Arizona Daily Star, Benjie Sanders, Associated Press
Troy Tegeder plays with one of the app games he developed called Dino Digger with his daughter, Erica Tegeder in their home, Monday, Jan. 23, 2012 in Tucson, Ariz.

TUCSON, Ariz. — Looking for a career change? Vail resident Troy Tegeder has an app for that.

Just a few months ago, Tegeder was writing computer code for missiles by day, and hammering out code for mobile-device game applications by night.

Now, Tegeder has traded missiles for dinosaurs full time, thanks to a multibillion-dollar industry that didn't even exist a few years ago, and his own creativity and skill.

Tegeder, who quit his job as a Raytheon systems engineer in October after four years, has the top-selling paid kids' app on the Amazon App Store for Android.

The app, Dino Digger, allows users to digitally dig up a dinosaur's bones, put them together and manipulate a fully-fleshed digital dino. As of Monday, Dino Digger also was ranked 11th for sales among all paid apps, just behind a Scrabble app.

Tegeder's also had success with his first game, Shatter Ball, an all-ages ball-rolling game with a puzzle flair; Hungry Santa, a whimsical game in which players feed Santa to fatten him up; My Fairy Princess, an animated dress-up activity he wrote for his daughter; and BalloonMaker, a simple game for kids up to 2 years old that allows players to create and pop floating, multicolor balloons.

Raised in the Seattle area, Tegeder earned a bachelor's degree and a master's degree in engineering from Brigham Young University before joining Raytheon in March 2007.

A longtime artist as well as a programmer, Tegeder began fooling around with apps after buying an iPod Touch in 2009.

"To me, it was the perfect blend of engineering and art," said Tegeder, a gifted artist whose finely rendered pencil drawing of himself and his wife greets visitors in the couple's foyer.

Now he's part of a global mobile-apps industry that, after being spawned by Apple in mid-2008, has grown from $5.2 billion in sales in 2010 to an estimated $15 billion last year, according to the research firm Gartner.

Though he said he was leery of leaving his "great job" at Raytheon and had no issues with the company, he was determined to pursue his passion.

"I always wanted to run my own business, have my own little thing," Tegeder said.

Now, the time he spends at home with his two daughters - 4-year-old Erica and Sadie, nearly 2 - is meaningful in a new way.

"Erica, she's my director of research, Sadie's my quality-control tester," Tegeder said.

And he only half-jokingly introduces his wife, Nancee, an attorney specializing in estate planning, as the company lawyer.

Sure enough, during a reporter's visit, little Sadie taps away at BalloonMaker, deftly demonstrating on an iPad how she makes and pops the realistic-looking balloons, which always float upward.

By the time her dad starts answering a question about Dino Digger, Sadie's already tapped out of BalloonMaker and is ready to dig into Dino Digger. And she won't be 2 until next month.

It takes a lot of guts to quit a well-paying job with good benefits to follow what looks like a dotcom dream.

But it's worked out for Tegeder so far — on a good day, he's made up to four times his salary at Raytheon.

He declined to divulge exact dollar sales, which fluctuate widely day-to-day. But he said his daily downloads have ranged from 2,600 on the best day to 100 on the slowest.

Besides, his apps are available on the Apple App Store and Android Market. The apps cost $1.99 each, though they have been discounted to 99 cents at times; app stores generally take a 20 to 30 percent cut and pay the rest monthly.

Tegeder said he finally quit Raytheon when he projected his savings would last until his app sales matched his former salary. In two to three years, he projects making upwards of $200,000 in sales.

But he doesn't plan on becoming a millionaire overnight, and keeping his apps updated and adding more — he's working on an adult space-age shooter — is more than a full-time job.

"A lot of people look at this as a quick buck," he said. "(But) you have to make a quality app, and you have to spend a lot of time making them."

Information from: Arizona Daily Star,