Displaying data received by radio module on Blynk

TreeBoy · January 28, 2025, 6:50pm

I’m creating a project on blynk. It’s a communication system where I’m using the follwing:

2 arduino uno
2 NRF24L01 2.4GHz radio modules for communication between the arduinos
1 Grove SW-420 vibration sensor

One arduino (transmitting) has vibration sensor and one nrf module, and the other (receiving) has another nrf module and an LED. I’ve established communication between the two arduinos and when the vibration sensor senses vibration, it transmitts the intensity with some other data to the second arduino through the nrf transceiver. And this data is displayed on the serial monitor of the receiver module and the LED on pin2 blinks if vibration is sensed. Here is the ARDUINO IDE sketches of the Transmitter and Receiver that I wrote and work perfectly fine:

Transmitter:

#include "RF24.h"
#include "printf.h"
int EP = 2;
byte addresses[][6] = {"0"};


/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(7, 8);



void setup() {
  pinMode(EP, INPUT); //set EP input for measurment
  Serial.begin(115200);
  delay(1000);
  radio.begin();  
  radio.setChannel(115); 
  radio.setPALevel(RF24_PA_LOW);
  radio.setDataRate( RF24_250KBPS ) ; 
  radio.openWritingPipe( addresses[0]);
  delay(1000);
  Serial.println("----------------------Sender / Transmitter------------------------");
}

void loop() {
  long measurement = TP_init();
  delay(10);
  Serial.print("measurment = ");
  Serial.println(measurement);
    if (measurement > 100) 
    {
      delay(200);
      // Send a message to rf95_server
      char data1[20] = {0};
      char data2[40]={0};
      char data3[200]={0};
      char data4[200]={0};
      snprintf(data1,20,"%d",measurement);
      snprintf(data2,40,"RTO No.: AS012021");
      snprintf(data3,200,"CUI:HyndaiElantra.5560@gmail.com");
      snprintf(data4,200,"Password: 55605560");
      radio.write(&data1, sizeof(data1)); 
      radio.write(&data2, sizeof(data2)); 
      radio.write(&data3, sizeof(data3)); 
      radio.write(&data4, sizeof(data4));       
      delay(6000);
   
      //radio.waitPacketSent();
    }
    // Now wait for a reply
    uint8_t buf[32];
    uint8_t len = sizeof(buf);

    if (radio.available()) {
      while (radio.available()) radio.read(buf, len);
      Serial.print("got reply: ");
      Serial.println((char*)buf);
    } else {
    digitalWrite(8, LOW); // Assuming 'ss' is pin 8
    }
}  

long TP_init() {
  delay(10);
  long measurement = pulseIn (EP, HIGH); //waits for the pin to get HIGH and returns measurement
  return measurement;
}

Receiver:

#include "RF24.h"
#include "printf.h"

/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(7, 8);


byte addresses[][6] = {"0"};

int ledPin = 2;
int buzzer = 3;


void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buzzer, OUTPUT);
  Serial.begin(115200);
  delay(1000);
  radio.begin();  
  radio.setChannel(115); 
  radio.setPALevel(RF24_PA_LOW);
  radio.setDataRate( RF24_250KBPS ) ; 
  radio.openReadingPipe(1,addresses[0]);
  radio.startListening();
  Serial.println("   ---------------Assam (North-Eastern zone)--------------- \n ---------------Guwahati - Pole #1 (Khanapara)---------------"); 
}

void loop() {
  Serial.print("measurement = 0\n");
  if ( radio.available()) 
  {
    delay(200);
    // Should be a message for us now   
    char buf1[20];
    uint8_t len1 = sizeof(buf1);
    char buf2[40];
    uint8_t len2 = sizeof(buf2);
    char buf3[200];
    uint8_t len3 = sizeof(buf3);
    char buf4[200];
    uint8_t len4 = sizeof(buf4);
    while (radio.available())
    {
      radio.read( &buf1, len1 );
      radio.read( &buf2, len2 );
      radio.read( &buf3, len3 );
      radio.read( &buf4, len4 );
      Serial.print("GOT VIBRATION: measurement= ");
        Serial.println((char*)buf1);
        Serial.println((char*)buf2);
        Serial.println((char*)buf3);
        Serial.println((char*)buf4);
       
        digitalWrite(ledPin, HIGH);
        tone(buzzer, 1200); // Send 1KHz sound signal...
        delay(250);        // ...for 1 sec
        digitalWrite(ledPin, LOW);
        noTone(buzzer);     // Stop sound...
        delay(250);        // ...for 1sec
          
