Serialize it in JSON Format and send it by RF24 library !

[oussama415]

Hi, I have a problem when i use ArduinoJson with the RF24 library I want to serialize it in JSON Format and after that sending it with RF24 !!!!

When i copy a sample code in my RF24 code, before sending by RF24, the function serialize return nothing {} : what it return !!!

Can you help me please 👍

[bblanchon]

Hi @oussama415,

Which sample program are you referring to?

Best regards, Benoit

[oussama415]

Hi @bblanchon Thanks for your fast reply This is a simple code for transmitting

#include <RF24Network.h>
#include <RF24.h>
#include <SPI.h>
#include <ArduinoJson.h>

RF24 radio(7, 8);               // nRF24L01 (CE,CSN) (7,8)
RF24Network network(radio);      // Include the radio in the network
const uint16_t this_node = 00;   // Address of this node in Octal format 
const uint16_t node01 = 01;    

void setup()
{
  Serial.begin(115200);
  SPI.begin();
  radio.begin();
  network.begin(90, this_node);  
  radio.setDataRate(RF24_2MBPS);
}
void loop()
{
  network.update();
  StaticJsonDocument<300> doc;
  doc["var1"] = 50;

  RF24Adapter radioForArduinoJson(radio); // Not sending 
  serializeJson(doc, radioForArduinoJson); // I get nothing like this : {}

//---------------------- Sending normally char type----------------------------//
  //  RF24NetworkHeader header1(node01);     // (Address where the data is going)
  //  network.write(header1, &json1, sizeof(json1)); 
//---------------------- Sending normally char type----------------------------//

}

i have nothing in return for the line : serializeJson(doc, radioForArduinoJson); i want to serialize in JSON Format and send it by radio

I see you have already make a class for RF24Adapter, i don't know when exactly i copy it !!!

This is the class :

class RF24Adapter {
 public:
  RF24Adapter(RF24 &radio) : _radio(&radio) {}

  int read() {
    char buf[1];
    _radio->read(buf, 1);
    return buf[0];
  }

  size_t readBytes(char *buffer, size_t length) {
    _radio->read(buffer, static_cast<uint8_t>(length));
    return length;
  }

  size_t write(uint8_t c) {
    return _radio->write(&c, 1) ? 1 : 0;
  }

  size_t write(const uint8_t *buffer, size_t length) {
    return _radio->write(buffer, static_cast<uint8_t>(length)) ? length : 0;
  }

 private:
  RF24 *_radio;
};

Thanks for your help !

[bblanchon]

Hi @oussama415,

I have no experience with RF24Network and I cannot spot any obvious mistake in the code, so I cannot help you. Here are a few ideas to troubleshoot this issue:

1. Get ArduinoJson out of the way:
   1. make sure you can transmit plain text (e.g "hello world")
   2. try to send the string "{\"var1\":50}" to simulate the work of the library
2. Restore ArduinoJson
   1. try with a temporary buffer, or a String
   2. if it works, you can retry with RF24Adapter
3. Ask for help
   1. If nothing works, please contact the RF24Network team
   2. If you get no answer, try stackoverflow or the Arduino Forum

Please let me know how you solve your issue, so other users can find the answer in this conversation. If there is enough material, I will add a dedicated page on arduinojson.org

Best regards, Benoit

[bblanchon]

Any progress, @oussama415?

[oussama415]

No progress, the solution is to make a message with JSON format a with a char and send it by RF24 but the problem is the maximum we can send but RF24 is 32 bytes !!!

Le ven. 1 oct. 2021 à 07:26, Benoît Blanchon @.***> a écrit :

Any progress, @oussama415 https://github.com/oussama415?

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KHOURIBACHE OUSSAMA

Ingénieur en Génie Electrique et Contrôle Industriel - FST Mohammedia

Email : @.***

Tel : 06.08.28.23.47

[bblanchon]

I didn't know RF24 was limited to 32 bytes. That makes it a very bad candidate for JSON.

I recommend that you send binary structures instead. If you don't know what I'm talking about, please watch the first part of this video.