I Want To Make A Biped, That W

I want to make a biped, that would be like a roaming sentry, you could set it out at night, and it could march around in your yard, scanning for intruders, and it would have some 410 gauge barrels machined, one on each shoulder, and they could have dragons breath specialty rounds loaded, in case their is a dangerous situation, and need for defense, or maybe just a mini flame thrower.