家居智能系統中通常要使用紅外遙控去控制各種家電，如：電視、機頂盒、空調、電風扇等，家電往往分布在家庭的各個不同房間，而紅外信號是無法穿墻去控制家電，怎么樣讓紅外信號“穿墻”，這是所有智能家居系統必須解決的問題。
我的解決方案是使用NRF24L01無線通信模塊來進行紅外信號“穿墻”，基本思路是：在家居智能主機上插上一片NRF24L01，而紅外穿墻控制分機同樣裝有NRF24L01，分機的功能是用于接收主機主機發來的紅外遙控信號，并將這個信號通過分機上的紅外發光二極管發送出去。
我們采集到的紅外遙控信號是一個時間序列，保存在一個uint16_t的數組中，這個數組根據遙控信號不同，從長度為幾十到幾百不等，比如美的遙控信號的時間序列通常在200個左右。而NRF24L01每次能夠可靠傳輸的數據包最大是32個字節，要通過它傳輸幾百個字節的數據才能解決紅外信號穿墻的問題，為此我設計了一個簡單的流式傳輸協議來通過NRF24L01進行可靠數據的傳輸，相應的函數原型：
uint8_t NRF24L01_Send(uint8_t *buf, uint16_t len);
uint16_t NRF24L01_Recv(uint8_t *buf, uint16_t len);
由于這兩個函數傳輸的是uint8_t的數組，而紅外信號的時間序列是uint16_t的數組，為了將信號通過無線模塊進行傳輸，我還特地設計了兩個轉換函數：
void word2ByteArray(uint16_t *buf, uint16_t len, uint8_t *bBuf);
void byte2WordArray(uint8_t *bBuf, uint16_t bLen, uint16_t *buf);
有了上述一些基礎準備，接下來實現紅外穿墻控制就水到渠成了。
為了驗證我的這個方案，特地設計了一個模擬的家居智能“主機”，這個主機功能非常簡單：接收來自串口的輸入，如果串口輸入1，則向分機發送開空調的紅外信號，讓隔壁的空調打開；如果輸入0，則向分機發送關空調的紅外信號，讓隔壁的空調關機。在軟件包的“Projects\NRF24L01-SendLong”文件夾包含了這個程序的完整工程，可以直接編譯、燒寫和調試。程序代碼如下：
#include "WProgram.h"
#include "24l01.h"
#include "stdlib_ex.h"
//美的空調：開
uint16_t rawData_1[] =
{4486,4428,590,1604,590,534,563,1605,591,1603,592,533,563,535,563,1604,591,535,563,534,564,1606,589,
534,563,535,563,1604,590,1603,592,535,563,1604,591,1607,588,535,563,1605,590,1607,588,1604,591,1632,
564,1602,593,1605,591,534,563,1602,593,534,563,534,563,534,563,535,563,534,563,534,563,1604,591,534,
563,1632,563,534,564,1604,590,1605,590,534,563,534,564,534,563,1605,591,533,563,1604,591,535,563,534,
563,1605,590,1604,592,5263,4512,4427,592,1602,593,534,563,1602,593,1632,563,535,563,534,563,1605,
590,535,564,533,563,1607,589,534,563,534,563,1604,592,1602,593,534,563,1604,591,1630,564,534,563,
1631,564,1604,591,1604,592,1603,592,1604,591,1633,563,534,563,1604,592,534,563,535,563,510,587,534,
563,534,564,510,587,1630,565,510,587,1631,564,511,586,1603,592,1604,591,511,587,511,587,509,588,1605,
590,510,587,1603,593,510,587,511,587,1603,592,1604,591};
//美的空調：關
uint16_t rawData_0[] =
{4464,4451,567,1628,567,532,565,1628,567,1629,567,531,565,532,567,1626,568,531,566,532,565,1628,568,
532,565,532,566,1627,568,1630,565,532,566,1627,568,532,566,1629,566,1628,567,1629,567,1628,567,532,
565,1629,567,1627,568,1628,567,531,567,531,565,532,566,532,565,1627,568,531,566,532,566,1628,567,
1629,566,1627,568,533,565,532,565,532,566,531,566,532,566,531,565,533,565,532,565,1627,568,1629,567,
1629,567,1628,567,1627,568,5286,4489,4452,567,1629,566,532,566,1628,568,1627,568,531,566,531,566,
1628,568,530,566,531,565,1629,567,532,565,532,565,1630,566,1629,567,532,565,1628,567,533,565,1629,
567,1628,567,1628,592,1604,590,508,577,1616,577,1620,590,1603,567,533,589,508,589,509,589,508,589,
1603,592,508,590,507,590,1603,591,1633,562,1543,652,509,589,509,588,509,589,508,590,508,589,508,590,
507,589,508,589,1605,590,1604,591,1604,591,1604,592,1604,592};
uint16_t len1 = sizeof(rawData_1)/sizeof(uint16_t);
uint16_t len0 = sizeof(rawData_0)/sizeof(uint16_t);
void setup()
{
//初始化Rainbow
boardInit();
//初始化默認串口
Serial.begin();
//初始化無線通信模塊
NRF24L01_Init();
Serial.println("NRF24L01-SendLong start...");
}
void loop()
{
uint8_t *bRawData;
if(Serial.available())
{
switch(Serial.read())
{
case 0x30:
bRawData = new uint8_t[2*len0];
word2ByteArray(rawData_0, len0, bRawData);
//關空調
if(NRF24L01_Send(bRawData, 2*len0))
Serial.println("Close conditioner...");
delete []bRawData;
break;
case 0x31:
bRawData = new uint8_t[2*len1];
word2ByteArray(rawData_1, len1, bRawData);
//開空調
if(NRF24L01_Send(bRawData, 2*len1))
Serial.println("Open conditioner...");
delete []bRawData;
break;
}
}
}
int main()
{
setup();
while(1) loop();
}
紅外信號穿墻控制分機的功能則非常簡單，僅僅就是接收NRF24L01發來的紅外遙控時間序列，然后通過紅外發光二極管發送出去。在軟件包的“Projects\NRF24L01-RecvLong”文件夾包含了紅外穿墻分機的完整工程，可以直接編譯、燒寫和調試。程序代碼如下：
#include "WProgram.h"
#include "24l01.h"
#include "stdlib_ex.h"
#include "IRRemote.h"
//接收緩沖的大小
#define RECV_BUF_LEN 800
uint8_t buf[RECV_BUF_LEN];
//定義紅外發射對象，紅外發光二極管接到TIM2的CH1，即：PB8
IRSend irSend;
void setup()
{
//初始化Rainbow
boardInit();
//初始化默認串口
Serial.begin();
//初始化無線通信模塊
NRF24L01_Init();
//用38K的載波進行調制
irSend.enableIROut(38);
Serial.println("NRF24L01-RecvLong start...");
}
void loop()
{
//接收到對方發來的數據
uint16_t wBuf[RECV_BUF_LEN/2];
uint16_t len = NRF24L01_Recv(buf, RECV_BUF_LEN);
if(len > 0)
{
//收到的byte數組，轉化成紅外遙控的uint16_t數組
byte2WordArray(buf, len, wBuf);
irSend.sendRaw(wBuf, len/2);
}
}
int main()
{
setup();
while(1) loop();
}