A computer science student who unwittingly created an airport bomb scare by wearing a blinking circuit board attached to her shirt had a constitutional right to express herself in that manner, her lawyer argued Friday.

Attorney Thomas Dwyer Jr. asked a judge to throw out the charge against Star Simpson, 19, who is accused of possessing a hoax device.

East Boston District Court Judge Paul Mahoney took the motion to dismiss under advisement and said he would issue a ruling March 21.

Simpson, a Massachusetts Institute of Technology student from Lahaina, Hawaii, had gone to Logan International Airport last September to pick up her boyfriend.

She was held at gunpoint and arrested by state troopers after an alarm was raised over the battery-powered device on her shirt, which had flashing lights and the words "Socket to me" and "Course VI" (a major at MIT) written on the back.

Dwyer said his client, who is studying electrical engineering and computer science, did not think her shirt would scare anyone and has the right to free speech. He said she had worn it on campus without alarming anyone.

"People make these objects part of their identity. It's a part of their personal expression," he said. "They are legitimate forms of (constitutional) First Amendment expression."

Dwyer also argued that state law does not clearly define what a hoax device is. The charge carries a penalty of up to 2 1/2 years and a $5,000 fine.

Assistant District Attorney Stephen Kerr said that police officers who arrested Simpson determined that a reasonable person would think Simpson was wearing an infernal device, which includes bombs and other explosives.

The terminal was not evacuated and flights were not affected. But authorities expressed amazement that someone would wear the device to the airport where two of the jets hijacked in the Sept. 11 terrorist attacks took off.

Her lawyer said she disconnected the battery to the flashing lights after somebody at the airport told her she should not be wearing something like that.

Simpson, dressed in a long skirt and short-sleeved shirt, did not say anything during the court hearing.

Boston had been the focus of another bizarre security scare earlier last year when dozens of battery-powered devices were discovered around the city. They turned out to be a promotion for the Cartoon Network. Prosecutors dropped charges against two men after they apologized and performed community service.