Darrin Gray has never found a needle in a haystack. But he has found wedding rings lost in a corn pit, buried in a snowbank, dropped to the bottom of Lake Calhoun and hidden in a bag full of leaves.

Gray is a freelance wedding ring rescuer thanks to his hobby: He’s a metal detectorist.

The Waconia man is one of those guys (and, yes, they’re usually guys) you might see combing a beach, swinging a metal detector back and forth over the ground. His eyes are focused on the ground, but his ears are pricked inside headphones, listening for a telltale beep alerting him to a rare coin, precious jewelry, forgotten gangster loot or just a pull tab from an old pop can buried beneath his feet.

If it looks like a harmless if nerdy hobby for people who find croquet too fast-paced, maybe you haven’t heard of the metal detectorists who dive with scuba gear, searching for sunken treasure. Or those who have turned it into a competition, trying to be the fastest to speed-search a field full of buried dimes. Or those who help police investigations.

The sometimes secretive subculture — there are 900 members of the Metal Detecting Minnesota Facebook site — includes people who carve out a detecting niche, specializing in coins dropped on boulevards, valuables lost at the beach or artifacts unearthed at construction sites. They preach ethical metal detecting. They write songs about their adventures. And they reunite people with lost mementos.

Not everyone is a fan.

Archaeologists worry that hobbyists might damage historical sites. The activity is prohibited in Minnesota state parks and Three Rivers parks. Slate writer Emily Yoffe once called it “the world’s worst hobby — frustrating, solipsistic, potentially felonious.”

Even detectorists admit that they can appear a little weird, joking that their hobby is supported by losers.

But they’re just like the rest of us — except they never lost that childhood fascination with tales of buried treasure. Even if that treasure is just an old cigarette case, a long lost Little Orphan Annie ring or a forgotten Hot Wheels car.

“It’s the thrill of the hunt. It’s the find,” said Jason Roberge, a 46-year-old detectorist from Blaine.

“I love history. To hold that history, that’s been underground for so long, that’s something that’s important to me,” said the 52-year-old Gray, who has been detecting for more than 30 years.

“It’s kind of like the world’s biggest scratch-off ticket. You never know what’s out there,” said Andrew Brookman, a 38-year-old detectorist from Le Center, Minn.

For Bloomington resident Bruce Langbein, the hobby is therapy.

“You put the headphones on and you shut the world out,” said Langbein, 66.

After he returned from Vietnam in 1970 as a wounded infantryman, he became a hard drinker. He took up metal detecting because he needed something to do after he gave up alcohol. In the 31 years that he’s been looking for treasure, he estimates that he’s found more than 100,000 coins.

Ring-finding heroes

Sometimes, detectorists are heroes, reuniting heartbroken people with precious objects.

Take the case of newlywed Brittney McKittrick, who was sitting on a dock at Lake Calhoun in Minneapolis last October, fiddling with the wedding ring she had been wearing for just three months. Naturally, it fell off, dropped through a gap in the dock planks and disappeared into the lake. Her husband dove into the chilly water, but had no luck finding it.

So McKittrick turned to the internet.

“I just googled ‘finding a ring in a lake, help,’ ” she said.

Up came Gray on the Ring Finders (theringfinders.com) website, a listing of metal detectorists worldwide who offer to find missing items, usually in exchange for gas money and a voluntary reward.

A day later, Gray showed up at Calhoun, put on his wet suit and scuba gear and dove in with his waterproof metal detector while McKittrick parked his car.

By the time McKittrick got to the shore, Gray was done.

“As I walked over, he was coming back with the ring,” she said. “I was ecstatic.”

The Ring Finders website also led Patricia Kaufman to Mike Neiber, an Otsego metal detectorist, after Kaufman’s teenage son lost his iPhone in a snowbank last January in St. Paul.

“I was ready to write this off,” she said. “I was thinking, ‘We’ll never find this thing.’ ”

But Neiber, 34, located the phone, which still worked after being dried off and charged up.

“I jumped up and down and gave him a hug,” Kaufman said. She also gave him a $45 reward.

Chris Turner, who started the Ring Finders website in 2009, said metal detectorists also frequently help people recover rings by the roadside, thrown out of moving cars in the midst of lovers’ spats.

“This happens more than you think,” said Turner, of Vancouver.

He said his website includes almost 400 metal detectorists from 25 countries, who have recovered more than 3,400 rings. Turner has found more than 500 lost rings himself, as well as cellphones and, increasingly, car keys.

“The price of replacing keys is insane for some of these new cars. I’ve had people tear up when you find their keys,” he said.

The rewards he’s received have ranged from $2,000 to a loaf of banana bread.

Detective ‘dirt fishing’

When called for a recovery mission, detectorists often find that people have searched with a rented metal detector.

“I’ve gone to people’s backyards and there are holes everywhere,” Turner said.

But it takes experience to tell whether the beeping means a diamond ring or an old soda can tab.

“When you find someone’s ring, you get looks of absolute shock, joy and disbelief,” Neiber said. “People do not believe it will be found.”

