Short film, distopian future, desert, steampunk leg, giant invisible robots

Im trying to find ou the title for a short film, i remember seeing it around 2008 - 2012 about a crippled man from a leg that uses a steampunk contraption attached to his leg to help him walk, he is walking on a desert canyon when suddenly gets ambushed by a group of robbers, he manage to fight some of them with his cane, his contraption gets mangled and he need to recharge it with some liquid, but at some point one of the thugs activates a device that the old man drops, this electronic device activates an invisible giant robot, this mountain size figure seems to be attracted to the electronic device. At the end of the short its revealed that the thugs that activates the device was a woman, and many years later this woman is telling her son the story of the old man.
Thanks in advance to anyone that can help me find this short


It reminded me of this series of sci fi shorts, one of them being very similar