In 2005–2006 while I was at Northern Virginia Community College, I started showing up at the George Mason University Robotics Club even though I wasn't a GMU student. The professor in charge was kind enough to let me hang out. Eventually they just gave me the door access code because I was pestering them too much. The club was building entries for the Trinity College Firefighting Competition. Its a simulated house miniature where the robot has to hear a smoke alarm go off, navigate through rooms, find a lit candle, and put it out.
I spent about a year building George. The chassis was Lego Technic with custom parts. The brain was an XPort Botball controller, which is a Game Boy Advance with a low-resolution camera that could do basic blob tracking. I wrote the firmware to do wall-following with ultrasonic sensors, switch to candle tracking when the camera locked on, and trigger the spray system.
Sprayers were salvaged from bug-spray bottles with a pneumatic reservoir half-filled with water and pressurized with an onboard pump, valve actuated by a servo. When the camera centered on the candle, the servo opened and the water shot out.
Qualification run, wall-follow, candle-lock, spray:
Camera tracking calibration test:
I never officially scored at Trinity. I broke George by accident before the scoring run. The qualification run was clean.
A few years later, a friend's dad saw the video of George and asked me to interview at his embedded-systems company, Hart Technologies. That interview is how my engineering career started.