Autonomous smart sentry gun
NOTE: This project is a work in progress. It can be easily modified to use airsoft or Nerf guns.
#Autonomous smart sentry gun plus
On the plus side, it prevents the center of gravity from moving as the tank empties over time. This removes some of the rotating mass from the gimbal setup, putting less strain on the servos, but moves the center of gravity forward, making the gun harder to balance in the beginning. I mounted the CO2 tank on one of the tripod legs, and used a hose to connect it to the actual gun. I used the SmartParts Ion, which you can get for pretty cheap on eBay. This battery is probably overkill for this project, but I liked it because it was the right dimensions to fit into the enclosure I chose, the right voltage to drive the regulator to 5V / 10A, and it has capacity and discharge rate to spare.
A target is the largest contiguous "blob" of changed pixels from one frame to the next (motion-based tracking).