I'm trying to use nRF24L01 module to send a messages between 2 arduinos
Transmiter code:
const char text[] = "Hello World";
radio.write(&text, sizeof(text));
delay(1000);
Reciver code:
char text[32] = {0};
radio.read(&text, sizeof(text));
Serial.println(text);
How I can put into char array an int value? I tried doing it in this way
For example: int a = 60; const char text[] = String(a); radio.write(&text, sizeof(text));
delay(1000);
Are you just looking for a way to get an arbitrary number expressed as a string? If so, you'll likely want to use some existing functions to help you along.
I recommend using sprintf
sprintf(char * str, char * format, args)
Where str is the string you're storing results in, format is the string you're inserting your values into for, you guessed it, formatting, and args are all the args, separated by commas, that you'll be passing into the format string to be inserted into the str string. An example might be:
char[x] result; //x is the number of elements in your array, atleast one for every letter and one for the end character, ex: "hello" needs 6.
int number = 24;
sprintf(result, "My number is %d", number);
sendSomewhere(result); //sends "My number is 24"
result. Also, if your “somewhere” inherits from Print (most things that implement write() do), then you can somewhere.print("My number is "); somewhere.print(24);.
– Edgar Bonet
Jul 8 '16 at 12:12
char[x] result; you probably mean char result[x];. 2) I understand the virtues of an open-ended answer, but using sprintf() instead of Print::print() will make the compiled program grow by 1 K or so. If the program already uses Print::print() (which is likely, since it is so common in Arduinoland), then the cost of sprintf() is more like 1.5 K.
– Edgar Bonet
Jul 9 '16 at 13:08
sprtintf() returns the length of the string created so you can do int length=sprintf(result, "My number is %d", number); radio.write(result, length); This saves using strlen() to calculate how many bytes to send.
– Andrew
Oct 7 '16 at 8:02
You can not have 'const' prefixed the 'text' variable as it then become 'read-only'.
char text[32];
int a = 60;
sprintf(text, "Number %d", a);
radio.write(&text, sizeof(text));
The simplest method is to send the integer in binary format (skipping the conversion to text).
int a = 60;
radio.write((char*) &a, sizeof(a));
Cheers!
radio.println(a)maybe? – Edgar Bonet Jul 7 '16 at 18:31