nRF24L01 not working, Now sending ...failed

Using Arduino Networking, Protocols, and Devices
1

Hello everyone,

I have some problems with nRF24L01 module(with antenna), I have bought two recently and I tried to connect them and transmit and receive some data but I wasn't able to do that. I'm using standard RF24 library. When I tried example "GettingStarted" I got that in response:

RF24/examples/GettingStarted
*** PRESS 'T' to begin transmitting to the other node
*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK
Now sending
failed
Failed, response timed out.
Now sending
failed
Failed, response timed out.
Now sending
failed
Failed, response timed out.

When I chose to receive I got nothing(nothing happened, just blank serial monitor).

The same thing happens for both modules connected to different arduinos. I did some research but none of the methods I found worked(adding capacitors, changing wires, or even adding radio.setAutoAck(false); into code). Below I have my connection checks(code found on some website)

Module 1:

FIRST WITH THE DEFAULT ADDRESSES after power on
Note that RF24 does NOT reset when Arduino resets - only when power is removed
If the numbers are mostly 0x00 or 0xff it means that the Arduino is not
communicating with the nRF24

STATUS = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0
RX_ADDR_P0-1 = 0x65646f4e31 0x4141417852
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR = 0x65646f4e31
RX_PW_P0-6 = 0x20 0x20 0x00 0x00 0x00 0x00
EN_AA = 0x3f
EN_RXADDR = 0x02
RF_CH = 0x4c
RF_SETUP = 0x03
CONFIG = 0x0e
DYNPD/FEATURE = 0x00 0x00
Data Rate = 1MBPS
Model = nRF24L01+
CRC Length = 16 bits
PA Power = PA_LOW

AND NOW WITH ADDRESS AAAxR 0x41 41 41 78 52 ON P1
and 250KBPS data rate

STATUS = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0
RX_ADDR_P0-1 = 0x65646f4e31 0x4141417852
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR = 0x65646f4e31
RX_PW_P0-6 = 0x20 0x20 0x00 0x00 0x00 0x00
EN_AA = 0x3f
EN_RXADDR = 0x02
RF_CH = 0x4c
RF_SETUP = 0x23
CONFIG = 0x0e
DYNPD/FEATURE = 0x00 0x00
Data Rate = 250KBPS
Model = nRF24L01+
CRC Length = 16 bits
PA Power = PA_LOW

Module 2:

FIRST WITH THE DEFAULT ADDRESSES after power on
Note that RF24 does NOT reset when Arduino resets - only when power is removed
If the numbers are mostly 0x00 or 0xff it means that the Arduino is not
communicating with the nRF24

STATUS = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0
RX_ADDR_P0-1 = 0xe7e7e7e7e7 0xc2c2c2c2c2
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR = 0xe7e7e7e7e7
RX_PW_P0-6 = 0x00 0x00 0x00 0x00 0x00 0x00
EN_AA = 0x3f
EN_RXADDR = 0x03
RF_CH = 0x4c
RF_SETUP = 0x07
CONFIG = 0x0e
DYNPD/FEATURE = 0x00 0x00
Data Rate = 1MBPS
Model = nRF24L01+
CRC Length = 16 bits
PA Power = PA_MAX

AND NOW WITH ADDRESS AAAxR 0x41 41 41 78 52 ON P1
and 250KBPS data rate

STATUS = 0x0e RX_DR=0 TX_DS=0 MAX_RT=0 RX_P_NO=7 TX_FULL=0
RX_ADDR_P0-1 = 0xe7e7e7e7e7 0x4141417852
RX_ADDR_P2-5 = 0xc3 0xc4 0xc5 0xc6
TX_ADDR = 0xe7e7e7e7e7
RX_PW_P0-6 = 0x00 0x20 0x00 0x00 0x00 0x00
EN_AA = 0x3f
EN_RXADDR = 0x03
RF_CH = 0x4c
RF_SETUP = 0x27
CONFIG = 0x0e
DYNPD/FEATURE = 0x00 0x00
Data Rate = 250KBPS
Model = nRF24L01+
CRC Length = 16 bits
PA Power = PA_MAX

From what I can gather, it doesn't look like it's something wrong with those modules.
One thing I noticed was that when I disconnected the CSN pin I was getting some values transmitted:

*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK
Now sending
failed
Sent 3287208, Got response 0, Round-trip delay 101584 microseconds
Now sending
Sent 4390232, Got response 0, Round-trip delay 29324 microseconds
Now sending
Sent 5420960, Got response 0, Round-trip delay 24708 microseconds
Now sending
Sent 6447064, Got response 0, Round-trip delay 21316 microseconds

What am I doing wrong? Can anyone help?

