[SOLVED] nRF24L01

Thread Starter

wernerdejong1972

Joined Sep 10, 2021
12
Hi all

I´m trying to get to arduinos to communicate together througt a nRF24L01. On the receiver side I want to turn the builtin LED to turn on every time I press a button on the transmitter. Furthermore I want to show a message on the Serial monitor that tells me the state off the button.
The part with the serial monitor works as planned but the builtin LED doesn´t turn on. What am I doing wrong?

C:
//RECEIVER
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
RF24 radio(9, 10); // CE, CSN
const byte address[6] = "00001";
boolean button_state = 0;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);

  Serial.begin(9600);
  radio.begin();
  radio.openReadingPipe(0, address);   //Setting the address at which we will receive the data
  radio.setPALevel(RF24_PA_MIN);       //You can set this as minimum or maximum depending on the distance between the transmitter and receiver.
  radio.startListening();              //This sets the module as receiver
}
void loop()
{
  if (radio.available())              //Looking for the data.
  {
    char text[32] = "";                 //Saving the incoming data
    radio.read(&text, sizeof(text));    //Reading the data
    radio.read(&button_state, sizeof(button_state));    //Reading the data
    if (button_state == HIGH)
    {
      Serial.println(text);
      delay(5);
      digitalWrite(LED_BUILTIN, HIGH);
    }
    else
    {
      Serial.println(text);
      delay(5);
      digitalWrite(LED_BUILTIN, LOW);
    }
  }
  delay(5);
}
Moderator edit: added code tags like this [code] ... your code... [/code]
 

Thread Starter

wernerdejong1972

Joined Sep 10, 2021
12
Sure :)

C-like:
// Transmitter

#include <SPI.h>

#include <nRF24L01.h>

#include <RF24.h>

RF24 radio(9, 10); // CE, CSN       

const byte address[6] = "00001";     //Byte of array representing the address. This is the address where we will send the data. This should be same on the receiving side.

int button_pin = 2;

boolean button_state = 0;


void setup() {

pinMode(button_pin, INPUT);


radio.begin();                  //Starting the Wireless communication

radio.openWritingPipe(address); //Setting the address where we will send the data

radio.setPALevel(RF24_PA_MIN);  //You can set it as minimum or maximum depending on the distance between the transmitter and receiver.

radio.stopListening();          //This sets the module as transmitter

}

void loop()

{

button_state = digitalRead(button_pin);

if(button_state == HIGH)

{

const char text[] = "Your Button State is HIGH";

radio.write(&text, sizeof(text));                  //Sending the message to receiver

}

else

{

const char text[] = "Your Button State is LOW";

radio.write(&text, sizeof(text));                  //Sending the message to receiver

}

radio.write(&button_state, sizeof(button_state));  //Sending the message to receiver

delay(1000);

}
 

Thread Starter

wernerdejong1972

Joined Sep 10, 2021
12
When I remove:
radio.begin();
radio.openReadingPipe(0, address);
radio.setPALevel(RF24_PA_MIN);
radio.startListening();

and add
digitalWrite(LED_BUILTIN, HIGH);
in setup, the builtin LED turn on. Otherwise it´s impossible to get the LED to turn on.
 

Ya’akov

Joined Jan 27, 2019
6,853
Try adding a delay at the end of the on button state block, just to check.

C++:
    {
      Serial.println(text);
      digitalWrite(LED_BUILTIN, HIGH);
      delay(1000);     
    }
 

Thread Starter

wernerdejong1972

Joined Sep 10, 2021
12
Do you mean this?
C-like:
if (button_state == HIGH)

    {

      //Serial.println(text);

      digitalWrite(LED_BUILTIN, HIGH);

      delay(1000);

    }

    else

    {

      //Serial.println(text);

      digitalWrite(LED_BUILTIN, HIGH);

      delay(1000);

    }

  }
(didn´t work either...)
 
Last edited by a moderator:

Ya’akov

Joined Jan 27, 2019
6,853
Yes, that's what I meant. So I have this straight, when the serial code is uncommented, it does write to the serial monitor, correct?
 

Thread Starter

wernerdejong1972

Joined Sep 10, 2021
12
" SPI uses pin 13, so you can’t really use the built in LED while using SPI. "
could this be the solution? I´m not sure, because I´ve also tried pin3 without luck.
 

Ya’akov

Joined Jan 27, 2019
6,853
" SPI uses pin 13, so you can’t really use the built in LED while using SPI. "
could this be the solution? I´m not sure, because I´ve also tried pin3 without luck.
See above. pin 13 is hardwired to the builtin LED. You will ahve to put an external led on a different pin to make it work.
 
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