    // Send a reply
        uint8_t data[] = "Thanks for the Data";
        radio.stopListening();
        radio.write(data, sizeof(data));
        radio.startListening();
        Serial.println("Sent a reply");

        digitalWrite(ledPin, LOW);
        digitalWrite(buzzer, LOW);
    }
  }
  delay(6000);

}

Now, actually I want to take vibration measurement data received by receiver arduino in variable buf1 and display that in blynk app. And also glow an LED on the app as and when a vibration is recorded. I’ve already checked my device with the app with an example and my device is getting online.
Till now, this is the code which I’ve written but neither LED is blinking nor Label is displaying measurement:

#define BLYNK_TEMPLATE_NAME         "Quickstart Template"
#define BLYNK_AUTH_TOKEN            "                                "
#include <SPI.h>
#include "RF24.h"
#include "printf.h"

/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(7, 8);


byte addresses[][6] = {"0"};

int ledPin = 2;
int buzzer = 3;



#define BLYNK_PRINT SwSerial


#include <SoftwareSerial.h>
SoftwareSerial SwSerial(10, 11); // RX, TX

#include <BlynkSimpleStream.h>
WidgetLED led1(V1);


BlynkTimer timer;

void purpose()
{
  Serial.print("measurement = 0\n");
  if ( radio.available()) 
  {
    delay(200);
    // Should be a message for us now   
    char buf1[20];
    uint8_t len1 = sizeof(buf1);
    char buf2[40];
    uint8_t len2 = sizeof(buf2);
    char buf3[200];
    uint8_t len3 = sizeof(buf3);
    char buf4[200];
    uint8_t len4 = sizeof(buf4);
    while (radio.available())
    {
      radio.read( &buf1, len1 );
      radio.read( &buf2, len2 );
      radio.read( &buf3, len3 );
      radio.read( &buf4, len4 );
      Serial.print("GOT VIBRATION: measurement= ");
        Serial.println((char*)buf1);
        Serial.println((char*)buf2);
        Serial.println((char*)buf3);
        Serial.println((char*)buf4);
        int mes=atoi(buf1);
        Blynk.virtualWrite(V0,mes);
        timer.setTimeout(0, []() { led1.on(); });
        timer.setTimeout(250L, []() { led1.off(); });
        digitalWrite(ledPin, HIGH);
        tone(buzzer, 1200); // Send 1KHz sound signal...
        delay(250);        // ...for 1 sec
        digitalWrite(ledPin, LOW);
        noTone(buzzer);     // Stop sound...
        delay(250);        // ...for 1sec        
        
    // Send a reply
        uint8_t data[] = "Thanks for the Data";
        radio.stopListening();
        radio.write(data, sizeof(data));
        radio.startListening();
        Serial.println("Sent a reply");

        digitalWrite(ledPin, LOW);
        digitalWrite(buzzer, LOW);
    }
  }
  delay(6000); 
}

void setup()
{
  pinMode(ledPin, OUTPUT);
  pinMode(buzzer, OUTPUT);
  // Debug console
  SwSerial.begin(115200);

  // Blynk will work through Serial
  // Do not read or write this serial manually in your sketch
  Serial.begin(9600);
  Blynk.begin(Serial, BLYNK_AUTH_TOKEN);
    // Setup a function to be called every second

  
  radio.begin();  
  radio.setChannel(115); 
  radio.setPALevel(RF24_PA_LOW);
  radio.setDataRate( RF24_250KBPS ) ; 
  radio.openReadingPipe(1,addresses[0]);
  radio.startListening();
  timer.setInterval(1000L, purpose);
}

void loop()
{
  Blynk.run();
  timer.run();  
  // You can inject your own code or combine it with other sketches.
  // Check other examples on how to communicate with Blynk. Remember
  // to avoid delay() function!
}

Someone kindly help me

OS: Windows 11
• Smartphone OS : Android 14
• Blynk Library 1.3.2

PeteKnight · January 28, 2025, 7:45pm

First of all, you won’t get good results from Blynk when you use delays in your code.
You’ve added a BlynkTimer, which is good, but instead of having that timer call your function every 6 seconds, you’re calling it every 1 seconds then using a 6 second delay to control the timing.