Thanks in advance.

2

Please post the two programs that YOU have uploaded to your Arduinos and please also post a sample of the output from both.

The Connection Test program in my Tutorial does not test the wireless part of the nRF24

...R
Simple nRF24L01+ Tutorial

3

Hi,

Thank you for your response. Here's the GettingStarted porgram:

/*

  • Getting Started example sketch for nRF24L01+ radios
  • This is a very basic example of how to send data from one node to another
  • Updated: Dec 2014 by TMRh20
    */

#include <SPI.h>
#include "RF24.h"

/****************** User Config ************************/
/ Set this radio as radio number 0 or 1 ***/
bool radioNumber = 0;

/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 /
RF24 radio(9,10);
/*********************************************************/

byte addresses[][6] = {"1Node","2Node"};

// Used to control whether this node is sending or receiving
bool role = 0;

void setup() {
Serial.begin(9600);
Serial.println(F("RF24/examples/GettingStarted"));
Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));

radio.begin();

// Set the PA Level low to prevent power supply related issues since this is a
// getting_started sketch, and the likelihood of close proximity of the devices. RF24_PA_MAX is default.
radio.setPALevel(RF24_PA_LOW);

// Open a writing and reading pipe on each radio, with opposite addresses
if(radioNumber){
radio.openWritingPipe(addresses[1]);
radio.openReadingPipe(1,addresses[0]);
}else{
radio.openWritingPipe(addresses[0]);
radio.openReadingPipe(1,addresses[1]);
}

// Start the radio listening for data
radio.startListening();
}

void loop() {

/****************** Ping Out Role ***************************/
if (role == 1) {

radio.stopListening(); // First, stop listening so we can talk.

Serial.println(F("Now sending"));

unsigned long start_time = micros(); // Take the time, and send it. This will block until complete
if (!radio.write( &start_time, sizeof(unsigned long) )){
Serial.println(F("failed"));
}

radio.startListening(); // Now, continue listening

unsigned long started_waiting_at = micros(); // Set up a timeout period, get the current microseconds
boolean timeout = false; // Set up a variable to indicate if a response was received or not

while ( ! radio.available() ){ // While nothing is received
if (micros() - started_waiting_at > 200000 ){ // If waited longer than 200ms, indicate timeout and exit while loop
timeout = true;
break;
}
}

if ( timeout ){ // Describe the results
Serial.println(F("Failed, response timed out."));
}else{
unsigned long got_time; // Grab the response, compare, and send to debugging spew
radio.read( &got_time, sizeof(unsigned long) );
unsigned long end_time = micros();

// Spew it
Serial.print(F("Sent "));
Serial.print(start_time);
Serial.print(F(", Got response "));
Serial.print(got_time);
Serial.print(F(", Round-trip delay "));
Serial.print(end_time-start_time);
Serial.println(F(" microseconds"));
}

// Try again 1s later
delay(1000);
}

/****************** Pong Back Role ***************************/

if ( role == 0 )
{
unsigned long got_time;

if( radio.available()){
// Variable for the received timestamp
while (radio.available()) { // While there is data ready
radio.read( &got_time, sizeof(unsigned long) ); // Get the payload
}

radio.stopListening(); // First, stop listening so we can talk
radio.write( &got_time, sizeof(unsigned long) ); // Send the final one back.
radio.startListening(); // Now, resume listening so we catch the next packets.
Serial.print(F("Sent response "));
Serial.println(got_time);
}
}

/****************** Change Roles via Serial Commands ***************************/

if ( Serial.available() )
{
char c = toupper(Serial.read());
if ( c == 'T' && role == 0 ){
Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK"));
role = 1; // Become the primary transmitter (ping out)

}else
if ( c == 'R' && role == 1 ){
Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK"));
role = 0; // Become the primary receiver (pong back)
radio.startListening();

}
}

} // Loop

I just changed the baud frequency and CE & CSN pins, and here connection check program:

