He wasn’t ready Friday afternoon to trade his traditional wooden violin for the plastic one a team of University of Toledo engineering students had 3D-printed, but Merwin Siu was still impressed.

“It’s really promising,” said Mr. Siu, the principal second violin at the Toledo Symphony Orchestra. “It could use a couple of little tweaks, but it’s definitely got a lot going for it.”

Radi Hamoudeh, a UT senior from Perrysburg who spoke about the four-student team’s project, acknowledged improvements still need to be made, but said the progress so far proves “a more affordable violin for beginners” is practical.

At $120, the printed version costs less than one quarter the typical price of a basic violin, Mr. Hamoudeh said. The “main difficulty,” he said, is making round tuning pegs, important to maintaining proper pitch, using 3D printing.

Mr. Hamoudeh and teammates Alex Keenan, of Genoa, Ohio, Jacob Munshower, of Cleveland, and Timothy Dawson, of Parma, Ohio, were among scores of UT engineering students who put their senior projects on display Friday in several ground-floor corridors at Nitschke Hall.

The Senior Design Expo is required for graduation from UT’s College of Engineering, and the 338 students participating this time came from all of its disciplines, including computer sciences and electrical, chemical, civil, mechanical, industrial, and biomedical engineering.

“Students showcase their creativity and ingenuity as they tackle real-life challenges, in some cases collaborating with local businesses, industries, and federal agencies,” the university said in a statement.

Concepts ranged from devices designed to help people with disabilities, such as an automated screw-cap bottle opener, to systems to address common problems, such as pairing a facial-recognition system with vehicle automation to let the automation take over if a driver nods off behind the wheel.

Darshan Guruparan, a Malaysian student on that design team, said it was inspired by a friend of his who nodded off for just a moment while driving back to Toledo from Cedar Point, found himself at the edge of the road when he came to, and overcorrected causing a crash. While there were no injuries, the vehicle was totaled.

The system, co-developed by Sanskar Lamsal, of Nepal, and Unmesh Khamolkar and Jay Alikkal, both from India, goes beyond warning a driver when it detects droopy eyes: It signals to the vehicle’s autonomy system to take over.

Mr. Guruparan said the next research phase is to build in how control returns to the driver, but it won’t be right away. A driver regaining consciousness, he said, would need at least a few seconds to process the situation in a way that doesn’t lead to overcorrection.

While three of that team’s members still have their spring semesters to complete, a University of Toledo statement said Mr. Alikkal will graduate later this month and already has a job with Honda as a software engineer.

Mr. Siu said the printed-violin project was advanced by Alain Trudel, the symphony’s music director, who “has been very interested in environmentally sustainable violins.

“We saw this opportunity with the UT senior design program to get some great young minds focused on a really unusual problem,” the violinist said.

The problem that students Greg Roth, of Edgerton, Hannah Spillett, of Holland, and Addisyn Umbel, of Olmsted Falls, Ohio, chose to tackle, meanwhile, was better security for prescription medications against the risk of in-home theft or accidental use.

They proposed a fingerprint reader electrically connected to a locking clamp on pill bottles.

“It’s not designed to be the Fort Knox of protecting your medications,” Mr. Roth said, but it will keep one’s children or grandchildren from getting past supposedly childproof caps and prevent “crimes of opportunity” when guests in a home might pinch a few opioid pills from the medicine cabinet.

At another table, Julia Hatfield, of Monroe, Lauren Peraino, of Macomb, Mich., and Adelaide White, of Warren, Ohio, offered a sensor-equipped headband designed to warn people with visual impairments about obstacles their heads might hit, such as low-hanging tree branches or low-mounted signs.

“It gives different types of pulses, depending on the proximity of the obstacle,” Ms. Hatfield explained.

The foursome of Brian Armstrong, of Walbridge, Frank Collins, of Toledo, Logan Halloran, of Monclova, and Jacob Tyner, of Ann Arbor, set out to develop an indoor version of the food-delivery robots now seen on some college campuses.

Their Hallway Navigation Robot uses light detection and ranging (lidar) to maintain a set distance from hallway walls, radio chips to identify stopping places, and cellular app technology for direction to deliver whatever is placed in a plastic bin to a designated location.

Their display said it was intended to replace “the challenges of the human element” in a hotel room-service setting, although they had yet to incorporate an elevator interface to make deliveries to an upstairs floor.

Mr. Armstrong noted also that while it worked well in development, the large volume of people using cell phones during the Senior Design Expo seemed to be interfering with its radio signal.

Two teams, meanwhile, developed mechanical drink-can crushers, intended to facilitate aluminum recycling without the need for either a proper place in one’s home to stomp empties or the aim and balance necessary to get a compact result.

And then there was the mechanical engineering quartet of Ben Swihart, of LaPorte, Ind., Sam Weller, of Holland, Nicholas Rodd, of Dundee, Mich., and Tyler Rollins, of North Olmsted, Ohio, who devised a solution for a table gamers’ niche: a machine to dispense and roll multiple dice of different sizes.

In games like Dungeons & Dragons, Mr. Swihart explained, “you need to roll a lot of dice,” and it can take a while sometimes to dig the precise combination required to produce the directed probability of outcomes. Their 3D-printed machine can dispense dice of five common sizes – the smaller ones requiring a plastic insert – and as many of them as it is told to roll.

The devices also can be helpful for people playing games with dice who have poor manual dexterity, Mr. Weller said.

The one common die it couldn’t handle is the four-sided version, which tended to jam against each other in the chute, they said. And the prototype was not designed to select and roll dice of different sizes at the same time, so separate copies would be needed for each die size in use for the game.

First Published December 8, 2023, 11:33 p.m.