[Solved] 433 mhz receiver get confuse after receiving some data...

@sly442

Them [code] and [/code] doesn't work here.

https://forum.dronebotworkshop.com/question-suggestion/sticky-post-for-editing/#post-4939

Thank you @robotBuilder for the advice.

Hi All,

I'm doing the remote control project with 2 Arduino's uno and the H bridge motor control. As seen in the articles "Using Inexpensive 433MHz Transmit and Receive Modules with Arduino" and "Wireless Joystick for Arduino Robot Car with nRF24L01+"

So I mixed 2 sketchs to be able to have it work with the RadioHead library and ASK. 

After several hours research and tries I do received the value of axes Y and X as long as I don't touch the joystick, When I move it it freezes.

My goal was to send an array without using string to send it but I tought sending an array value that could contain the x and y value at the same time like " joyVal[2] = {joypoVert, joyposHorz} " but I wasn't able to have it work. So I went back to the String construction of the axes.

So here's the code:

// Transmiter (Joystick)

... 

void loop()
{


  // Read the Joystick X and Y positions
  joyposVert = analogRead(joyVert);
  joyposHorz = analogRead(joyHorz);


  str_joyposVert = String(joyposVert);
  str_joyposHorz = String(joyposHorz);

  // Construction of String

  str_out = str_joyposVert +","+ str_joyposHorz; // max size of the array = 9 cararcters

  // Test


   Serial.print("joyposVert = ");
   Serial.println(joyposVert);
   Serial.print("joyposHorz = ");
   Serial.println(joyposHorz);




  static char *msg = str_out.c_str();

  rf_driver.send((uint8_t *)msg, strlen(msg));
  rf_driver.waitPacketSent();
  delay(50);  // Wait a bit before next transmission
}

------------------

// receiver

... 

void loop()
{
  delay(10);
  if (rf_driver.available())
    Serial.println("Driver available");
  {

    uint8_t buf[9]; // string of xxxx,xxxx (9)
    uint8_t buflen = sizeof(buf);
    if (rf_driver.recv(buf, &buflen))
      str_out = ((char *)buf);

    {
      for (int i = 0; i < str_out.length(); i++){
        if (str_out.substring(i, i+1) == ","){
          str_joyposVert = str_out.substring(0, i);
          str_joyposHorz = str_out.substring(i+1);
        }
      }

      joyposVert = str_joyposVert.toInt();
      joyposHorz = str_joyposHorz.toInt();

      // Test reading value

      Serial.print("joyposVert = ");
      Serial.println(joyposVert);
      Serial.print("joyposHorz = ");
      Serial.println(joyposHorz);
      
--------

The receiver Serial monitor show this and then Freeze when I move the joystick

00:09:38.157 -> Driver available
00:09:38.194 -> joyposVert = 502
00:09:38.194 -> joyposHorz = 508
00:09:38.229 -> joyposVert = 502
00:09:38.229 -> joyposHorz = 508
00:09:38.267 -> joyposVert = 502
00:09:38.267 -> joyposHorz = 508
00:09:38.301 -> joyposVert = 502
00:09:38.335 -> joyposHorz =

So if someone could help me understand the way to do this I would very appreciate.

Thank you.

I kept searching and I found some answer to my problem after reading a post about pointers in C .(FreeCodeCamp 11 august 2020 by Srijan)

So now me sketch is able to read the data I sent with my Joystick but it still freezes after few seconds and I can't figure out a pattern.

The driver seems not available, I think so because i Add a serial print to see if it's available or not.

So my transmitter is sending Motorcontrol array [3]

And my receiver reconstruct the array and then the values are sent to the Ln298 H-Bridge motor.

This is my receiver code if anyone could help.

void loop()
{
  delay(100);
  if (rf_driver.available())
    Serial.println("Driver available");
    else
    Serial.println("Driver Stoped");
  {

    int buf[] = {0,0,0};
    uint8_t buflen = sizeof(buf);
    if (rf_driver.recv((uint8_t*)buf, &buflen)){
      
      for (int i = 0; i < 3; i++) {
        
        motorcontrol[0] = buf[0];
        motorcontrol[1] = buf[1];
        motorcontrol[2] = buf[2];

The problem I ran into seem's to be an memory overflow.

How can I solve this?

From the point where the data I am receiving is an array of 3 numbers ex: (255, 0, 0) should I use de realloc function and free it after?