NRF24L01 debugging help

Question

I have been trying to get the NRF24L01 to transmit the "hello World", Though the devices are talking to each other they are reading scrambled data. I have looked everywhere for support but unfortunately tried solutions as much as I can. I have attached the code below and the output.

The steps for fixing from my side:

• Checked the wiring
• rechecked the code and the address
• Used a capacitor
• Changed the baud rate to the transceiver specification and random baud rates

I need a new perspective please help!!

Transmitter:

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

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

const byte address[6] = "00001";

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

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

Receiver:

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

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

const byte address[6] = "00001";

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

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

I would like to add I have some basic knowledge of Arduino.

Output: ?????????????????????????????????/

????????????????????

??????????????????????????????????

???????????????????????

Answer 1

Your problem is in the usage of &text. text is a pointer to a block of memory with text in it. Thus &text is a pointer to the variable that stores the pointer to the block of memory that stores the text.

That is, for example:

• "Hello world" is stored starting at address 10.
• text is a variable stored at addresses 20 and 21 (it's two bytes to store the address of Hello world)
• Using text gives you 10 but using &text gives you 20.

Since text is already a pointer you just need to cast it to the right type of pointer for the target function (uint8_t * possibly).