How can I use adk Library
<p>I'm new to android and trying to learn hardware interaction in android </p>

<ol>
<li>have to root to install driver of hardware. </li>
<li>can I use adk library for custom hardware development.</li>
</ol>

<p>As shown <a href="http://developer.android.com/guide/topics/connectivity/usb/index.html" rel="nofollow">here</a>, 
if using accessory mode, then <strong>accessory must power the bus.</strong>
But as specified <a href="http://source.android.com/tech/accessories/guide/custom.html" rel="nofollow">here</a>, 
<strong>accessory can be anything as keyboard too.</strong>
So i got confused: how can a keyboard power the bus?</p>

<p>Please help me out.</p>
