Sending a int using VirtualWire

Community General Discussions
1

I've got the basic examples reciever and transmitter working sending the default "hello" message.

But I really want to send a int, for example 45 or another value over RF links. Can't understand how to rewrite it to do so!

 

Anyone care to help me out?

 

Reciever code:

 

#include <VirtualWire.h>

#undef int

#undef abs

#undef double

#undef float

#undef round

void setup()

{

    Serial.begin(9600); // Debugging only

    Serial.println("setup");

 

    // Initialise the IO and ISR

    vw_set_ptt_inverted(true); // Required for DR3100

    vw_setup(2000); // Bits per sec

 

    vw_rx_start();       // Start the receiver PLL running

}

 

void loop()

{

    uint8_t buf[VW_MAX_MESSAGE_LEN];

    uint8_t buflen = VW_MAX_MESSAGE_LEN;

 

    if (vw_get_message(buf, &buflen)) // Non-blocking

    {

int i;

 

        digitalWrite(13, true); // Flash a light to show received good message

// Message with a good checksum received, dump it.

Serial.print("Got: ");

for (i = 0; i < buflen; i++)

{

   Serial.print(buf[i], HEX);

   Serial.print(" ");

}

Serial.println("");

        digitalWrite(13, false);

    }

}

 

 

 

Transmitter code:

 

#include <VirtualWire.h>

#undef int

#undef abs

#undef double

#undef float

#undef round

void setup()

{

    Serial.begin(9600);  // Debugging only

    Serial.println("setup");

 

    // Initialise the IO and ISR

    vw_set_ptt_inverted(true); // Required for DR3100

    vw_setup(2000); // Bits per sec

}

 

void loop()

{

    const char *msg = "hello";

 

    digitalWrite(13, true); // Flash a light to show transmitting

    vw_send((uint8_t *)msg, strlen(msg));

    vw_wait_tx(); // Wait until the whole message is gone

    digitalWrite(13, false);

    delay(200);

}

 

2

look up the functions atoi()

look up the functions atoi() and itoa() - they convert between strings and ints

I am curious about VirtualWire -  are there benefits over using NewSoftSerial ? I have been using nss mostly because I kept seeing it recommended on the Arduino board.

3

Ah, could you show me a

Ah, could you show me a example code? for just sending one number.

4

** I am not at the computer**

 

I am not at the computer with the Arduino IDE, so this is somewhat approximate…

int iVal = 45; // or whatever value you want to send

char acInt[6];

itoa( iVal, acInt, 10);

// acInt is now a string representation of the number 45 - pass it instead of the Hello World string

the other way:

int iVal = atoi( acStr); // acStr is your input buffer

 

that just makes ints into string and visa versa. In practice, you will need something to indicate that it is a number, so maybe you would put an X in front of it like this:

char acInt[7];

acInt[0] = ‘X’;

itoa( iVal, &acInt[1], 10);

and then send it and on the receive side do something like:

if( acStr[0] == ‘X’)

{

int iVal = atoi( &acStr[1]); // acStr is your input buffer

}
Strings are just arrays of characters. Parsing through them is tedious but not difficult if you get the basic concepts.