检测麦克风一击并做点什么

Question

我发现这个tutorial，它很好，但对我不起作用！

这里是代码：

- (void)listenForBlow:(NSTimer *)timer { 
    [recorder updateMeters]; 

    const double ALPHA = 0.05; 
    double peakPowerForChannel = pow(10, (0.05 * [recorder peakPowerForChannel:0])); 
    lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults; 

    if (lowPassResults > 0.95) 
     NSLog(@"Mic blow detected"); 
//change the background color e.g ! 
} 

控制台

告诉我的NSLog reseult像这样（没有任何保龄球！）：

2010-04-11 23:32:27.935 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:27.965 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:27.995 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.026 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.055 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.086 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.115 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.145 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.175 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.205 MicBlow[2358:207] Mic blow detected 
2010-04-11 23:32:28.236 MicBlow[2358:207] Mic blow detected 

我改变这个值：

if (lowPassResults < 0.95) 

至

if (lowPassResults > 0.95) 

所以它似乎工作！但不改变任何东西，再次如果我把背景更改代码，我的代码更改背景，但没有任何保龄球！ 有什么问题？

Answer 1

我也在使用它，它适用于我。您只需使用该值与lowPassResults进行比较即可。这是我的代码：

 
- (void)levelTimerCallback:(NSTimer *)timer { 
    [recorder updateMeters]; 

    const double ALPHA = 0.05; 
    double peakPowerForChannel = pow(10, (0.05 * [recorder peakPowerForChannel:0])); 
    lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults; 
    //NSLog(@"%f", lowPassResults); 
    if (lowPassResults > 0.55) 
     NSLog(@"Mic blow detected"); 
}