#include <RF24.h>
#include <SPI.h>
#include <nRF24L01.h>
#include <printf.h>

#define CE_PIN 9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
bool newData = false;

void setup() {
Serial.begin(9600);
printf_begin();

Serial.println("CheckConnection Starting");
Serial.println();
Serial.println("FIRST WITH THE DEFAULT ADDRESSES after power on");
Serial.println(" Note that RF24 does NOT reset when Arduino resets - only when power is removed");
Serial.println(" If the numbers are mostly 0x00 or 0xff it means that the Arduino is not");
Serial.println(" communicating with the nRF24");
Serial.println();
radio.begin();
radio.printDetails();
Serial.println();
Serial.println();
Serial.println("AND NOW WITH ADDRESS AAAxR 0x41 41 41 78 52 ON P1");
Serial.println(" and 250KBPS data rate");
Serial.println();
radio.openReadingPipe(1, thisSlaveAddress);
radio.setDataRate( RF24_250KBPS );
radio.printDetails();
Serial.println();
Serial.println();
}

void loop() {

}

I think it's the same as posted.

The connection check samples I have already posted and here are Getting Started samples:

Module 1:

*** PRESS 'T' to begin transmitting to the other node
*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK
Now sending
failed
Failed, response timed out.
Now sending
failed
Failed, response timed out.
*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK

Module 2(Looks the same):

RF24/examples/GettingStarted
*** PRESS 'T' to begin transmitting to the other node
*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK
Now sending
failed
Failed, response timed out.
Now sending
failed
Failed, response timed out.
*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK

I also posted sample of module 1 when I disconnect CSE, Here's module 2:

*** PRESS 'T' to begin transmitting to the other node
Sent response 0
*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK
Now sending
failed
Sent 3399468, Got response 0, Round-trip delay 95488 microseconds
Now sending
failed
Sent 4500240, Got response 0, Round-trip delay 14192 microseconds
Now sending

I don't really know what is wrong here, anyway thank you for your help.

4

Try the examples in my Tutorial - they are as simple as I could make them and they have worked for other Forum members. If you get stuck it will be easier to help with code that I am familiar with. Start by getting the first example to work, and please read all of the tutorial carefully as it may help you to figure out the problem.

...R

5

I have already done this. I used codes identical as in tutorial(just changed CE & CSN pins) and transmitter seems to work fine here's sample:

SimpleTx Starting
Data Sent Message 0 Acknowledge received
Data Sent Message 1 Acknowledge received
Data Sent Message 2 Acknowledge received
Data Sent Message 3 Acknowledge received

So as you see it works fine, but problem starts with the receiver, it doesn't show anything juts first line:

SimpleRx Starting

and that's it, nothing else happens(transmitter is still on and transmitting). Codes in this tutorial are very simple to understand so problem must be somewhere else(and also if they worked in tutorial then they should work here).

6

Adampi314:
I have already done this. I used codes identical as in tutorial(just changed CE & CSN pins)

Please post the programs that YOU uploaded to your Arduinos.

Have you de-powered and re-powered your Arduinos after uploading your programs - to get the nRF24s to reset?

...R

7

Well, these programs are identical but here they are:
Transmitter:

// SimpleTx - the master or the transmitter

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN 9
#define CSN_PIN 10

const byte slaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

char dataToSend[10] = "Message 0";
char txNum = '0';

unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 500; // send once per second

void setup() {

Serial.begin(9600);

Serial.println("SimpleTx Starting");

radio.begin();
radio.setAutoAck(false);
radio.setDataRate( RF24_250KBPS );

radio.setRetries(3,5); // delay, count
radio.openWritingPipe(slaveAddress);
}

//====================

void loop() {
currentMillis = millis();
if (currentMillis - prevMillis >= txIntervalMillis) {
send();
prevMillis = millis();
}
}

//====================

void send() {

bool rslt;
rslt = radio.write( &dataToSend, sizeof(dataToSend) );
// Always use sizeof() as it gives the size as the number of bytes.
// For example if dataToSend was an int sizeof() would correctly return 2

Serial.print("Data Sent ");
Serial.print(dataToSend);
if (rslt) {
Serial.println(" Acknowledge received");
updateMessage();
}
else {
Serial.println(" Tx failed");
}
}

