树莓派与Arduino Leonardo使用NRF24L01无线模块通信之基于RF24库 (五) 树莓派单子节点发送数据

本项目中各个节点和树莓派的通信不区分信道，因此如果由树莓派发送给特定节点的数据会被所有节点接收到，因此子节点可以判别该数据是否发给自己的，需要在数据的第二个字节中加入目标节点的编号（第一个字节为源节点的编号）。

设计思路：基于前面提到的两个节点进行双工通信，树莓派不断的向节点发送数据，为了保证数据发送可以到达，持续发送100ms。

树莓派代码

如下：

#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>
#include <RF24/RF24.h>

using namespace std;

RF24 radio(22,0,BCM2835_SPI_SPEED_8MHZ);


/********** User Config *********/
// Assign a unique identifier for this node, 0 or 1
bool radioNumber = 1;
bool role = 1;//send mode
unsigned long  start_time=millis();
unsigned long count=0;
/********************************/

// Radio pipe addresses for the 2 nodes to communicate.
const uint64_t pipes = 0xE8E8F0F0E1LL;

unsigned long  receData;
unsigned long  respData=27;
unsigned long  srchead=0x00000000;
unsigned long  deshead=0x00010000;
int main(int argc, char** argv){

  cout << "RF24/examples/GettingStarted/
";

  // Setup and configure rf radio
  radio.begin();
  // optionally, increase the delay between retries & # of retries
  radio.setRetries(15,15);
  // Dump the configuration of the rf unit for debugging
  radio.printDetails();
  
  radio.openWritingPipe(pipes);
/***********************************/
  // This simple sketch opens two pipes for these two nodes to communicate
  // back and forth.

  radio.stopListening();

  cout << "Listening .... 
";

  int node = atoi(argv[1]);
  int value = atoi(argv[2]);
  cout<<"Node is :"<<node<<",value is "<<value<<" .
";
  // forever loop
  while (1)
  {
  // Pong back role.  Receive each packet, dump it out, and send it back
  //
        unsigned long data = respData +srchead+deshead;
        radio.write(&data,sizeof(unsigned long));
        printf("Send Data:size(%d),%lu 
",sizeof(unsigned long),data);
        role = 0;
        //radio.startListening();
        unsigned long end_time = millis();
        if((end_time-start_time)>=1000){
            break;
        }

  } // forever loop

  return 0;
}

输入指令：sudo ./send_once 1 14,1表示节点号，14表示输入给节点的值。结果如下：

Arduino Leonardo代码

如下：

#include <SPI.h>
#include "RF24.h"
#include <SPI.h>
#include "RF24.h"
#include <printf.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(9,10);
/**********************************************************/

byte addresses[][6] = {"1Node","2Node"};

// Used to control whether this node is sending or receiving
bool role = 1;//1表示发送模式，0表示接收模式
unsigned long start_time = millis();

//这个是我们即将建立的传输渠道编码
//!!要和另一个模块的一致
const uint64_t pipes = 0xE8E8F0F0E1LL;
 
//这个变量会保持我们接受到的信息
//变量类型一定要和传过来的一样
//要传输的数据
unsigned long sendData = 15;
unsigned long srchead = 0x01;//高16位为头标志，前8位为源节点，后8位为目的节点。根据标志不同区分不同发送源，00为中心主节点
unsigned long deshead = 0x00;//高16位为头标志，前8位为源节点，后8位为目的节点。根据标志不同区分不同发送源，00为中心主节点
unsigned long receData;

void setup() {
  pinMode(13,OUTPUT);//指示灯
  Serial.begin(57600);
  printf_begin();
  Serial.println(F("RF24/examples/GettingStarted"));
  
  radio.begin();

  radio.setPALevel(RF24_PA_MAX);
  radio.openWritingPipe(pipes);
  
}

void loop() {
   Serial.print("role:");
   Serial.println(role);
  if(role){
     unsigned long data = sendData+(srchead<<24)+(deshead<<16);
     Serial.print("Sending:");
     Serial.println(sendData);
     digitalWrite(13,HIGH);
     bool ok = radio.write(&data,sizeof(unsigned long));

     
       role = 0; 
       radio.openReadingPipe(1,pipes);
       radio.startListening();
       start_time = millis();
     
  }
  if(!role){
     digitalWrite(13,LOW);
     if(radio.available()){
         radio.read(&receData,sizeof(unsigned long));
        
         //根据目标节点，判断是否是发给自己的，如果是，执行相关操作
         unsigned long check = (receData & 0x00ff0000)>>16;

         if(check == srchead){
            //接收到来自主机的数据，执行相关操作
             Serial.print("Response:");
             Serial.println(receData&0x0000ffff);
             Serial.println("=======================");
             sendData++;
         }
         role = 1;
         radio.stopListening();
     }else{
        unsigned long end_time = millis();
        if((end_time-start_time)>=100){
          role = 1;
          radio.stopListening();
          radio.openWritingPipe(pipes);
        }
     }
  }
  
} // Loop