NRF24L01 transceiver not receiving correct data

genius_coder · September 6, 2023, 1:34am

Hi, I am making a RC car using the nRF24l01 transceiver and the RF24 library. This is my code:

Controller:

//RADIO CODE FROM THE EXAMPLE IN RF24 LIBRARY: https://nrf24.github.io/RF24/examples_2GettingStarted_2GettingStarted_8ino-example.html

//RADIO
#include <RF24.h>
#include <RF24_config.h>
#include <nRF24L01.h>
#include <printf.h>

#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);

const uint8_t pipeOut  = 0xE8E8F0F0E1LL;

bool radioNumber = 1;

bool role = true;

int payload = 0;

//CONTROLS

int SandDPot = A0; //Stop or Go, Forwards or Backwards, and Speed
int turnPot = A1; //Turn degrees

int order = 0; /* 0 = send stop,go,forwards&backwards
                  1 = send speed
                  2 = send turn degrees*/
int SandD; //see line 23
bool gORs; //go or stop
bool fORb; //forwards or backwards
int speed;
int turn;



void setup() {
  
  //RADIO
  if (!radio.begin()){
    while (1) {}
  }

  radio.setPALevel(RF24_PA_LOW);

  radio.setPayloadSize(sizeof(payload));

  radio.openWritingPipe(pipeOut);

  radio.stopListening();

  //CONTROLS 

  pinMode(SandDPot, INPUT);
  pinMode(turnPot, INPUT);

  gORs = false; //stopped
  fORb = true; //if on go, go forward
}

void loop() {

  if (order != 2){ //not sending turn
    SandD = analogRead(SandDPot) - 511.5; //get input make into range of 511 to -511
    if (order == 0){ //sending stop,go,forwards&backwards
      if (SandD != 0){ //0 = stopped
        gORs = true; //moving
        if (SandD > 0){ //if > 0 moving forward
          fORb = true;
          payload = 1;
        } else {
          fORb = false; //going backwards
          payload = 2;
        }
        order++; //check speed
      } else {
        gORs = false; //stopped
        payload = 0;
        order = 0; //check if moving again
      }
      radio.write(&payload, sizeof(int));
    } else { // sending speed
      if (fORb == true){ //going forwards
        speed = map(SandD, 0, 511, 0, 255); //convert to pwm
      } else { //going backwards
        speed = map(SandD, 0, -511, 0, 128); //half as fast
      }
      payload = speed + 3; //when recieving, if > 3 and =< 258, recieving speed
      radio.write(&payload, sizeof(int));
      order++; //check turn 
    }
  } else { //order == 3, checking turn
    turn = analogRead(turnPot); //get input from potentiometer
    turn = map(turn, 0, 1023, 0, 180); //convert to 180 degrees for servo
    payload = turn + 258; //when recieving if > 258, recieving turn
    radio.write(&payload, sizeof(int));
  }
}

Car: (I am using the serial monitor to test the receiving)

//RADIO CODE BASED ON THIS EXAMPLE IN LIBRARY: https://nrf24.github.io/RF24/examples_2GettingStarted_2GettingStarted_8ino-example.html

//RADIO

#include <RF24.h>
#include <RF24_config.h>
#include <nRF24L01.h>
#include <printf.h>

#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);

const uint8_t pipeIn = 0xE8E8F0F0E1LL;

bool radioNumber = 1;

bool role = false;

int commands; //commands go to here

//CAR

int turnDeg;
int speed;

void setup() {

  //RADIO

  if (!radio.begin()){
    while (1) {}
  }

  radio.setPALevel(RF24_PA_LOW);

  radio.openReadingPipe(1, pipeIn);

  radio.startListening();

  Serial.begin(9600);
}

void loop() {

  uint8_t pipe;
  uint8_t bytes;
  
  //Get command
  if (radio.available(&pipe)){
    bytes = radio.getPayloadSize();
    radio.read(&commands, bytes);
  }

  if (commands <= 3){ //if recieving go,stop,forwards,&backwards
    if (commands == 0) { //stopping
      Serial.println("stopped");
    } else if (commands == 1) { //forwards
      Serial.println("forward");
    } else { //backwards
      Serial.println("backwards");
    }
  } else if (commands > 3 && commands <= 258){ //if recieving speed
    speed = commands - 3;
    Serial.println("Speed: " + speed);
  } else { // recieving turn
    turnDeg = commands - 258;
    Serial.println("Turn: " + turnDeg);
  }
}

The problem is that when I run the code I get this in the serial monitor:

Thanks!

kolaha · September 6, 2023, 1:51am

what are they doing? did they contain #include "SPI.h" ?

kolaha · September 6, 2023, 2:31am

//RF24 LIBRARY: https://nrf24.github.io/RF24/

//RADIO transmitter
#include <SPI.h>
#include <RF24.h>
#include <printf.h>

#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);

const uint8_t pipeOut  = 0xE8E8F0F0E1LL;
byte payload[2] = {0};

//CONTROLS
const int SandDPot = A0; //Stop or Go, Forwards or Backwards, and Speed
const int turnPot = A1; //Turn degrees

void setup() {
  while (!radio.begin()) {}
  radio.setPALevel(RF24_PA_LOW);
  radio.setPayloadSize(2);
  radio.openWritingPipe(pipeOut);
  radio.stopListening();
  pinMode(SandDPot, INPUT);
  pinMode(turnPot, INPUT);
}

void loop() {
  payload[0] = analogRead(SandDPot) / 4; 
  payload[1] = analogRead(turnPot) / 5.68333333;
  radio.write(&payload, 2);
  delay(20);
}