//================

void updateMessage() {
// so you can see that new data is being sent
txNum += 1;
if (txNum > '9') {
txNum = '0';
}
dataToSend[8] = txNum;
}

Receiver:

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN 9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
bool newData = false;

//===========

void setup() {

Serial.begin(9600);

Serial.println("SimpleRx Starting");
radio.begin();
radio.setDataRate( RF24_250KBPS );
radio.openReadingPipe(1, thisSlaveAddress);
radio.startListening();
}

//=============

void loop() {
getData();
showData();
}

//==============

void getData() {
if ( radio.available() ) {
radio.read( &dataReceived, sizeof(dataReceived) );
newData = true;
}
}

void showData() {
if (newData == true) {
Serial.print("Data received ");
Serial.println(dataReceived);
newData = false;
}
}

As you see, those are the basic programs from tutorial, responses I have posted before

8

Please try to help us to help you. When posting code please use the code button </>
codeButton.png

so your code 
looks like this

and is easy to copy to a text editor See How to use the Forum

You will have seen how it looks in my Tutorial.

...R

9

Right, sorry about that, I will post code in this code lines, and what about the problem, what is wrong with this communication ?

10

Adampi314:
and what about the problem,

I can't answer that until you post the code in a way that I can study it.

...R

11

Ok, sorry about that, here are all codes:

Simple Transmitter:

// SimpleTx - the master or the transmitter

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>


#define CE_PIN   9
#define CSN_PIN 10

const byte slaveAddress[5] = {'R','x','A','A','A'};


RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

char dataToSend[10] = "Message 0";
char txNum = '0';


unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 500; // send once per second


void setup() {

    Serial.begin(9600);

    Serial.println("SimpleTx Starting");

    radio.begin();
    radio.setAutoAck(false);
    radio.setDataRate( RF24_250KBPS );
   
    radio.setRetries(3,5); // delay, count
    radio.openWritingPipe(slaveAddress);
}

//====================

void loop() {
    currentMillis = millis();
    if (currentMillis - prevMillis >= txIntervalMillis) {
        send();
        prevMillis = millis();
    }
}

//====================

void send() {

    bool rslt;
    rslt = radio.write( &dataToSend, sizeof(dataToSend) );
        // Always use sizeof() as it gives the size as the number of bytes.
        // For example if dataToSend was an int sizeof() would correctly return 2

    Serial.print("Data Sent ");
    Serial.print(dataToSend);
    if (rslt) {
        Serial.println("  Acknowledge received");
        updateMessage();
    }
    else {
        Serial.println("  Tx failed");
    }
}

//================

void updateMessage() {
        // so you can see that new data is being sent
    txNum += 1;
    if (txNum > '9') {
        txNum = '0';
    }
    dataToSend[8] = txNum;
}

Simple Receiver:

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
bool newData = false;

//===========

void setup() {

    Serial.begin(9600);

    Serial.println("SimpleRx Starting");
    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.openReadingPipe(1, thisSlaveAddress);
    radio.startListening();
}

//=============

void loop() {
    getData();
    showData();
}

//==============

void getData() {
    if ( radio.available() ) {
        radio.read( &dataReceived, sizeof(dataReceived) );
        newData = true;
    }
}

void showData() {
    if (newData == true) {
        Serial.print("Data received ");
        Serial.println(dataReceived);
        newData = false;
    }
}

Getting Started:

#include <SPI.h>
#include "RF24.h"

/****************** User Config ***************************/
/***      Set this radio as radio number 0 or 1         ***/
bool radioNumber = 0;

/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(9,10);
/**********************************************************/

byte addresses[][6] = {"1Node","2Node"};

// Used to control whether this node is sending or receiving
bool role = 0;

void setup() {
  Serial.begin(9600);
  Serial.println(F("RF24/examples/GettingStarted"));
  Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));
 
  radio.begin();

  // Set the PA Level low to prevent power supply related issues since this is a
 // getting_started sketch, and the likelihood of close proximity of the devices. RF24_PA_MAX is default.
  radio.setPALevel(RF24_PA_LOW);
 
  // Open a writing and reading pipe on each radio, with opposite addresses
  if(radioNumber){
    radio.openWritingPipe(addresses[1]);
    radio.openReadingPipe(1,addresses[0]);
  }else{
    radio.openWritingPipe(addresses[0]);
    radio.openReadingPipe(1,addresses[1]);
  }
 
  // Start the radio listening for data
  radio.startListening();
}

void loop() {
 
 
/****************** Ping Out Role ***************************/ 
if (role == 1)  {
   
    radio.stopListening();                                    // First, stop listening so we can talk.
   
