Hello. Well after the 3rd time getting hit at work, this last time was major damage... of course no one said anything. I suspect that the issue is parking. The parking lot is a crappy design. Anyways, I built a bull bar for the rear bumper (its a truck) but I need some type of proximity device that will cover the sides. Especially the rear quarter panel of the truck bed. I would like a circuit that activates the truck horn when it detects an object within 3 feet. (I wonder if there is anyway to discriminate from people walking by?). Any ideas on a circuit? Thanks!