Thank you for your information!
I also tried DIY my guitar controller by myself: https://osdn.net/projects/dtxmania/wiki/%E3%82%B3%E3%83%B3%E3%83%88%E3%83%AD%E3%83%BC%E3%83%A9%E3%83%BC%E3%81%AE%E8%87%AA%E4%BD%9C (sorry japanese only)
To detect wailing certainly, I used gyro sensor instead of accelerometer. It's very helpful for me to know how to realize it by using accelerometer....