Without knowing which widgets you’ve set-up in Blynk, which datastreams they are connected to, and how those datastreams are configured it’s difficult to understand what you’re doing in your code from a Blynk point of view.

If you’re doing debugging, it’s always good to use serial prints of the actual variables that you’re sending to Blynk before you send them.

Here, you have no idea what the actual value of the mes variable is…

Pete.

TreeBoy · January 29, 2025, 4:26am

Here’s my blynk web interface:

I’ve got two widgets: one Label(V1) and one LED(V0). I’m not debugging btw. Those serial prints were already part of my earlier code. Please help me out.

You’re right, I’ve no idea of the actual value of “mes”. But I know that it’s the vibration measurement of sensor which the transmitter is sending. but I want what’s stored by buf1 to be displayed in label.
first of all, why is the ledwidget not blinking? As soon as connect to the blynk server, my physical LED and buzzer are perfectly running whenever vibration is received.

PeteKnight · January 29, 2025, 7:31am

So add a serial print statement to your code to print its value so you can visualise it.

Your first priority needs to be to restructure your code to remove the delays.

You’ve also provided information about your web dashboard, but not about how your datastreams are configured.

Pete

TreeBoy · January 29, 2025, 4:23pm

But if I’ll print serially, then I’ll have to open serial monitor to see if it’s getting printed or not. And for checking that then I can’t connect my device to Blynk server. Then, I guess this line won’t get executed:

Then my function “purpose” won’t be called and hence the value of variable mes won’t be printed if I try to print it serially.

Am I right?

PeteKnight · January 29, 2025, 4:59pm

I’d forgotten that you’re using the weird USB serial connection.

However, you already have serial print segments in your code, which need to be changed if you are using the USB connection method.
You’ve created a SoftwareSerial port, called SwSerial, using pins 10 and 11.
You’re initialising this at a baud rate that is far too fast for the SoftwareSerial library running on the Uno,…

Your Serial.print statements need to be changed to SwSerial.print, and you need to connect an FTDI adapter to pins 10 and 11 to allow you to view your serial output.

Is there any reason why you’re using this antiquated hardware and weird USB connection, rather than something like an ESP32 and a WiFi connection?

Pete.

TreeBoy · January 29, 2025, 5:25pm

May seem bit weird and outdated in modern times but my project can’t rely on wifi (short range) so mostly guided media is needed.

If that is too fast should I change it to 4800?

Will do that and get back.

I currently can’t buy an adapter.

I’m using radio because I need to show possibility of this transmission over a wide area using long-range radio and without internet.

What about making led and label widget live?

PeteKnight · January 29, 2025, 5:37pm

How does your PC connect to the internet?

Probably 9600 would be better. You’ll need to set your serial monitor to the same baud rate.

In that case you won’t be able to debug your code and resolve your problems.

I was referring to the device that connects to Blynk. Without internet you can’t use Blynk anyway.

Can’t comment on that until you:

Share datastream setup
Restructure your code to remove delays
Change your code to stop doing serial prints
Have some method of debugging your code via a serial monitor (FTDI needed)

Pete.

TreeBoy · January 30, 2025, 7:22pm

Through wifi, but since radio modules would be far away with microcontrollers, so wifi can’t be there. Moreover USB is easy to setup and I have been doing this by USB.

For now, I have converted every serial.println line and made it Swserial.print.

Here, it’s not available. I’ve less time so if some alternate option could work…?

That’s perfectly fine The receiving device is using BLYNK to show possibility of IOT integration.
BTW, 2 years back for the same project I used blynk with the transmitting device and directly took sensor reading in LABEL and got LED blinked. But now the target is different and twisted. Should’ve shared this earlier.

Here it is:

done

For that should I use timer.setTimeout(millis, myFunction) method?

PeteKnight · January 30, 2025, 7:36pm

Your reciever device can’t be far from your PC, otherwise the USB connection to the PC.

Believe me, USB is NOT easier to set-up compared to WiFi. if your receiver device was an ESP32 you would have been able to debug your issues already.

Hopefully not, your SoftwareSerial port is called SwSerial not Swserial.

Not really.

I’ve already said…

I can’t help further if you insist on using this hardware without an FTDI, or swapping your receiver to an ESP32 or ESP8266.

Pete.

TreeBoy · January 31, 2025, 12:18pm

Yes, I’m aware of that. Have written SwSerial only

BTW, I’ve done it. Successful after lots of tinkering.