Gary Alvarez’s science-fiction shrine — a daughter’s bedroom repurposed when she left for college — has a familiar centerpiece.

For nearly three years, Alvarez has been working on a life-size replica of R2-D2, the playful droid hero of the “Star Wars” franchises. Alvarez says the little guy is a hit when he takes him out in public.

“You have little kids who haven’t seen “Star Wars,” but they see R2 and they start running toward him,” he said. “It’s a little give-back for the kids. We do this for the love of it. It’s a way to bring joy to the kids who are out there.”

Alvarez belongs to the Southern R2 Builders Group, a loosely connected handful of “Star Wars” fanatics from the southeast U.S. who build replicas of R2-D2 and other droids from the franchise for fun.

The robots consist of a number of materials. Alvarez, for instance, used two Arduino electronic units, which are open-source programmable hardware that allows users to create and control actions through smartphones. The Arduinos are embedded in formed fiberglass, along with wood portions and some metal pieces.

Others repurpose remote-controlled car electronics for the effects they seek.

For Chip Luck, building an R2-D2 had been a lifelong dream since he watched the first film in 1977 — seven times. He finally finished his first droid during the mid-1990s.

Ever since, he says, he has poured about $15,000 into the endeavor.

He helped create the Southern R2 Builders Group, pushing the group from its first four members to one that now includes 70 to 80 people.

Group members say R2’s independence and persistence helped make the droid one of the more popular “Star Wars” characters.

“Whether he was right or wrong, R2 would get things done, even if he was told not to do it,” said Todd Bixby, 56, who has also started a replica of BB-8, the soccer ball-looking drone in the new film. “I have always been one that wouldn’t just follow the easy road, so (R2-D2) clicked with me.”

Alvarez’s “Star Wars” fandom extends beyond the droid, however. In his sci-fi shrine, Alvarez also has a Darth Vader model — decked out for the season with a Santa Claus hat — standing in the doorway, along with “Star Wars” posters and plaques along the walls. In addition, items such as pillows, figurines and a Pez dispenser dot the room to represent R2-D2, a hero who helped the main characters of the blockbuster out of several tight spots.

Dozens of R2 builder groups exist across the U.S. and the world.

To varying degrees, the clubs welcome those new to robots alongside lifelong engineers who have perfected the method of building R2 units.

With the series returning last week and opening with an estimated $120.5 million from Thursday night previews and opening day Friday, Walt Disney Co. told Associated Press — which smashes the previous opening day record of $91.1 million, set by 2011’s “Harry Potter and the Deathly Hallows, Part 2.” — interest in the space western film franchise has spiked once again.

For the club’s members, it means renewed interest and more invites from local conferences to show off the droids. As the new movie opened Thursday in Orlando, Southern R2 Builders Group members headed to local theaters with droids and costumes at hand.

Luck even had an Anakin Skywalker costume lined up for his theater-going attire.

“Most of us are geeks who are engineers,” he said. “I’m 58 going on 15. It just keeps us young. It also fulfills my lifelong dream of being a part of the “Star Wars” universe.”