   
    Serial.println(F("Now sending"));

    unsigned long start_time = micros();                             // Take the time, and send it.  This will block until complete
     if (!radio.write( &start_time, sizeof(unsigned long) )){
       Serial.println(F("failed"));
     }
       
    radio.startListening();                                    // Now, continue listening
   
    unsigned long started_waiting_at = micros();               // Set up a timeout period, get the current microseconds
    boolean timeout = false;                                   // Set up a variable to indicate if a response was received or not
   
    while ( ! radio.available() ){                             // While nothing is received
      if (micros() - started_waiting_at > 200000 ){            // If waited longer than 200ms, indicate timeout and exit while loop
          timeout = true;
          break;
      }     
    }
       
    if ( timeout ){                                             // Describe the results
        Serial.println(F("Failed, response timed out."));
    }else{
        unsigned long got_time;                                 // Grab the response, compare, and send to debugging spew
        radio.read( &got_time, sizeof(unsigned long) );
        unsigned long end_time = micros();
       
        // Spew it
        Serial.print(F("Sent "));
        Serial.print(start_time);
        Serial.print(F(", Got response "));
        Serial.print(got_time);
        Serial.print(F(", Round-trip delay "));
        Serial.print(end_time-start_time);
        Serial.println(F(" microseconds"));
    }

    // Try again 1s later
    delay(1000);
  }



/****************** Pong Back Role ***************************/

  if ( role == 0 )
  {
    unsigned long got_time;
   
    if( radio.available()){
                                                                    // Variable for the received timestamp
      while (radio.available()) {                                   // While there is data ready
        radio.read( &got_time, sizeof(unsigned long) );             // Get the payload
      }
     
      radio.stopListening();                                        // First, stop listening so we can talk   
      radio.write( &got_time, sizeof(unsigned long) );              // Send the final one back.     
      radio.startListening();                                       // Now, resume listening so we catch the next packets.     
      Serial.print(F("Sent response "));
      Serial.println(got_time); 
   }
 }




/****************** Change Roles via Serial Commands ***************************/

  if ( Serial.available() )
  {
    char c = toupper(Serial.read());
    if ( c == 'T' && role == 0 ){     
      Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK"));
      role = 1;                  // Become the primary transmitter (ping out)
   
   }else
    if ( c == 'R' && role == 1 ){
      Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK"));     
       role = 0;                // Become the primary receiver (pong back)
       radio.startListening();
       
    }
  }


}

Connection check:

#include <RF24.h>
#include <SPI.h>
#include <nRF24L01.h>
#include <printf.h>

#define CE_PIN   9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
bool newData = false;


void setup() {
    Serial.begin(9600);
    printf_begin();

    Serial.println("CheckConnection Starting");
    Serial.println();
    Serial.println("FIRST WITH THE DEFAULT ADDRESSES after power on");
    Serial.println("  Note that RF24 does NOT reset when Arduino resets - only when power is removed");
    Serial.println("  If the numbers are mostly 0x00 or 0xff it means that the Arduino is not");
    Serial.println("     communicating with the nRF24");
    Serial.println();
    radio.begin();
    radio.printDetails();
    Serial.println();
    Serial.println();
    Serial.println("AND NOW WITH ADDRESS AAAxR  0x41 41 41 78 52   ON P1");
    Serial.println(" and 250KBPS data rate");
    Serial.println();
    radio.openReadingPipe(1, thisSlaveAddress);
    radio.setDataRate( RF24_250KBPS );
    radio.printDetails();
    Serial.println();
    Serial.println();
}


void loop() {

}

Those are all the codes I used, responses samples I have posted before, I hope it's ok this time.

12

In Reply #4 you said ". I used codes identical as in tutorial(just changed CE & CSN pins) ". However the two Tx and Rx programs in Reply #10 are using the same CE and CSN pins as in my Tutorial.

Can you confirm that you have carried out your tests using pins 9 and 10, and, if you have been using other pins then please post the programs that you are actually using.

