First off, I love your style here. It gives a rustic, after-apocolypse feel to the work. The only flaw I see is that the word 'HANGAR' on the hologram seems to be backwards. I don't know if that was intended, but the robot would have to read it like that. The lighting also seems a bit off. I think a blue highlight in the appropriate places would show the viewers that the hologram is made of blue light. Your use of brushes is great, though. The brushes blend together nicely, and seem to be in the right places. It's almost impossible to tell that this is a digital piece of art and not a photograph, at first glance.
The use of colour gives a good atmosphere to the drawing. The dull browns, yellows, and greys in the background help give the aforementioned rustic feel, and they are contrasted by the bright blues of the hologram. The character uses a mix of these colours, which really gives an idea of his purpose and when he was created. If you were going for a more futuristic feel, as I'm guessing you were, you could have used more blue and white, instead of yellow and brown. Though that would have been a bit stereotypical of the sci-fi, futuristic image. And the image would have blended a little too easily. So, if you took all this into consideration, good job. If not, kudos for being able to make it happen without thinking about it.
Overall, this is a good idea that was translated perfectly. It's definately going into my favourites. Maybe I will be inspired by it someday.