#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>
/****************** User Config ***************************/
/*** Set this radio as radio number 0 or 1 ***/
bool radioNumber = 0;
/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(7, 8);
/**********************************************************/
byte addresses[][6] = {"1Node","2Node"};
// Used to control whether this node is sending or receiving
bool role = 1;
void setup() {
Serial.begin(9600);
Serial.println(F("RF24/examples/GettingStarted"));
Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));
radio.begin();
// Set the PA Level low to prevent power supply related issues since this is a
// getting_started sketch, and the likelihood of close proximity of the devices. RF24_PA_MAX is default.
radio.setPALevel(RF24_PA_LOW);
// Open a writing and reading pipe on each radio, with opposite addresses
if(radioNumber){
radio.openWritingPipe(addresses[1]);
radio.openReadingPipe(1,addresses[0]);
}else{
radio.openWritingPipe(addresses[0]);
radio.openReadingPipe(1,addresses[1]);
}
radio.setDataRate(RF24_2MBPS);
// Start the radio listening for data
radio.startListening();
}
void loop() {
/****************** Ping Out Role T ***************************/
if (role == 1) {
radio.stopListening(); // First, stop listening so we can talk.
Serial.println(F("----------------------------------------------"));
Serial.println(F("Now sending Data"));
unsigned long start_time = micros();
String Astart_time = "HELP"; // Take the time, and send it. This will block until complete
if (!radio.write( &Astart_time, sizeof(Astart_time) ))
{
Serial.println(F("Write failed"));
}
else
{
Serial.println(F("**** Write SUCCEEDED ****"));
}
radio.startListening(); // Now, continue listening
unsigned long started_waiting_at = micros(); // Set up a timeout period, get the current microseconds
boolean timeout = false; // Set up a variable to indicate if a response was received or not
while ( ! radio.available() ) // While nothing is received
{
if (micros() - started_waiting_at > 200000 ) // If waited longer than 200ms, indicate timeout and exit while loop
{
timeout = true;
break;
}
}
if ( timeout )
{ // Describe the results
Serial.println(F("Failed, response timed out."));
}else
{
unsigned long got_time; // Grab the response, compare, and send to debugging spew
String Agot_time;
radio.read( &Agot_time, sizeof(got_time) );
unsigned long end_time = micros();
// Spew it
Serial.print(F("Tx: "));
Serial.println(Astart_time);
Serial.print(F("Rx: "));
Serial.println(Agot_time);
Serial.print(F("Round-trip delay "));
Serial.print(end_time-start_time);
Serial.println(F(" micros"));
Serial.println("");
}
// Try again 1s later
delay(1000);
}
/****************** Pong Back Role R ***************************/
if ( role == 0 )
{
unsigned long got_time;
if( radio.available()){ // Variable for the received timestamp
while (radio.available())
{ // While there is data ready
radio.read( &got_time, sizeof(unsigned long) ); // Get the payload
}
radio.stopListening(); // First, stop listening so we can talk
radio.write( &got_time, sizeof(unsigned long) ); // Send the final one back.
radio.startListening(); // Now, resume listening so we catch the next packets.
Serial.print(F("Sent response "));
Serial.println(got_time);
}
}
/****************** Change Roles via Serial Commands ***************************/
if ( Serial.available() )
{
char c = toupper(Serial.read());
if ( c == 'T' && role == 0 ){
Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK"));
role = 1; // Become the primary transmitter (ping out)
}else
if ( c == 'R' && role == 1 ){
Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK"));
role = 0; // Become the primary receiver (pong back)
radio.startListening();
}
}
} // Loop