...R

PS... I only wanted you to post the pair of programs you are using in your test.

13

Yes, I changed the CE and CSN pins on arduino after I my previous ones didn't work(I used 8 and 10 previously), so I reconnected pins to 9 and 10, this is last version that I uploaded, and is unchanged in any way.

14

You have made changes to my code. Just try my pair of programs with NO changes and see what happens. If it does nor work then please post the output from both programs.

...R

15

Ok, here are the two codes:

Transmitter:

// SimpleTx - the master or the transmitter

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>


#define CE_PIN   9
#define CSN_PIN 10

const byte slaveAddress[5] = {'R','x','A','A','A'};


RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

char dataToSend[10] = "Message 0";
char txNum = '0';


unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000; // send once per second


void setup() {

    Serial.begin(9600);

    Serial.println("SimpleTx Starting");

    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.setRetries(3,5); // delay, count
    radio.openWritingPipe(slaveAddress);
}

//====================

void loop() {
    currentMillis = millis();
    if (currentMillis - prevMillis >= txIntervalMillis) {
        send();
        prevMillis = millis();
    }
}

//====================

void send() {

    bool rslt;
    rslt = radio.write( &dataToSend, sizeof(dataToSend) );
        // Always use sizeof() as it gives the size as the number of bytes.
        // For example if dataToSend was an int sizeof() would correctly return 2

    Serial.print("Data Sent ");
    Serial.print(dataToSend);
    if (rslt) {
        Serial.println("  Acknowledge received");
        updateMessage();
    }
    else {
        Serial.println("  Tx failed");
    }
}

//================

void updateMessage() {
        // so you can see that new data is being sent
    txNum += 1;
    if (txNum > '9') {
        txNum = '0';
    }
    dataToSend[8] = txNum;
}

Receiver:

// SimpleRx - the slave or the receiver

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
bool newData = false;

//===========

void setup() {

    Serial.begin(9600);

    Serial.println("SimpleRx Starting");
    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.openReadingPipe(1, thisSlaveAddress);
    radio.startListening();
}

//=============

void loop() {
    getData();
    showData();
}

//==============

void getData() {
    if ( radio.available() ) {
        radio.read( &dataReceived, sizeof(dataReceived) );
        newData = true;
    }
}

void showData() {
    if (newData == true) {
        Serial.print("Data received ");
        Serial.println(dataReceived);
        newData = false;
    }
}

Here is response with module 1 as transmitter and module 2 as receiver:

module 1:

SimpleTx Starting
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed

module 2:

SimpleRx Starting

now the other way, module 1 as receiver and 2 as transmitter:

module 1:

SimpleRx Starting

module 2:

SimpleTx Starting
Data Sent Message 0 Acknowledge received
Data Sent Message 1 Acknowledge received
Data Sent Message 2 Acknowledge received
Data Sent Message 3 Acknowledge received
Data Sent Message 4 Acknowledge received

I just used your unchanged codes, I posted above and responses are also above. I hope it looks good this time, yet still what is the problem ?

16

Adampi314:
I hope it looks good this time, yet still what is the problem ?

The code is fine now, but I don't know what the problem is. If the Tx is receiving an acknowledgement it suggests that the Rx is getting the data.

Try the pair of programs in the second example which has a two-way flow of data - it may help with diagnosis.

IIRC you have already used the connection test program on both Arduinos and it worked properly.

One small thing, you said "with module 1 as transmitter and module 2 as receiver". I presume by "module" you mean the Arduino and the nRF24 as a pair - rather than swapping the nRF24 to a different Arduino.

...R

17

Yes, by module I mean arduino and nRF24L01 module connected together.
I have uploaded those second pair of codes, same as in example but I will post them here:

Tx Ack Payload:

// SimpleTxAckPayload - the master or the transmitter

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>


#define CE_PIN   9
#define CSN_PIN 10

const byte slaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN); // Create a Radio

char dataToSend[10] = "Message 0";
char txNum = '0';
int ackData[2] = {-1, -1}; // to hold the two values coming from the slave
bool newData = false;

unsigned long currentMillis;
unsigned long prevMillis;
unsigned long txIntervalMillis = 1000; // send once per second

