The Poly boys figured they had the "petite slalom" all sewn up when their robot was the only one to clear the first heat without jostling any cones - in a blistering 18 seconds.
Likewise, last year's "mystery course" champions from Hereford High School were predicting an easy repeat victory - a full hour before the secret course was unveiled.
"I'm pretty sure we're going to win," said Justin Zelinsky, 15, with a shrug, as he plunked a pair of infrared sensors into his car-like "bot."
Happily for the competition - and their nervous parents and coaches - the day had in store thrilling upsets, spectacular crashes, even disqualification for illegal robot enhancements.
More than 30 middle and high school students representing about 10 schools faced off yesterday in the second Robotic Systems Challenge at the Johns Hopkins University.
"Our goal is to entice middle and high school students to become interested in the sciences, because the numbers of students enrolling is very low right now," said Cyndi Ramey, education director of the Computer Integrated Surgical Systems and Technology division at Hopkins, whose students organized the competition.
Before the games began, Daniel Creasy, assistant admissions director at Hopkins, assured the pre-college crowd they would have a leg up in admissions to elite colleges such as his if they plan to pursue engineering-related studies.
The contest required student contestants to program and assemble unmanned vehicles called "boe-bots," which are self-contained rolling-robot kits often used in classrooms.
In addition to the slalom and maze contest, there was also a "robotic brain tumor surgery" challenge - designed to mimic a nanotechnological medical application - in which students programmed bots to detect colored spots (tumors) in an enclosed space (brain).
Most of the contestants were high school boys, reflecting the gender imbalance in engineering, but some female contestants said the event encouraged them to pursue the sciences.
"I feel like I belong here, really," said Becky Vickers, an eighth-grader from Dumbarton Middle School. "Everybody is nice and they include you, and if you don't understand something they explain it to you and don't make you feel dumb."
The atmosphere in Hopkins' Glass Pavilion started out calm yesterday morning, with groups of students quietly assembling robots and putting finishing touches on programs via laptops.
But things heated up quickly, beginning with the slalom event.
"The slalom course depends on 'dead reckoning,'" explained Chip DiBerardino, a robotics engineer with General Dynamics, whose son is on the Hereford team. "That means the robot is driving a preprogrammed course without sensing its environment. The problem is, small errors add up."
Solomon Ajetunmobi, 15, and George Dinglas, 15, of Baltimore's Polytechnic Institute discovered that lesson quickly. Their seemingly ingenious use of diagonal patterns - which helped them breeze through the first, simple slalom - caused their bot to veer wildly off-course in the second, more challenging heat.
The most hotly contested event was the so-called mystery course, in which the robot had to rely on sensors to navigate a previously unseen maze-plus-obstacle course.
Some bots were outfitted with infrared sensors to detect walls and various course hazards; others relied on metal "whiskers" that brushed up against barriers. But all had problems.
Many robots flipped over, became stuck in corners or simply spun in place. The judges gave all the teams extra time to refine their code, adjust their sensors and brainstorm.
In the end, only the robot from Chopticon High School in St. Mary's County successfully reached the end of the course, but it was disqualified for being equipped with a bumper-like sensor that is not part of the boe-bot's basic package.
Ultimately, teams from the Park School in Brooklandville won the most points in both the mystery course and slalom events, while another Chopticon squad took the top spot - and the digital camera prize - in the brain tumor hunt.
Even if they didn't win, the competition and camaraderie seemed to overcome some of their discomfort with being regarded as budding nerdy engineers.
"This is the complete opposite of what we normally do," insisted Poly's Ajetunmobi early in the day.
"Yeah, we play sports," added his teammate, Dinglas. Both are members of the school's undefeated lacrosse team.
But after the scores were tallied and the Poly boys joined their fellow bot-heads in a pizza lunch, attitudes had mellowed somewhat. "It was challenge, and it brought out a different side of me," said Ajetunmobi. "I met some cool people."