//RADIO receiver

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

#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);
const uint8_t pipeIn = 0xE8E8F0F0E1LL;

void setup() {
  //RADIO
  while (!radio.begin()) {}
  radio.setPALevel(RF24_PA_LOW);
  radio.openReadingPipe(1, pipeIn);
  radio.startListening();
  Serial.begin(115200);
}

void loop() {
  static byte payload[2] = {0};

  if (radio.available()) {
    radio.read(&payload, 2);
    int speed =payload[0]-128;
    if (abs(speed) < 5)Serial.println("stopped");
    else {
      if (speed > 0) Serial.println("forward");
      else Serial.println("backwards");
    }

    Serial.print("Speed: ");
    Serial.print(speed);
    Serial.print("\tTurn Deg: ");
    Serial.println(payload[1]);
  }
}

genius_coder · September 7, 2023, 2:27am

I tried using this code, but I didn't see anything in the serial monitor.

genius_coder · September 7, 2023, 2:29am

I tried using your code @kolaha, but I didn't see anything in the serial monitor.

genius_coder · September 7, 2023, 2:34am

I think the problem is with the math in the the Loop function, but I am not sure. If anyone can help me figure that out, thanks!

kolaha · September 7, 2023, 6:57am

show how you connect modules

genius_coder · September 8, 2023, 1:56am

I did not use the IRQ.

kolaha · September 8, 2023, 2:17am

nRF24L01+ is 3.3V chip, isn't it?

genius_coder · September 10, 2023, 9:10pm

I am using the YourDuino RoboRED board which has a switch that can change it from operating at 5v to 3.3v.

kolaha · September 10, 2023, 9:53pm

that switch change supply voltage for Atmega328p only or for entire board? how powerful is 3.3V regulator?

or better answer one another question:
Did you successfully run the test sketch and see the nRF module working?

genius_coder · September 10, 2023, 9:55pm

The rx light on the receiving board is on (it is blinking), but the tx light on the sending board is not.
However, a light on the nrf does go on

genius_coder · September 26, 2023, 6:41pm

Using the example code, the nrf did receive the message, but using your code, it did not.

genius_coder · September 26, 2023, 7:45pm

I don't know exactly what was wrong with my code, but I just edited the example code and it worked.

Controller:

#include <SPI.h>
#include "printf.h"
#include "RF24.h"
 
#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);
 
uint8_t address = 0xE8E8F0F0E1LL;

int payload = 0;

int speedPot = A0; //Speed
int turnPot = A1; //Turn degrees

int speed;
int turn;

void setup() {
 
  Serial.begin(115200);
  while (!Serial) {
    // some boards need to wait to ensure access to serial over USB
  }
 
  // initialize the transceiver on the SPI bus
  if (!radio.begin()) {
    Serial.println(F("radio hardware is not responding!!"));
    while (1) {}  // hold in infinite loop
  }
 
  // print example's introductory prompt
  Serial.println(F("RF24/examples/GettingStarted"));
  
  // Set the PA Level low to try preventing power supply related problems
  // because these examples are likely run with nodes in close proximity to
  // each other.
  radio.setPALevel(RF24_PA_LOW);  // RF24_PA_MAX is default.
 
  // save on transmission time by setting the radio to only transmit the
  // number of bytes we need to transmit a int
  radio.setPayloadSize(sizeof(payload));  // int datatype occupies 2 bytes
 
  radio.openWritingPipe(address);
 
  radio.stopListening();  // put radio in TX mode

  //contols 
  pinMode(speedPot, INPUT);
  pinMode(turnPot, INPUT);
}
 
void loop() {
 
  speed = analogRead(speedPot);
  turn = analogRead(turnPot);

  speed = map(speed, 0, 1023, -256, 256);
  turn = map(turn, 0, 1023, 257, 347);

  payload = speed;
  radio.write(&payload, sizeof(int));
  Serial.println(payload);
  delay(1000);
  payload = turn;
  radio.write(&payload, sizeof(int));
  Serial.println(payload);
  delay(1000);
 
}

Receiver:

#include <SPI.h>
#include "printf.h"
#include "RF24.h"
 
#define CE_PIN 7
#define CSN_PIN 8

RF24 radio(CE_PIN, CSN_PIN);
 
uint8_t address = 0xE8E8F0F0E1LL;

int payload = 0;
 
void setup() {
 
  Serial.begin(115200);
  while (!Serial) {
    // some boards need to wait to ensure access to serial over USB
  }
 
  // initialize the transceiver on the SPI bus
  if (!radio.begin()) {
    Serial.println(F("radio hardware is not responding!!"));
    while (1) {}  // hold in infinite loop
  }

  // Set the PA Level low to try preventing power supply related problems
  // because these examples are likely run with nodes in close proximity to
  // each other.
  radio.setPALevel(RF24_PA_LOW);  // RF24_PA_MAX is default.
 
  // save on transmission time by setting the radio to only transmit the
  // number of bytes we need to transmit a int
  radio.setPayloadSize(sizeof(payload));  // int datatype occupies 2 bytes

  radio.openReadingPipe(1, address);

  radio.startListening();  // put radio in RX mode
}
 
void loop() {

  uint8_t pipe;
  if (radio.available(&pipe)) {              
    uint8_t bytes = radio.getPayloadSize();  // get the size of the payload
    radio.read(&payload, bytes);   

    //get speed, direction & turn
    if (payload == 0) {
      Serial.println("Stopped");
    } else if (payload < 0) {
      Serial.print("Backwards: ");
      Serial.println(payload);
    } else if (payload > 0 && payload < 257) {
      Serial.print("Forwards: ");
      Serial.println(payload);
    } else {
      payload = payload - 302;
      Serial.print("Turn: ");
      Serial.println(payload);
    }
  }
}

Thanks @kolaha for trying to solve the problem!

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NRF24L01 transceiver not receiving correct data

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