Hey guys! I'm very new to using Arduino and I for some reason thought it would be a good idea to try wireless communication...
Anyways, I am using the libraries and example code from here: GitHub - nRF24/RF24: OSI Layer 2 driver for nRF24L01 on Arduino & Raspberry Pi/Linux Devices
This seems to be VERY updated and is generally accepted as working. Now on to my issues. When I first attempted it, I installed the library and used the GettingStarted.ino class to test the wireless communication. I installed the class on both my Arduinos, only changing the radio number(was I supposed to do this?). I connected everything with this pinout: http://tmrh20.github.io/RF24/index.html - Scroll to bottom
Anyways, I wasn't able to get ANYTHING working at all. I connected everything correctly, double and triple checked, and opened the serial messages thingy. I was asked to type 't' to turn the Arduino into a transmit, but when I did this I got no response from the Arduino. The little RX lite did blink when I hit enter though. So I knew something was broken, but didn't know what. I was messing around with connections on the Arduino when I accidently put my finger under the chip, which literally made the serial communcation work. Well one, wtf just happened? And two, awesome. It looks like some pins are misplaced.
After checking the pins with the pin connections listed on the documentary, I was unable to fix the issue. So I got into the library code I was using and checked the pin listing there. I found that the MISO, MOSI, and SCK where all in the wrong place. I also found that when I changed it to comply the with code, it used up pin 8 which was where the CSN connection was. So I had to go into the code and change RF24 radio(7,8); to RF24 radio(11,12); This is all very confused and I'm sick so my brain isn't working right so I am having some trouble.
So with the updated library and code, I upload it to the chips again and make sure the connections are correct(Again, uploading one as radio 1 and one as radio 0)
The Serial output automatically started spewing when I connected the Arduino. It was spewing
Sent response 34340866
Sent response 34340866
Sent response 34340866
Sent response 34340866
Sent response 34340866
Sent response 34340866
Sent response 34340866
This meant it had a radio available and was set to receive. I concluded this behavior was undesired because it has a prompt when you start the serial comm, meaning that they probably want you to be able to actually read the prompt instead of being spammed. But typing 't' still worked. So I did. Then it started to spew, every second, this:
Sent 148283216, Got response 255, Round-trip delay 148282961 microseconds
Now sending
failed
Sent 149286452, Got response 255, Round-trip delay 149286197 microseconds
Now sending
failed
Sent 150289784, Got response 255, Round-trip delay 150289529 microseconds
Now sending
failed
Since 'failed' meant it wasn't able to write to the radio, I figured it didn't work. I also noticed that the round-trip delay increased in an oddly specific way(nearly 1000000 each iteration).
Anyways, yeah. Here was the code I was using to upload:
/*
* Getting Started example sketch for nRF24L01+ radios
* This is a very basic example of how to send data from one node to another
* Updated: Dec 2014 by TMRh20
*/
#include <SPI.h>
#include "RF24.h"
/****************** User Config ***************************/
/*** Set this radio as radio number 0 or 1 ***/
bool radioNumber = 1;
/* Hardware configuration: Set up nRF24L01 radio on SPI bus plus pins 7 & 8 */
RF24 radio(11,12);
/**********************************************************/
byte addresses[][6] = {"1Node","2Node"};
// Used to control whether this node is sending or receiving
bool role = 0;
void setup() {
Serial.begin(115200);
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]);
}
// Start the radio listening for data
radio.startListening();
}
void loop() {
/****************** Ping Out Role ***************************/
if (role == 1) {
radio.stopListening(); // First, stop listening so we can talk.
Serial.println(F("Now sending"));
unsigned long time = micros(); // Take the time, and send it. This will block until complete
if (!radio.write( &time, sizeof(unsigned long) )){
Serial.println(F("failed"));
}
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
radio.read( &got_time, sizeof(unsigned long) );
unsigned long time = micros();
// Spew it
Serial.print(F("Sent "));
Serial.print(time);
Serial.print(F(", Got response "));
Serial.print(got_time);
Serial.print(F(", Round-trip delay "));
Serial.print(time-got_time);
Serial.println(F(" microseconds"));
}
// Try again 1s later
delay(1000);
}
/****************** Pong Back Role ***************************/
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
So I wasn't able to get it working, yet. It's late now and I need a break. But tomorrow I will be figuring this out. I did realize while writing this I am using a 9 month old example, when the library was updated just a few months ago, so things may be broken. I noticed the another example 'CallResponse' was more recently updated, so I will be trying that tomorrow.
But has anyone else ran into these issues? Specifically the serial being frozen unless you basically short circuit the board? 
If so, how did you fix it? Like I said I am new to this but I am learning.
Thanks,
HeyAwesomePeople