Alone in a dark room, cartoons buzzing on his half-opened laptop, Nathaniel Troxel ’27, all 6-feet 4-inches and 200 pounds of him, sat painfully in bed and stared at his toughest opponent yet.
As a football tight end, he’d fearlessly trucked through linebackers and defensive backs, only to now be stymied by a new obstacle: his own door.
In 2023, then-high school senior Troxel was home in Katy, Texas, recovering from emergency surgery after a car wreck had left his femur “pointing the wrong way.”
Instead of looking forward to his first season at Trinity University, Troxel says that “the toughest thing I had to do all day was just getting through my door. I dreaded it. I wanted my independence back.”
Troxel got better and played for three years at Trinity before retiring. But he never forgot that feeling of losing his independence. Using his passion for entrepreneurship and backed by a well of Trinity talent, he’s now creating a solution for people facing the same challenge of accessibility.
Enter HandiDoor, a startup Troxel launched with football teammate Xadrian Huerta ’26, M’27 in 2024, that’s building a compact, mechanical door opener that you can click with a key fob that’s easy to attach to a walker, wheelchair, cane, or any other mobility device. After winning Trinity’s Louis H. Stumberg Venture Competition in 2025, the business has honed its mission toward serving individuals with limited mobility, helping them better retain their independence.
After adding two new Trinity faces to the team, the group is now on their third prototype, and the device has begun making trial rounds in the San Antonio retirement home circuit this summer. Troxel says HandiDoor just ran its first successful demo day at Morningside Ministries, which offers independent living, assisted-living, and other types of care for older adults, to rave reviews.
“The whole point of a door is what’s beyond,” Troxel says. “We’re so excited to show people what this device can do and what it’s going to let them do.”
New Openings
At Trinity, Troxel helped create openings on the practice field for teammate Huerta, a running back.
When the pair sat together in an “Entrepreneurial Mindset” class, Troxel pitched his teammate a vision for a remotely opened door.
“This was one of the first entrepreneurship classes I took at Trinity, and I originally had asked myself, ‘Why would anybody go to school for that?’” Troxel says. “But [in entrepreneurship classes] you learn to think in a problem-solution sense. I went from thinking about my problem to thinking about everyone who might have this problem.”
Huerta, who’d had his own experience with injuries, was sold. “I’ve been drawn to the idea of helping people for a long time,” he says. “This was just the opportunity to do it through Entrepreneurship.”
Teaching the class was Entrepreneurship Professor Matt Glazer, Trinity’s former entrepreneur-in-residence, who served as the pair’s first set of critical eyes and ears.
“My classes are a safe space for ideas and sometimes to tell students, ‘Your baby is ugly,’” Glazer says. “But that honesty also means that much more when I tell them that they’ve got something.”
In a sea of ideas for apps and AI-driven processes, Glazer was intrigued by Troxel and Huerta’s “unusual” desire to make a physical product, which reminded him of a previous Trinity startup’s success story.
“I will say that the two most successful student startups I ever had the chance to really know at Trinity work with hardware,” Glazer recalls. “One was Gavin [Buchanan ’20] with PatchRx, who was inspired by trying to fight the opioid crisis.”
Buchanan, along with co-founder Andrew Aertker ’21, sold PatchRx in a multimillion-dollar deal in 2025.
“And the second,” Glazer continues, “is going to be HandiDoor.”
Hinge, With a Pivot
Glazer thought Troxel and Huerta’s baby had enough Gerber-level potential to insist the pair enter it in Trinity’s Stumberg Competition in early 2025. The pair advanced through the spring preliminaries, then honed the business through the Center for Innovation and Entrepreneurship’s 10-week summer Trinity Incubator program.
The group connected with fundraising, mentoring, and consulting resources while taking crash courses in necessities like accounting, marketing, and talent acquisition, all supported by additional guidance from Trinity’s current Entrepreneur-in-Residence Matt Reedy ’79 and Entrepreneurship Professor John Burnam.
The group made two crucial pivots that summer. First, a mechanical problem.
“We wanted to have the mechanical hinge to the side of the door, not the bottom,” Troxel says. “But after testing, we realized the key fob was going to work better with the device at the base of the door.”
After solving the wireless link, the team also needed to make a better connection with their users, Troxel explains. And that meant learning the difference between a user and a customer.
“People who are retired, they might need this device but be reluctant to admit it,” Troxel says. “So really, after talking to our potential customers, we realized that we needed to market it to family members buying it for their parents, their aunts and uncles, their grandparents, not the users themselves.”
