433 MHZ connection between two Arduino (nano,uno) fails after some time The goal of this part of my project is to establish a wireless connection between an Arduino nano and an Arduino uno. For this I use 433 MHZ receiver and sender. The nano sends, the uno receives and prints. I have working code and the connection works and I can send, receive and print my message.
But at some point the Uno receives just a part of the message and after this point always receives (or prints) just this part of the message:

 

Nano (sender):

#include &lt;VirtualWire.h&gt; 
char *msg = "123456789123456789";


It is not always 2 digits, sometimes more are received.

I searched for errors. The nano is constantly sending and the uno flips to not receiving the whole message. So I reupload the code to the uno without modification and it works again for a few seconds/minutes, so I guess it's a problem at the receiving end.

Here is my code:

Sender(nano):

#include &lt;VirtualWire.h&gt;
char *msg = "123456789123456789"

void setup()   {
 Serial.begin(9600);

 pinMode(7,OUTPUT);
 pinMode(5,OUTPUT);
 digitalWrite(5,LOW); //GND
 pinMode(6,OUTPUT)
 digitalWrite(6,HIGH); //5V
 vw_setup(5000);
 vw_set_tx_pin(7);
}

void loop()     {
 vw_send((uint8_t*)msg, strlen(msg));
 vw_wait_tx();
 delay(500);
}


Receiver(Uno):

#include &lt;VirtualWire.h&gt;

int i;
uint8_t buf[VW_MAX_MESSAGE_LEN];
uint8_t buflen = VW_MAX_MESSAGE_LEN;

void setup() {

 Serial.begin(9600);
 pinMode(5,INPUT);
 pinMode(6,INPUT); // two data inputs, we use just one
 pinMode(7,OUTPUT);
 digitalWrite(7,LOW); //GND
 pinMode(4,OUTPUT);
 digitalWrite(4,HIGH); // 5V VCC
 vw_setup(5000);
 vw_set_rx_pin(6);
 vw_rx_start();
 Serial.println("Starting up");

}

void loop() {

 if(vw_get_message(buf,&amp;buflen)) {
   for(i=0;i&lt;buflen; i++) {
    Serial.print((char)buf[i]);
   }
 }
}


It doesn't happen after a certain time or number of messages. I have no clue what could be the problem.

Thanks in advance,
Niklas

Edit: Problem seems solved. Changing bitrate from 5000 to 2000 solved the problem, but I don't actually know why.
Regarding the hardware problem, there are some advices in the comments.
As you wrote, the solution is to reduce the bitrate at 2000 bps.

The remaining question is why the receiver always truncates the message (after a receiving error occurs). The answer is in the definition of the buflen parameter of the vw_get_message function. The page https://www.pjrc.com/teensy/td_libs_VirtualWire.html says:


  "buflen" should have the array's maximum size upon input, and upon return the number of bytes actually copied is retured.


Therefore, when a transmission error occurs, the buflen variable returns a smaller number to inform you how many characters are received. If you do not reset the buflen variable to VW_MAX_MESSAGE_LEN before calling vw_get_message again, you are telling the library that you expect a smaller number of characters and the function respects that size (thinking that you have a smaller buffer).

In other words, if you want try to receive the full message after a transmission error occured, set the buflen variable to VW_MAX_MESSAGE_LEN before each call of the vw_get_message function.