Troubles setting up a connection between 2 HC-SR04 sensors and nrf24L01 WiFi module, getting nan on Serial Monitor

Other Hardware Sensors
1

I am getting the "nan" message on the receiver serial monitor. I read that it shows when you declare non-number variable as float type. However, I cannot find the root cause of it and would like to see an explanation on it.
Here is the transmitter code:

#include <NewPing.h>
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
#define TRIGGER_PIN1 2
#define TRIGGER_PIN2 4
#define ECHO_PIN1 3
#define ECHO_PIN2 5
#define MAX_DISTANCE 400
float distance1;
float distance2;
RF24 radio(9,8);
const byte address[6]="00001";
const byte address1[6]="00002";
NewPing sonar1(TRIGGER_PIN1,ECHO_PIN1,MAX_DISTANCE);
NewPing sonar2(TRIGGER_PIN2,ECHO_PIN2,MAX_DISTANCE);
void setup()
{
  delay (1000);
  Serial.begin(9600);
  radio.begin();
  radio.openWritingPipe(address);
  radio.openWritingPipe(address1);
  radio.setPALevel(RF24_PA_MIN);
  radio.stopListening();
}

void loop()
{
  distance1=sonar1.ping_cm();
  distance2=sonar2.ping_cm();
  if (distance1>=400 || distance1<=0 && distance2>=400 || distance2<=0)
  {
    radio.write(&distance1, sizeof(distance1));
    radio.write(&distance2, sizeof(distance2));
    delay(1000);
  }
}

And here is the receiver:

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
RF24 radio(9,8);
const byte address[6]="00001";
const byte address1[6]="00002";
float distance1;
float distance2;
void setup()
{
  delay(1000);
  Serial.begin(9600);
  radio.begin();
  radio.openReadingPipe(1, address);
  radio.openReadingPipe(1, address1);
  radio.setPALevel(RF24_PA_MIN);
  radio.startListening();
}
void loop()
{
  if (radio.available())
  {
    while(radio.available())
    {
      radio.read(&distance1, sizeof(distance1));
      radio.read(&distance2, sizeof(distance2));
      Serial.println(distance1);
      Serial.println(distance2);
    }
  }
  delay(1000);
}

What I am trying to get is two ultrasonic sensors to get distance on the TX Arduino in a sort of a X, Y coordination for a working machine which should move in X and Y coordinates. I need the ultrasonic sensors to get the distance data and send it to the receiver, which will later be saved on an SD. But I first need to straighten this problem with the "nan". Thank you, and all help is welcomed

2

Welcome to the forum

Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'

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3

WHY are you only sending when the data is out of range?

4

I wonder if this is doing what you think it is doing, too:

Since && has precedence over ||, it will be evaluated like this:

Note the parens around distance1<=0 && distance2>=400

Don't know anything about your project, but that seems weird. Maybe it doesn't matter.