Hunched over a laptop, Earl and Josh Sharpe watch codes flow in from a 2016 Volkswagen GTI.

Amid the roar of machinery at the Modern Automotive Performance warehouse in Cottage Grove, the Minnesota cousins play around with different car functions, like unlocking its doors or turning its engine off.

Once they identify which operation each code is responsible for, they can move on to their next task: hacking the car.

"The first step is snooping," Josh Sharpe explains. "The next step is injecting your own message to make it go faster, or whatever you want it to do."

Car hacking — or auto tinkering — involves tweaking codes to get desired features, such as side-view mirrors that swoosh in when approaching walls, or doors that unlock via one's cellphone.

Josh and Earl have made waves in the niche community with their new company, called Macchina, and their M2 device. This spring, they raised more than $141,000 on Kickstarter, which included preselling hundreds of the devices.

The open source hardware tool helps users trick a car's computers into agreeing with different coding. Industry veterans praise the M2 for its ability to work with a variety of programming frameworks.

"It lets you tinker with your car in a way that nothing has before. It's really exciting," said Josh Mickolio, product manager at Digi-Key Corp., which helped market the M2. "We're very impressed with it." The M2's roots can be traced to a dead 1997 Ford Contour that Josh Sharpe received from his grandpa in 2006. With some of his engineering buddies, he revived it by building a small computer that tricked it to recognize an electric motor.

"We figured out the hardware you need to do that is very general-purpose, whether you're doing hot rodding or mechanics for diagnostics. At the core, it's the same automotive standards," Earl said.

As the two made refinements to the device, they started selling ­versions of it online. But they didn't actively market a polished product until this year.

"It happened so slowly, we never noticed," Earl said.

The gears to start a real business started turning once they received hundreds of responses to their post on the social media site Reddit offering leftover, earlier versions of the device. So many people wanted one that they turned it into a contest, doling them out to those who had the best ideas.

Days before launching Kickstarter, the two set their fundraising goal at $25,000. By the end of the month, they had outsold themselves by more than $100,000.

They recruited workers, including some family and friends, to help package devices and manage social media as they fielded thousands of questions.

Customers ranged from academics, aspiring engineers, hobbyists and security researchers. In addition, several businesses expressed interest in selling or using the M2 for their own products.

The Kickstarter campaign included multiple levels for various versions of the M2 or merchandise. An early bird special featured a $69 price tag. For $99, customers received a beta version and are to report back what they've accomplished with it and any kinks they've encountered. And for $79, customers will receive the M2, along with any adjustments from the beta developers, in July.

The pay-to-test idea comes from tech giants, like Google and ­Amazon, Earl said.

"It's a really good process," said Rob Faludi of Digi International, which is not related to Digi-Key but is also helping to market the M2. "With the maker market, you need to get it in users' hands because … once your product gets out into the real world, people start doing things you didn't expect."

For Macchina, some of those things have included creating a button that turns off the gas engine in a Chevy Volt. Beta testers on Macchina's forums are also kicking around ideas like using the M2 to add a recording setting to cars with cameras.

Each car has different possibilities. Industry experts say the device's flexibility to work with different programming frameworks, as well as its ability to communicate with wireless devices, makes it stand out among other devices for car hacking.

"I think it will be influential," ­Faludi said. "All those things together in one package really gives people in the maker community a lot of choices about how they interact with these systems and how they would want to build it."

Craig Smith, research director of transportation security at Rapid7, a data and analytics-based cyber security software company, said he's interested to see if the M2 can lead to a standard way to communicate with a variety of networks inside cars. If so, he said, the device could lead to people coming out with some of their own inventions.

"We're excited about the M2 because it has the chance of making that standard, so we don't have to worry so much about the hardware or how to communicate with it, we can just focus on what it does," he said.

Earl and Josh liken car hacking to hot rodding, the mechanical customizing of cars made popular in the '50s. But with increasingly computerized cars, they said, the hobby has shifted from working with screwdrivers and wrenches to unlocking codes and writing new ones.

Not everyone equates hot rodding with car hacking. Most large car companies claim that fiddling with their vehicles' software coding counts as copyright infringement. But in 2015, the Librarian of Congress created an exemption to the Digital Millennium Copyright Act, legalizing most auto tinkering.

Some forms of tinkering, like creating devices that give users access to software codes, still fall into a legal gray area. On the other hand, the exemption allows toolmakers to access software codes themselves, which lets them make devices that help users tweak their cars without seeing the coding, said Electronic Frontier Foundation attorney Kit Walsh.

Since the exemption became active in 2016, car hackers have been emboldened to share their work, leading to a growing community, Smith said.

"We're seeing more people come forward with this stuff," he said. "And so there's a movement to be more open and share it."

The exemption will be up for debate again in 2018, during the next review process. Walsh and other advocates hope to use stories like the Sharpes' when they present to the Librarian of Congress.

"It's a good time to use those rights. It's like a muscle, you have to use it to keep it strong," Walsh said.

Most of the collaboration takes place remotely, with hobbyists sharing their progress online and tweaking open source software and hardware. Right now, many of the 100 M2 beta testers are brainstorming on Macchina's online forums.

"The idea of getting a bunch of people working a similar project together, all over the world, is pretty cool," Josh said. "There's all these different perspectives and it results in transportation that is safer, more fun and more secure."

Jackie Renzetti is a University of Minnesota student on assignment for the Star Tribune.