2; 
 int flexdata3 = 0; 

  int flexs4 = A3; 
 int flexdata4 = 0; 

   int flexs5 = A4; 
 int flexdata5 = 0;

    int flexs6 = A5; 
 int flexdata6 = 0; 

 String str;
 char cstr[100];

String message = "";
 

unsigned int mlength; // message length 
 
void setup()
{
      // Initialise the IO and ISR
    vw_set_tx_pin(transmit_pin);
     vw_setup(2000);       // Bits per sec
  Serial.begin(9600);
  
    pinMode(flexs1, INPUT); 
    pinMode(flexs2, INPUT);
    pinMode(flexs3, INPUT);
    pinMode(flexs4, INPUT);
    pinMode(flexs5, INPUT);
    pinMode(flexs6, INPUT);
}

void loop()
{

 flexdata1 = analogRead(flexs1);
 flexdata2 = analogRead(flexs2);
  flexdata3 = analogRead(flexs3);
   flexdata4 = analogRead(flexs4); 
    flexdata5 = analogRead(flexs5);
     flexdata6 = analogRead(flexs6);

// each group can have maximum of 4 sensors and a group number
SendData(flexdata1,flexdata2,flexdata3,flexdata4,1); // in group 1 we have 4 sensors
delay(500);

SendData(flexdata5,flexdata6,0,0,2); // in group 2 we have 2 sensors 
delay(500);               
}

// this function takes 5 arguments as the input
// the sensors and the sensors group number. 
// let's say we are using multiple sensors, the sensors 
//can be divided into groups. 
void SendData( int sensor1,int sensor2,int sensor3,int sensor4, int sgroup)
{

message = message + sensor1 +"," + sensor2 + "," + sensor3 +"," + sensor4 + "," + sgroup;
mlength = message.length(); // find the number of characters in a message.
  str = message;
  str.toCharArray(cstr,100);
  vw_send((uint8_t *)cstr, mlength); // 
  vw_wait_tx(); // Wait until the whole message is gone
  str = "";
  message = ""; 

}

// Transmitter programming

#include <VirtualWire.h>

const int transmit_pin = 12;

int flexs1 = A0; // flex sensor is connected with pin A0 of the arduino

int flexdata1 = 0;

int flexs2 = A1;

int flexdata2 = 0;

int flexs3 = A2;

int flexdata3 = 0;

int flexs4 = A3;

int flexdata4 = 0;

int flexs5 = A4;

int flexdata5 = 0;

int flexs6 = A5;

int flexdata6 = 0;

String str;

char cstr[100];

String message = "";

unsigned int mlength; // message length

void setup()

{

// Initialise the IO and ISR

vw_set_tx_pin(transmit_pin);

vw_setup(2000); // Bits per sec

Serial.begin(9600);

pinMode(flexs1, INPUT);

pinMode(flexs2, INPUT);

pinMode(flexs3, INPUT);

pinMode(flexs4, INPUT);

pinMode(flexs5, INPUT);

pinMode(flexs6, INPUT);

}

void loop()

{

flexdata1 = analogRead(flexs1);

flexdata2 = analogRead(flexs2);

flexdata3 = analogRead(flexs3);

flexdata4 = analogRead(flexs4);

flexdata5 = analogRead(flexs5);

flexdata6 = analogRead(flexs6);

// each group can have maximum of 4 sensors and a group number

SendData(flexdata1,flexdata2,flexdata3,flexdata4,1); // in group 1 we have 4 sensors

delay(500);

SendData(flexdata5,flexdata6,0,0,2); // in group 2 we have 2 sensors

delay(500);

}

// this function takes 5 arguments as the input

// the sensors and the sensors group number.

// let's say we are using multiple sensors, the sensors

//can be divided into groups.

void SendData( int sensor1,int sensor2,int sensor3,int sensor4, int sgroup)

{

message = message + sensor1 +"," + sensor2 + "," + sensor3 +"," + sensor4 + "," + sgroup;

mlength = message.length(); // find the number of characters in a message.

str = message;

str.toCharArray(cstr,100);

vw_send((uint8_t *)cstr, mlength); //

vw_wait_tx(); // Wait until the whole message is gone

str = "";

message = "";

}

Multiple Sensors Receiver Side Arduino Programming:

// receiver Programming

#include <VirtualWire.h>


const int receive_pin = 11;

String message; 
String myString;

// sensors
int sensor1; 
int sensor2;
int sensor3;
int sensor4;
int sensor5;
int sensor6;
int sensor7;
int sensor8;

int data1; 
int data2; 
int data3; 
int data4; 

int group; 


void setup()
{
    delay(1000);
    Serial.begin(9600); // Debugging only
    Serial.println("setup");

    // Initialise the IO and ISR

    vw_set_rx_pin(receive_pin);

    vw_set_ptt_inverted(true); // Required for DR3100
    vw_setup(2000);  // Bits per sec

    vw_rx_start();       // Start the receiver PLL running

}

void loop()
{
    uint8_t buf[VW_MAX_MESSAGE_LEN];
    uint8_t buflen = VW_MAX_MESSAGE_LEN;

    if (vw_get_message(buf, &buflen)) // Non-blocking
    {
    int i;

