As a senior design project, the WaterDog is intended to show students' understanding of the principles of the engineering process and design planning/validation. By making use of skills in controls engineering, electrical engineering, mechanical engineer, and computer science, the WaterDog is the culmination of all that I leaned through our education at Purdue University. The project makes use of a Raspberry PI and USB webcam to track a colored tag through water, then controls a twin pair of brushless, waterproof motors to center the device overtop of the colored tag. The main structure of the device is PVC and acrylic - due to customer pricing limitations.

Using a camera positioned underneath the device in the water, the WaterDog can track divers with a colored tag affixed. The tag can be any color desired by the user, and tuned to track best in any environment. The tag is detected via custom software that identifies the tuned color, determines the tag's outline, and then identifies the centroid of the visible target. The software then determines a control signal that will most quickly close the distance between the WaterDog's center and the centroid of the target and applies it to the two brushless motors via two PWM-controlled ESCs. I was directly responsible for all the electronics and software systems used in this process.

To best protect divers, we had to be certain the WaterDog would not capsize while on the surface of the water, even in rough seas. The team developed "tri-stabilizer" concept to keep the craft afloat. Each "stabilizer" has a floatie on it - as the WaterDog tips in one direction, the buoyant force created by the other two stabilizers keep the device upright. Stabilizers are also easily removeable via a simple twist and pull, and the floaties can be inflated or deflated by the user for the smallest storage profile possible.

One of the most challenging parts of the WaterDog was sourcing components that would facilitate travel in water. After much research, it was determined that RC speedboat motors would work for this application. The twin motors are brushless and fully waterproof, controlled by two Electronic Speed Controllers (ESCs). The Raspberry Pi communicates with the ESCs via PWM, but there is no feedback mechanism. To ensure the WaterDog was moving straight, the two motors had to be tuned to run at the same speed. To prevent damage to the electronics, everything but the motors and camera are safely positioned in a waterproof box on the surface of the WaterDog.