Jot Test

RobotShop · October 26, 2013, 2:00pm

UPDATE: Progress on NRF24L01 code for working between PC, Hub, and Robot.

So, here is my attempt at a swarmie build. Not much here yet, simply a personal build log until I get an iteration cheap enough, then, I'll start incorporating them into the Overlord project.

I have to bow to Bajdi; those little NRF24L01 take a lot more brainpower than simple ole' Bluetooth. I tried for some time to write my own code that would send and receive bytes to or from the other node. After a little of hair pulling I gave up and started reading other's code. I came across Robvio on the Arduino Forums who had some rather nifty code that I left nearly intact.

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
RF24 radio(8,7);

// Radio pipe addresses for the 2 nodes to communicate.

const uint64_t pipes[2] = {0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };
//for Serial input

String inputString = “”;         // a string to hold incoming data

boolean stringComplete = false;  // whether the string is complete
//NRF Packages

byte SendPackage[32];

byte ReceivePackage[32];

boolean sending=0;
void setup(void)

{

//

// Print preamble

//
Serial.begin(9600);

radio.begin();

// optionally, increase the delay between retries & # of retries

radio.setRetries(15,15);

radio.setPayloadSize(32);

radio.openWritingPipe(pipes[1]);

radio.openReadingPipe(1,pipes[0]);

radio.startListening();

//radio.printDetails();

}
void loop(void)

{

//check for NRF received

NRFreceive();

//check for Serial received (or filled by NRF)

Serialreceive();

}
void serialEvent() {

Serial.println(“Event”);

while (Serial.available()) {

char inChar = (char)Serial.read();

inputString += inChar;

if (inChar == ‘\n’) {

stringComplete = true;

}

}

}
byte NRFsend(String NRFPack = “”){

NRFPack.getBytes(SendPackage, 32);

radio.stopListening();

radio.openWritingPipe(pipes[0]);

radio.openReadingPipe(1,pipes[1]);

bool ok = radio.write(SendPackage,sizeof(SendPackage));

if (!ok) Serial.println(“NRFerror”);

radio.startListening();

unsigned long started_waiting_at = millis();

bool timeout = false;

while ( ! radio.available() && ! timeout )

if (millis() - started_waiting_at > 200 )

timeout = true;

if ( timeout )

{

Serial.println(“NRFerror”);

}

radio.openWritingPipe(pipes[1]);

radio.openReadingPipe(1,pipes[0]);

}
void NRFreceive(){

if ( radio.available() )

{

//byte ReceivePackage[32];

bool done = false;

while (!done)

{

done = radio.read( &ReceivePackage, sizeof(ReceivePackage) );

delay(5);

}

radio.stopListening();

inputString = ((char *)ReceivePackage);

stringComplete = true;

radio.write( “1”, 1 );

radio.startListening();

}

}
void Serialreceive(){
if (stringComplete) {

if (inputString.startsWith(“T:”)) {

NRFsend(inputString.substring(2));

}

if (inputString.startsWith(“S:”)) {

Serial.print(inputString.substring(2));

}
inputString <span style="color: #333333;">=</span> <span style="background-color: #fff0f0;">""</span>;
stringComplete <span style="color: #333333;">=</span> <span style="color: #007020;">false</span>;

}

}

The way this code works is much like a software and serial simulated Bluetooth module.

To send serial data it goes like this, you type something with a prefix code, T for transmit and S for serial print, and ending with a newline character (\n).

For example, typing the following in the terminal on module A:

T:S: My message \n

Will send “My message” to the other module B, then, it will print “My Message” to serial line on the module B.

If you type,

T: My message \n

This will transmit “My message” from module A to module B, but it will not be printed to the serial line on module B.

I’ll let you guys look the code over and tell me if I can improve it for what I’m doing. Right now, I’ve tested it with some basic Python code to send a serial message to my hub (Arduino Uno and NRF24L01), which relays it to the robot (Arduino Pro Mini and NRF24L01).