Arduino and nRF24L01

Projects Programming
1

Hello,
I am working on an arduino project with the nRF24L01 module.
Unfortunately I can't get it to work. Can someone tell me what I am doing wrong?

I have 2 nrf24l01 modules. This is the version with antenna.
I tried to follow the steps on this site:

I am using 1 arduino mega and 1 arduino uno. The power of the nRF modules comes directly from the arduino 3v3.

I have tried several things:
-get the power from an external power source 3v3 and 5v (with regulator)
-from the arduino 5v with a voltage regulator

I use the following code (also from the site):

/*
* Arduino Wireless Communication Tutorial
*     Example 1 - Transmitter Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

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

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_MIN);
  radio.stopListening();
}

void loop() {
  const char text[] = "Hello World";
  radio.write(&text, sizeof(text));
  delay(1000);
}

and

/*
* Arduino Wireless Communication Tutorial
*       Example 1 - Receiver Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

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

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.openReadingPipe(0, address);
  radio.setPALevel(RF24_PA_MIN);
  radio.startListening();
}

void loop() {
  if (radio.available()) {
    char text[32] = "";
    radio.read(&text, sizeof(text));
    Serial.println(text);
  }
}

I get nothing in my serial plotter while everything is on and should work.
Does anyone know what I am doing wrong or what else I can test?
Greetings Justin

2

Do you mean Serial monitor ?

3

if find it a good idea after radio.begin() to check the connection, e.g.

void setup() {
  Serial.begin(115200);
  delay(3000);
  Serial.println("\n\nNano > NRF24L01 Receive");
  radio.begin();
  if (radio.isChipConnected())
    Serial.println("Receiver NF24 connected to SPI");
  else {
    Serial.println("NF24 is NOT connected to SPI");
    while (1)
      ;
  }

tells you that the basic SPI connection is working or not

also have a look at Power Stability Issues with RF24 Radio Modules by @gilshultz

4

Thanks for the response,
i replaced the arduino mega with an arduino nano.
i added the code and both the arduino uno and the nano both showed Nano > NRF24L01 Receive Receiver NF24 connected to SPI.

The codes are now as follows:

arduino uno

/*
* Arduino Wireless Communication Tutorial
*       Example 1 - Receiver Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

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

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.openReadingPipe(0, address);
  radio.setPALevel(RF24_PA_MIN);
  radio.startListening();

  delay(3000);
  Serial.println("\n\nNano > NRF24L01 Receive");
  radio.begin();
  if (radio.isChipConnected())
    Serial.println("Receiver NF24 connected to SPI");
  else {
    Serial.println("NF24 is NOT connected to SPI");
    while (1)
      ;
  }
}

void loop() {
  if (radio.available()) {
    char text[32] = "";
    radio.read(&text, sizeof(text));
    Serial.println(text);
  }
}

arduino nano

/*
* Arduino Wireless Communication Tutorial
*     Example 1 - Transmitter Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

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

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_MIN);
  radio.stopListening();

  Serial.begin(9600);
  delay(3000);
  Serial.println("\n\nNano > NRF24L01 Receive");
  radio.begin();
  if (radio.isChipConnected())
    Serial.println("Receiver NF24 connected to SPI");
  else {
    Serial.println("NF24 is NOT connected to SPI");
    while (1)
      ;
  }
}

void loop() {
  const char text[] = "Hello World";
  radio.write(&text, sizeof(text));
  delay(1000);
}

Unfortunately my serial monitor remains completely empty after the Nano > NRF24L01 Receive Receiver NF24 connected to SPI message.
I am also now using an external power supply.

5

You don't check the return status of radio.begin().

radio.printDetails() would be full of great debugging info. But you don't call it.

You don't check the return status of radio.write().

You never look at radio.failureDetected to see if the library has detected a fault.

The library gives you all kinds of great tools to assist in debugging communication problems.

You don't appear to be using many of them.

You might want to rethink that approach.

6

But not the cleanest one: 2xAA battery (3V).

7

you appear to call radio.begin() twice - try removing the second call which probably clears your initial setup