nrl24l01每次只能发送4个字节，前面说到，第一个字节用于源节点，第二个字节用于目的节点。因此只剩下两个字节用于温度和湿度，一个字节只有八位，需要表示温湿度的正负数，因此每个字节的第一位表示正负符号，后七位表示数据，最大能表示+-127。
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; // RPi generic: 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 = 0;//receive 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=0x01; unsigned long srchead=0x00000000; 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.openReadingPipe(1,pipes); /***********************************/ // This simple sketch opens two pipes for these two nodes to communicate // back and forth. radio.startListening(); //cout << "Listening .... "; int node = atoi(argv[1]); //cout << "Listening Node is : " <<node<<" "; while(1){ unsigned long end_time = millis(); if(radio.available()){ radio.read(&receData,sizeof(unsigned long)); //cout<<"receData is: "<<receData<<" "; unsigned int check = (unsigned int) receData>>24; unsigned long data = receData & 0x0000ffff; //cout<<"check is "<<check<<" "; if(check==node && (receData & 0x00ff0000)==srchead){ //cout<<"Get Node oriData: "<<receData<<",data:"<<data<<",Time consume "<<(end_time-start_time)<<"ms "; int temperature = (data & 0x00007f00)>>8; int humidity = data & 0x0000007f; if((0x00008000& data)==0){ temperature = -temperature; } if((0x00000080&data)==0){ humidity = -humidity; } cout<<temperature<<"-"<<humidity<<" ";//温度-湿度 break; } } //cout<<"time out is "<<(end_time-start_time)<<" "; if((end_time-start_time)>=5000){ cout<<"Wait Data from Node "<<node<<" time out "; break; } } return 0; }
Arduino Leonardo代码
如下：
#include <SPI.h> #include "RF24.h" #include <SPI.h> #include "RF24.h" #include <printf.h> #include <dht.h> dht DHT; #define DHT22_PIN 7 /****************** 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){ int chk = DHT.read22(DHT22_PIN); //读取数据 if(chk==DHTLIB_OK){ int humidity = (int)(DHT.humidity+0.5); int temperature = (int)(DHT.temperature+0.5); Serial.print("data:temperature="); Serial.print(temperature); Serial.print(",humidity="); Serial.println(humidity); //第三个字节存放温度，第四个字节存放湿度，目前只能表示 unsigned long data = (temperature<<8)+(humidity)+(srchead<<24)+(deshead<<16); if(temperature>0){ data = data+0x00008000; } if(humidity>0){ data = data+0x00000080; } Serial.print("Sending:"); Serial.println(data); 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