Now it was time to get better acquainted with their potential users. And Trinity’s location in San Antonio proved the perfect place to begin. About 13% of the city’s population is over 65, with that number expected to grow to 20% by 2040, according to a 2023 San Antonio Metropolitan District Health Study.
Troxel and his team decided to coordinate a visit to Morningside Ministries, which is just minutes away from Trinity’s campus.
There, Troxel learned more about his business than he ever would in a class.
“There were times when I stopped by Morningside for just a quick question, and I’d stay there for six hours, plus a happy hour, and really got to know the folks,” Troxel says. “They’ve lived so much and seen so many things through a different perspective, and that gives them experience where they’ll tell you stories all day long.”
With this change in perspective, Troxel and Huerta entered and won the finals of Stumberg, taking home a $45,000 grand prize. But this was just the beginning of the startup grind.
Trinity’s Team
Life after Stumberg hasn’t been glamorous.
As Troxel continued to wrestle with the device, Huerta took a part-time job at Nike and is still working toward a Master of Arts in Teaching at Trinity, thinking about perhaps becoming a football coach.
The pair needed help, specifically with marketing and engineering. “We needed to get the prototype functioning, and we needed to grow our awareness and get people wanting HandiDoor,” Huerta says.
Glazer encouraged the pair to draw upon one of San Antonio’s biggest talent pools: Trinity’s own campus.
“Trinity students are talented because they are interdisciplinary, yes, but they are also talented because the university has made so many affirmative choices to be welcoming,” Glazer says. “We have people from different countries, people who have been working since they were 14, people in sports, people who’ve faced big problems with their families. When I teach team formation, I teach about leveraging different experiences—if Nate had never been in that car accident, he would have never brought this idea to Xadrian.”
Tapping into this community, Troxel and Huerta found HandiDoor’s engineer, Tudor Constantinescu ’27.
Constantinescu has been taking things apart and putting them back together since he was 4, disassembling rotary phones in Măgurele, Romania. Growing up in a “science town” with a population of just 14,000 and a concentration of nine major research institutes, Constantinescu came to Trinity because he wanted a smaller engineering school that gave him a diverse, well-rounded look at the field.
“I feel like [HandiDoor] is doing something good for the world,” Constantinescu says. “That’s as important as any of its mechanics.”
As part of the team, Constantinescu focuses on ensuring the safety of the device. And he’s getting to apply what he’s learned in the classroom.
“I took a mechatronics class that really helped me understand, ‘Okay, this is how you make the plan, this is how you choose components, and this is how you make sure that they work together,’” Constantinescu says. “And now with HandiDoor, I get to take this overarching vision of taking a whole project from the beginning and seeing it through the end, which involves 3D printing, motors, and everything else that we’re doing.”
Yet, none of the tech matters if the startup can’t spread its message to the world. That’s where marketing major Alison Maass ’27 comes in.
The team decided to hire Maass after she struck up a conversation with Huerta in class.
Now, Maass is conducting website audits, creating marketing materials, managing social media posts, and leading user research for the team.
“I love being hands-on with the work in a way that goes beyond the classroom,” Maass says. “With HandiDoor, I get the chance to see the stuff I work on being put out in the world.”
Maass, like Troxel, especially cherishes her visits to the folks at Morningside.
“When we talk to the end users, we get to see how much of a difference this can make for them,” Maass says. “So, I think the biggest thing that I’ve discovered is that I love helping people. My work, as hard as it is, just becomes this great step to helping those people.”
Troxel and Huerta say their team is headed for big things, powered by this blend of technical ability and personal connection to their mission.
And those qualities, Huerta says, are embodied by the type of people Trinity opens doors for.
“Trinity does a really good job of recruiting students. Every person that I’ve come across on campus is very good at what they do, and they’re very smart,” he says. “But what’s really special is that everyone’s here with a purpose.”
Passing from one door to the next, Troxel is constantly finding new challenges. Yes, his prototype works, but the team now needs to figure out how to rely on more durable, easily manufactured parts.
Getting the product to market isn’t just about the bottom line.
Perhaps Troxel, tinkering with gears and Bluetooth connections, is thinking about the stories he’s heard at Morningside Ministries.
But he’s also thinking about his grandmothers: one who helped raise him after his father passed away, and the other who “loves to grow tulips up in Nebraska.”
Might they also be staring at a door with the same sense of dread that their grandson once did? With the click of a button, could the HandiDoor key fob help them hold onto their independence just a bit longer?
Now, alongside Huerta, Maass, and Constantinescu, that’s a door Troxel doesn’t have to open alone.