University spokesman Grant Heston said normal campus operations resumed around noon after the makeshift devices were taken away from the dorm, which remained closed.
Authorities didn't immediately say what the student's intentions may have been.
"Obviously you never want somebody to commit suicide, but knowing what we know about what was in his room, we feel better at least that no one else was hurt," Heston said.
University police were called to the dorm around 12:20 a.m. after a fire alarm went off, Heston said. While they were on their way to the scene, a 911 call came in about a man with a gun.
Arriving officers found a man dead from what appeared to be a self-inflicted gunshot wound inside a residence at the Tower 1 dorm. Heston said the man was a student at the university.
Heston said the dorm has suites, with a main kitchen and living area, along with four bedrooms. The dead man was inside one of the rooms. Inside the room, Heston said, police also found what they described as an assault weapon, a handgun and makeshift explosive devices. Florida law prohibits the possession of guns on state university campuses.
He said the Orange County Sheriff's Office and the FBI are helping with the investigation. The sheriff's bomb squad was examining the explosive devices Monday morning.
About 500 students were evacuated from the dorm, and Heston said it would remain closed until authorities give an all-clear on the building.
On Monday morning, flashing signs around the campus alerted students and staff about the canceled classes. Campus shuttle buses were lined up about a half-mile from campus, with drivers standing by once the campus opens. The university's main campus in Orlando has about 51,000 students.
Antonio Whitehead, 21, a junior from Hollywood, Fla., said he heard the fire alarm go off after midnight and thought it was a routine alarm. He headed outside where he saw a crowd already heading across the street from the dorm.
"All of a sudden, I felt the crowd move a little faster. And a police officer with a machine gun or something told everyone to start moving a lot faster," he said.
Whitehead, who has lived in the dorm for two years, said the students were moved to an open area about 1,000 feet from UCF Arena. The area is a busy section of the campus, with restaurants and shops nearby.
Grant Hernandez, 20, a sophomore from Orlando who also is a resident at the dorm, said he woke up sometime after midnight when police were evacuating the building.
"We weren't allowed to get our cars. We weren't allowed to get our personal effects," Hernandez said.
"All we saw were people running, and they were not telling us what was going on," he added. "We were left unsure of things. It wasn't till about 6 o'clock that we got more information and a clearer picture of what was going on." He said officers on the scene began providing more information, and students checked updates on the university's website.
A statement there said the UCF Arena would open to accommodate displaced students. Counselors would be available to talk to students who need assistance.
The Tower 1 dorm is part of the school's popular Towers at Knight Plaza apartment building complex, according to UCF's website. Tower 1 has seven floors. The typical apartment layout has four bedroom and two bathrooms, the website says. Heston said the student who died had three roommates.
Associated Press writer Freida Frisaro in Miami contributed to this report.