浮点数转byte数组

  long a=;
  float b=34.56745f;
  float c=0.0;

   byte fbs[]={,,,};
   byte* t=fbs;
   float2Bytes(t,b);
   unsigned int addrF=(unsigned int) &b;
   unsigned int addrFc=(unsigned int) &c;

Serial.println(addrF);
  Serial.println(addrFc);
  float x= bytes2Float(fbs);

   for(int i=;i<;i++){
   byte bf1=*((byte*)(addrF + i));
   *((byte*)(addrFc + i))=bf1;
     Serial.print(bf1,HEX);
     if(i<)  Serial.print("-");
   }
   Serial.println(" ");

  for(int j=;j<;j++){
    Serial.print(fbs[j],HEX);
    if(j<)Serial.print("-");

  }
  Serial.println(" ");
  Serial.print("c:");
  Serial.println(c,);

  Serial.print("x:");
  Serial.println(x,);

  Serial.println(sizeof(b));

void float2Bytes(byte bytes_temp[],float float_variable){
  union {
    float a;
    byte bytes[];
  } thing;
  thing.a = float_variable;
  memcpy(bytes_temp, thing.bytes, );
}

float bytes2Float(byte bytes_temp[]){
  union {
    float a;
    byte bytes[];
  } thing;

  memcpy(thing.bytes,bytes_temp,  );
  return thing.a;
}

//查找字节数组中是否以指定的字符串开头
boolean bStartsWith(byte data[],int len, String fStr){
    int fLen=fStr.length() ;
   byte fBytes[fLen + ];
   fStr.getBytes(fBytes,fLen+);

   if(len<=)return false;
   if(len<fLen)return false;
   byte flag=;
   for(int j=;j<fLen;j++){
       if(fBytes[j]!=data[j])
       {
                flag=;
                break;
        }

    }
   if(flag) return true; 

   return false;
}

 void long2byte(unsigned long res,byte targets[] ) {
        targets[] = (byte) (res & 0xff);
        targets[] = (byte) ((res >> ) & 0xff);
        targets[] = (byte) ((res >> ) & 0xff);
        targets[] = (byte) (res >> );

    }  

unsigned long bytes2long(byte buf[]) {
        unsigned long firstByte = ;
        unsigned long secondByte = ;
        unsigned long thirdByte = ;
        unsigned long fourthByte = ;
        int index = ;
        firstByte = (0x000000FFU & ( buf[index+]));
        secondByte = (0x000000FFU & ( buf[index + ]));
        thirdByte = (0x000000FFU & ( buf[index + ]));
        fourthByte = (0x000000FFU & ( buf[index ]));
        index = index + ;
        return ((unsigned long) (firstByte <<  | secondByte <<  | thirdByte <<  | fourthByte)) & 0xFFFFFFFFUL;
    }  

int array[13];

int * addrArr=array; //数组可以看成int类型的地址

arduino 发送float类型数据

float b=(float)millis() / 1000.0;

Serial2.write( ((byte*) &b),4);
//Serial2.flush();
delay(100);