title: Controlling voltage supply on usb port using c or any programming language
body: <p>I don't have much konwledge in electronics. i wanted to turn on/off led connected to usb port using program. usb port consists 4 line (data+,data-,voltage ,ground) if i connect voltage and ground lines to led , it will glow. i've been searching on internet this issue and i find that it is not possible to control led connected to usb using program because supply over datapin is too low which can not be used to tun on off led.</p>
  
  <p>but what if i connect my led to vol and ground pin and control the entire power supply of usb port , i guess it is possible to control led using program. there is a way to disable and enable power supply over usb port.</p>
  
  <p>i also want to know is it bad to follow this approach. does it damage usb controller to frequently enable/disable power supply.</p>
  
  <pre><code>Algo :
  
        a = Get_input_from_user() ;
        if(a=="ON")
             turn power supply of usb port ON.
            else
             turn power supply of usb port OFF.
  </code></pre>
  
  <p>this thing is certainly possible using extra hardwares, i don't  want to use any extra hardware.</p>