Is the code correct? Nrf24l01

Question

I'm am a beginner, so I'm sorry I have written this wrong.

Is this piece of code correct? If not where?

Transmitter:

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

int* Msg, mSg, msG;

RF24 radio(9, 10);
const uint8_t pipe = 1;

void setup() {
  // put your setup code here, to run once:
  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.openWritingPipe(pipe);
}

void loop() {
  // put your main code here, to run repeatedly:
  Msg = analogRead(A1);
  radio.write(Msg, sizeof(Msg));
  mSg = analogRead(A2);
  radio.write(mSg, sizeof(mSg));
  msG = analogRead(A3);
  radio.write(msG, sizeof(msG));
  delay(100);
}

Receiver:

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

#define in1 2
#define in2 3
#define in3 4
#define in4 5

#define in5 A2
#define in6 A3
#define in7 A4
#define in8 A5

const int maxMsgLength = 64;
char Msg[maxMsgLength];
const int maxmSgLength = 64;
char mSg[maxmSgLength];
const int maxmsGLength = 64;
char msG[maxmsGLength];

RF24 radio(9, 10);
const uint8_t pipe = 1;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.openReadingPipe(1, pipe);
  radio.startListening();
}

void loop() {
  // put your main code here, to run repeatedly:
  if (radio.available()) {
    radio.read(Msg, maxMsgLength - 1);
    radio.read(mSg, maxmSgLength - 1);
    radio.read(msG, maxmsGLength - 1);
  }

  int xAxis = Msg;
  int yAxis = mSg;
  int YAxis = msG;

  if (xAxis < 450) {
    // Forward
    digitalWrite(in1, 1);
    digitalWrite(in2, 0);
    digitalWrite(in3, 1);
    digitalWrite(in4, 0);
    Serial.println("Forward");
  }
  else if (xAxis > 550) {
    // Backward
    digitalWrite(in1, 0);
    digitalWrite(in2, 1);
    digitalWrite(in3, 0);
    digitalWrite(in4, 1);
    Serial.println("Backward");
  }
  else {
    // Stop
    digitalWrite(in1, 0);
    digitalWrite(in2, 0);
    digitalWrite(in3, 0);
    digitalWrite(in4, 0);
    Serial.println("Stop");
  }

  if (yAxis < 450) {
    // Left
    digitalWrite(in5, 1);
    digitalWrite(in6, 0);
    Serial.println("Left");
  }
  else if (yAxis > 550) {
    // Right
    digitalWrite(in5, 0);
    digitalWrite(in6, 1);
    Serial.println("Right");
  }
  else {
    // Stop
    digitalWrite(in5, 0);
    digitalWrite(in6, 0);
    Serial.println("Stop");
  }

  if (yAxis < 450) {
    // Flipper Up
    digitalWrite(in7, 1);
    digitalWrite(in8, 0);
    Serial.println("Up");
  }
  else if (yAxis > 550) {
    // Flipper Down
    digitalWrite(in7, 0);
    digitalWrite(in8, 1);
    Serial.println("Down");
  }
  else {
    // Stop
    digitalWrite(in7, 0);
    digitalWrite(in8, 0);
    Serial.println("Mid");
  }
  delay(250);
}

Edit:

Transmitter:

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

int x, y, f;

RF24 radio(9, 10);
const uint8_t pipe = 1;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.openWritingPipe(pipe);
}

void loop() {
  // put your main code here, to run repeatedly:
  x = analogRead(A1);
  radio.write(x, sizeof(x));
  y = analogRead(A2);
  radio.write(y, sizeof(y));
  f = analogRead(A3);
  radio.write(f, sizeof(f));
  delay(100);
}

Receiver:

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

#define in1 2
#define in2 3
#define in3 4
#define in4 5

#define in5 A2
#define in6 A3
#define in7 A4
#define in8 A5

int x;
int y;
int f;

RF24 radio(9, 10);
const uint8_t pipe = 1;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.openReadingPipe(1, pipe);
  radio.startListening();
}

void loop() {
  // put your main code here, to run repeatedly:
  if (radio.available()) {
    radio.read(&x, sizeof(x));
    radio.read(&y, sizeof(y));
    radio.read(&f, sizeof(f));
  }

  if (x < 450) {
    // Forward
    digitalWrite(in1, 1);
    digitalWrite(in2, 0);
    digitalWrite(in3, 1);
    digitalWrite(in4, 0);
    Serial.println("Forward");
  }
  else if (x > 550) {
    // Backward
    digitalWrite(in1, 0);
    digitalWrite(in2, 1);
    digitalWrite(in3, 0);
    digitalWrite(in4, 1);
    Serial.println("Backward");
  }
  else {
    // Stop
    digitalWrite(in1, 0);
    digitalWrite(in2, 0);
    digitalWrite(in3, 0);
    digitalWrite(in4, 0);
    Serial.println("Stop");
  }
  if(x > 1023)x = 1023;
  if(x < 0)x = 0;

  if (y < 450) {
    // Left
    digitalWrite(in5, 1);
    digitalWrite(in6, 0);
    Serial.println("Left");
  }
  else if (y > 550) {
    // Right
    digitalWrite(in5, 0);
    digitalWrite(in6, 1);
    Serial.println("Right");
  }
  else {
    // Stop
    digitalWrite(in5, 0);
    digitalWrite(in6, 0);
    Serial.println("Stop");
  }
  if(y > 1023)y = 1023;
  if(y < 0)y = 0;

  if (f < 450) {
    // Flipper Up
    digitalWrite(in7, 1);
    digitalWrite(in8, 0);
    Serial.println("Up");
  }
  else if (f > 550) {
    // Flipper Down
    digitalWrite(in7, 0);
    digitalWrite(in8, 1);
    Serial.println("Down");
  }
  else {
    // Stop
    digitalWrite(in7, 0);
    digitalWrite(in8, 0);
    Serial.println("Mid");
  }
  if(f > 1023)f = 1023;
  if(f < 0)f = 0;

  Serial.println(x);
  Serial.println(y);
  Serial.println(f);
  delay(250);
}

Thank you for your time.

Answer 1

I see (at least one ) problem.

First remove the * from:

int* Msg, mSg, msG;

Because it should store integers (numbers), not pointers to numbers.

Also, make the variables better. These almost identical names are quite confusing (name them x, y or z or a better name).

What you are doing is sending the 3 integers as integers (meaning that each integer is 2 bytes), so you send 6 bytes.

But in the receiver, you read characters, you have to replace this by:

• Changing char to int for the 3 variables in the receiver side
• Also here, change the names
• Remove the constants for the length (64)

• Instead read the code as you write it:

  int xAxis; radio.read(&xAxis, sizeof(int));

& means: address, the read function stores the value in xAxis (so you don't have to copy it afterwards). Also print out the value after the read so you can check it.