Sometimes metal detectorists surprise themselves.

Last October, Neiber got a call to look for a wedding ring a woman lost when she capsized while kayaking on the Kinnickinnic River in western Wisconsin.

Wading in chest-deep water, with a strong current running, “I thought there was no way we’re going to get this ring,” Neiber said.

“I went to the spot where she tipped,” he said. “I held onto a branch. I got the signal. I scooped it up.”

Detectorists sometimes call their hobby “dirt fishing.” But it can involve a lot of detective work.

When Neiber searches for a lost ring, he’ll ask the owner which way she was standing when she threw the Frisbee, or whether she is lefthanded.

When they go hunting, detectorists study old maps and vintage postcards to find long forgotten ballparks, fairgrounds or beaches that might be promising.

Gray once used aerial photos to help find a lost $68,000 diamond ring dropped in a Wisconsin lake. (The insurance company that contacted him to do the search paid a reward of $19,600.)

Roberge gets permission to hunt old farmsteads, historic Girl Scout camps or former speakeasies.

“I like things that are old,” he said, calling century-old silver coins “cooler to me than finding a diamond ring.”

His favorite find? A 1789 George Washington inauguration button that he discovered on a trip to Massachusetts.

Nothing that old is likely to be found in Minnesota. That, and the fact that the ground is frozen solid here for much of the year, makes some local detectorists envious of the Colonial-era artifacts that can be found on the East Coast, the Saxon gold buried in England or the Spanish silver hidden in the Bahamas.

“If we find an Indian head penny, we’re doing pretty good,” Roberge said.

But others, including Reese Burnett of Woodbury, say Minnesota is a good place to practice the hobby because of the abundance of shoreline.

In the pre-air-conditioned early 20th century, Twin Cities lakes teemed with bathers who inevitably lost a lot of jewelry while frolicking in the water. Burnett, 56, estimates he’s found 35 gold rings in the past two years by wading the shores of St. Paul’s Lake Phalen.

He admitted he has some special techniques, learned from a mentor who found 120 gold rings in Lake McCarrons in Roseville.

“The faint signals is the key,” is all he would say.

Metal detecting can also be a competitive sport for people such as Jeff Kehl, who claims to be the fastest buried dime finder in the state.

The 54-year-old from Avon, Minn., is an ace at tournaments where a field is seeded with 500 silver dimes and dozens of competitors are turned loose to see who can find (and keep) the most coins in 30 minutes.

For memories, not money

Metal detectors cost from a few hundred dollars to a few thousand. Advances in technology have made the machines lighter, able to detect deeper in the ground and discriminate between types of metal.

The hobby has gotten a recent boost thanks to treasure hunting reality TV shows such as “Diggers” on the National Geographic Channel and “American Digger” on Spike TV. A critically praised BBC sitcom called “Detectorists,” which began airing in 2014, mines the quirkiness of the hobby for subtle humor.

You could also watch Roberge’s TreasureSeekerMN channel on YouTube, where the Blaine man documents discovering a silver half-dollar and yet another bottle cap.

Roberge even has written and recorded a metal detecting song that he uses as background music: “You might think I’m crazy/Well, heck I think it too/I’m going metal detecting now/’cause that’s just what I do.”

Archaeologists and anthropologists have expressed concerns about treasure hunting reality TV shows, saying they might encourage looting and destruction of protected historical sites.

But Minnesota detectorists say they advocate ethical detecting: searching only with permission, restoring the turf after they dig, and properly disposing of junk metal they unearth.

Gray and others also try to find an owner if there’s any identification on the objects they recover. After finding a lost 1950 St. Thomas Academy class ring and a 1944 class ring from Kimball, Minn., Gray tracked down the owners and got the rings back to them.

Amateur metal detectorists sometimes collaborate in authorized archaeological studies or help in crime investigations.

Kehl said members of his metal detecting club, the Minnkota Artifact Recovery Group, helped police search for the missing cellphone of Dru Sjodin, the University of North Dakota student who was kidnapped and killed in November 2003.

Detectorists also tempt one another with tales of buried loot and valuable coins.

The Gopher State Treasure Hunters, a Twin Cities group that meets once a month, gives out awards for the best jewelry or the most unusual object discovered.

A recent club newsletter recounted the story of Depression-era gangsters Ma Barker and Alvin Karpis, who supposedly buried $150,000 in ransom money in a canvas-wrapped metal box under a fence post in southern Minnesota.

“I hear stories of people burying money even to this day,” said Mike Parks, owner of Mission Metal Detector Sales in Coon Rapids.

Even if it’s not gold or silver, some metal detecting finds — Victorian-era dog license tags, early 20th-century retail tokens, even Jazz Age condom tins — can be sold to collectors.

But most detectorists aren’t in it for the money.

“I don’t really sell anything I find,” said Neiber, who has found almost 50 gold rings with unknown owners. “Each one is a little memory.

“I think it would take the fun out of doing it if it was kind of a monetary thing.”