sudo add-apt-repository ppa:nilarimogard/webupd8 sudo apt-get update sudo apt-get install ap-hotspot
Then configure it as
sudo ap-hotspot configure
It will asks for interfaces, Access point name(which can be anything you want to see as wifi_hotspot name), password(which is your wifi_hotspot security key).
Now, if you able to configure successfully and dont get any kind of Unsupported wifi errors(if you get that simply means, your wifi_card doesnt support infrastrucutre Access point wifi_hotspot, so can do nothing on it), then procceed.
So just now start your hotspot as
sudo ap-hotspot start
If you want to stop then
sudo ap-hotspot stop
If you wanna see all available commands