//===============

void setup() {

    Serial.begin(9600);
    Serial.println(F("Source File /mnt/sdb1/SGT-Prog/Arduino/ForumDemos/nRF24Tutorial/SimpleTxAckPayload.ino"));
    Serial.println("SimpleTxAckPayload Starting");

    radio.begin();
    radio.setDataRate( RF24_250KBPS );

    radio.enableAckPayload();

    radio.setRetries(3,5); // delay, count
    radio.openWritingPipe(slaveAddress);
}

//=============

void loop() {

    currentMillis = millis();
    if (currentMillis - prevMillis >= txIntervalMillis) {
        send();
    }
    showData();
}

//================

void send() {

    bool rslt;
    rslt = radio.write( &dataToSend, sizeof(dataToSend) );
        // Always use sizeof() as it gives the size as the number of bytes.
        // For example if dataToSend was an int sizeof() would correctly return 2

    Serial.print("Data Sent ");
    Serial.print(dataToSend);
    if (rslt) {
        if ( radio.isAckPayloadAvailable() ) {
            radio.read(&ackData, sizeof(ackData));
            newData = true;
        }
        else {
            Serial.println("  Acknowledge but no data ");
        }
        updateMessage();
    }
    else {
        Serial.println("  Tx failed");
    }

    prevMillis = millis();
 }


//=================

void showData() {
    if (newData == true) {
        Serial.print("  Acknowledge data ");
        Serial.print(ackData[0]);
        Serial.print(", ");
        Serial.println(ackData[1]);
        Serial.println();
        newData = false;
    }
}

//================

void updateMessage() {
        // so you can see that new data is being sent
    txNum += 1;
    if (txNum > '9') {
        txNum = '0';
    }
    dataToSend[8] = txNum;
}

Rx Ack Payload:

// SimpleRxAckPayload- the slave or the receiver

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

#define CE_PIN   9
#define CSN_PIN 10

const byte thisSlaveAddress[5] = {'R','x','A','A','A'};

RF24 radio(CE_PIN, CSN_PIN);

char dataReceived[10]; // this must match dataToSend in the TX
int ackData[2] = {109, -4000}; // the two values to be sent to the master
bool newData = false;

//==============

void setup() {

    Serial.begin(9600);

    Serial.println("SimpleRxAckPayload Starting");
    radio.begin();
    radio.setDataRate( RF24_250KBPS );
    radio.openReadingPipe(1, thisSlaveAddress);

    radio.enableAckPayload();
    
    radio.startListening();

    radio.writeAckPayload(1, &ackData, sizeof(ackData)); // pre-load data
}

//==========

void loop() {
    getData();
    showData();
}

//============

void getData() {
    if ( radio.available() ) {
        radio.read( &dataReceived, sizeof(dataReceived) );
        updateReplyData();
        newData = true;
    }
}

//================

void showData() {
    if (newData == true) {
        Serial.print("Data received ");
        Serial.println(dataReceived);
        Serial.print(" ackPayload sent ");
        Serial.print(ackData[0]);
        Serial.print(", ");
        Serial.println(ackData[1]);
        newData = false;
    }
}

//================

void updateReplyData() {
    ackData[0] -= 1;
    ackData[1] -= 1;
    if (ackData[0] < 100) {
        ackData[0] = 109;
    }
    if (ackData[1] < -4009) {
        ackData[1] = -4000;
    }
    radio.writeAckPayload(1, &ackData, sizeof(ackData)); // load the payload for the next time
}

And here are the responses:

First with module 1 as receiver and module 2 as transmitter:

module 1:

SimpleRxAckPayload Starting

module 2:

SimpleTxAckPayload Starting
Data Sent Message 0 Acknowledge but no data
Data Sent Message 1 Acknowledge but no data
Data Sent Message 2 Acknowledge but no data
Data Sent Message 3 Acknowledge but no data
Data Sent Message 4 Acknowledge but no data

now the other way, module 1 as transmitter and module 2 as receiver:

module 1:

SimpleTxAckPayload Starting
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed
Data Sent Message 0 Tx failed

module 2:

SimpleRxAckPayload Starting

Looks like module 1 has some problems with transmitting and receiving.

18

I think you need to get at least one more nRF24 module - the only simple way to diagnose a faulty wireless module is to substitute another one.

...R

19

Ok, today I ordered two more I will write more when I have access to them.