*I don't wanna get all fussy and bring-down about home tinkering, but this is an unmanned, dirt-cheap, open-source, robot sniper rifle. I'm a little perturbed about the implications here. This is like building an IED that blasts nice soft marshmallows.
http://blog.makezine.com/archive/2010/05/arduino_nerf_sentry_gun_build_prima.html
*What the pros get up to:
https://www.wired.com/dangerroom/2010/05/israeli-microbot-fires-pencil-sized-rockets-to-stop-bombs/
*There's nothing about a device like this that inherently stops bombs. In the proper hands it could scamper about planting bombs.