F.A.C.T. Turret Team 9 Anthony Ragghianti David Fixter Danny Smith Jack Hunt Joseph Potter

Problem Statement Original Version: - Write a vision-processing program for the Matlab programming environment capable of calculating the location of the center of a color blob from real-time video. This program will be used to construct an automated object tracking paintball turret that would track a person and fire paintballs at them under specified conditions. Powerpoint-friendly Version: - Build a paintball gun that finds targets and shoots at them automatically.

Rejected Idea #1 Siege Engine - It would be either a catapult or a trebuchet - It would launch a payload or a team member - It would be bloody cool. Rejected because… - No one really wanted to be launched - Actually hitting our intended target (which was certainly not the stadium) may have had legal consequences

Rejected Idea #2 Potato Cannon - It would be self-loading or bolt-action. - It would have a clip of several potatoes for faster loading. - It would fire either automatically or semi-automatically. - It would be bloody cool. Rejected because… - So many people build potato cannons - The modifications would have been difficult

Final Solution – The F.A.C.T. Turret Webcam - Mounted on gun platform and aligned with barrel Vision Processing in Matlab - Analyzes video input to determine target Lego Mindstorm Motors - To turn gun platform - To operate trigger

F.A.C.T. Turret Schematic

Matlab Program Polls camera for real-time picture Determines all pixels of tracked color in each picture Calculates the centroid of the color blob Sends outputs to RCX depending on horizontal position of centroid to center color blob.

Communicating with Mindstorm Motors Robotics Invention System - Programmed RCX to continuously monitor the IR tower - Accepted three different numerical outputs from Matlab - Activates the two turning motors and changes direction based on output - Activates a gearbox to pull the trigger if target is centered

Construction Tripod and Platform - Used a video camera tripod with two plywood platforms Lego Motors and Wheels - Mounted on lower platform Trigger-firing Mechanism - Used Lego pieces to build a gear reduction system to increase the motor’s torque enough to pull the trigger

Testing and Problems The actual construction went smoothly, but we had several problems related to communication between different components - The RCX at first refused to accept any signals from Matlab - The RCX would often read the signal as 0, due to an obscure bug in our Matlab program The weight of the gun and other components caused the upper platform to warp - This caused a periodic loss of contact with one of the drive motors - When we replaced the platform, everything had to be re-measured, which was time-consuming

Conclusions Given time, even projects which sound nearly impossible can be made to work. The most difficult part of a complex project is system integration; getting all the components to work together. Matlab conceals unlimited power. Quality and accuracy in construction makes systems much more reliable. Work is easier when you enjoy it.