檢測麥克風一擊並做點什麼

Question

我發現這個tutorial，它很好，但對我不起作用！

這裏是代碼：

- (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 ! 
} 

控制檯

告訴我的NSLog reseult像這樣（沒有任何保齡球！）：

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 

我改變這個值：

if (lowPassResults < 0.95) 

至

if (lowPassResults > 0.95) 

所以它似乎工作！但不改變任何東西，再次如果我把背景更改代碼，我的代碼更改背景，但沒有任何保齡球！ 有什麼問題？

Answer 1

我也在使用它，它適用於我。您只需使用該值與lowPassResults進行比較即可。這是我的代碼：

 
- (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"); 
}