     
    // Message with a good checksum received, dump it.
    //Serial.print("Got: ");
    
    for (i = 0; i < buflen; i++)
    {
        char c = (buf[i]);
            message = message + c ; // make a message from the received characters         
    }
  myString = message; 
    Serial.println(message);

// each time receive data from only 4 sensors and a group number
String l = getValue(myString, ',', 0); // sensor1
String m = getValue(myString, ',', 1); // sensor2
String n = getValue(myString, ',', 2); // sensor3
String o = getValue(myString, ',', 3); // sensor4
String p = getValue(myString, ',', 4); // group number

data1 = l.toInt();
data2 = m.toInt();
data3 = n.toInt();
data4 = o.toInt();
group = p.toInt();

// we check wether we receive data from sensors in group1 or group2 
if ( group == 1 )
{
  sensor1 = data1; 
  sensor2 = data2; 
  sensor3 = data3; 
  sensor4 = data4;
}

if ( group == 2 )
{
  sensor5 = data1; 
  sensor6 = data2; 
  sensor7 = data3; 
  sensor8 = data4;
}

Serial.println("*********Group1************"); 
Serial.println(sensor1);  
Serial.println(sensor2);
Serial.println(sensor3);
Serial.println(sensor4);

Serial.println("*********Group2************"); 
Serial.println(sensor5);  
Serial.println(sensor6);
Serial.println(sensor7);
Serial.println(sensor8);

     message = "";
    }
    

}


String getValue(String data, char separator, int index)
{
    int found = 0;
    int strIndex[] = { 0, -1 };
    int maxIndex = data.length() - 1;

    for (int i = 0; i <= maxIndex && found <= index; i++) {
        if (data.charAt(i) == separator || i == maxIndex) {
            found++;
            strIndex[0] = strIndex[1] + 1;
            strIndex[1] = (i == maxIndex) ? i+1 : i;
        }
    }
    return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
}

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// receiver Programming

#include <VirtualWire.h>

const int receive_pin = 11;

String message;

String myString;

// sensors

int sensor1;

int sensor2;

int sensor3;

int sensor4;

int sensor5;

int sensor6;

int sensor7;

int sensor8;

int data1;

int data2;

int data3;

int data4;

int group;

void setup()

{

delay(1000);

Serial.begin(9600); // Debugging only

Serial.println("setup");

// Initialise the IO and ISR

vw_set_rx_pin(receive_pin);

vw_set_ptt_inverted(true); // Required for DR3100

vw_setup(2000); // Bits per sec

vw_rx_start(); // Start the receiver PLL running

}

void loop()

{

uint8_t buf[VW_MAX_MESSAGE_LEN];

uint8_t buflen = VW_MAX_MESSAGE_LEN;

if (vw_get_message(buf, &buflen)) // Non-blocking

{

int i;

// Message with a good checksum received, dump it.

//Serial.print("Got: ");

for (i = 0; i < buflen; i++)

{

char c = (buf[i]);

message = message + c ; // make a message from the received characters

}

myString = message;

Serial.println(message);

// each time receive data from only 4 sensors and a group number

String l = getValue(myString, ',', 0); // sensor1

String m = getValue(myString, ',', 1); // sensor2

String n = getValue(myString, ',', 2); // sensor3

String o = getValue(myString, ',', 3); // sensor4

String p = getValue(myString, ',', 4); // group number

data1 = l.toInt();

data2 = m.toInt();

data3 = n.toInt();

data4 = o.toInt();

group = p.toInt();

// we check wether we receive data from sensors in group1 or group2

if ( group == 1 )

{

sensor1 = data1;

sensor2 = data2;

sensor3 = data3;

sensor4 = data4;

}

if ( group == 2 )

{

sensor5 = data1;

sensor6 = data2;

sensor7 = data3;

sensor8 = data4;

}

Serial.println("*********Group1************");

Serial.println(sensor1);

Serial.println(sensor2);

Serial.println(sensor3);

Serial.println(sensor4);

Serial.println("*********Group2************");

Serial.println(sensor5);

Serial.println(sensor6);

Serial.println(sensor7);

Serial.println(sensor8);

message = "";

}

String getValue(String data, char separator, int index)

{

int found = 0;

int strIndex[] = { 0, -1 };

int maxIndex = data.length() - 1;

for (int i = 0; i <= maxIndex && found <= index; i++) {

if (data.charAt(i) == separator || i == maxIndex) {

found++;

strIndex[0] = strIndex[1] + 1;

strIndex[1] = (i == maxIndex) ? i+1 : i;

}

return found > index ? data.substring(strIndex[0], strIndex[1]) : "";

}

I hope you have learned a lot you new things. If you have any questions regarding this project or any other project, let me know in a comment. Don’t forget to subscribe my Website and YouTube channel “Electronic Clinic”.