my ipad nonstop will beep

for some reason my ipad has been constantley beeping the beeps aren't loud but they are long they ALWAYS happen, I even tried restarting my ipad and during the restart IT STILL beeped. I have yet to find out why this happens. Also somtimes it will beep when i turn it off it make the noise even as I write this. Another thing is that my ipad (asuming your home screen button is on your right) will always make the noise in a small hole to the left of my ipad.