Sandra Mueller always told her daughters that their father, Mike Dillon, was a lot of things. But he was never boring.

He was a tinkerer, with a four-car garage in their Richfield home that was packed with junk and tools — he referred to it as the girls’ dowry. He had a passion for full-size Jeep vehicles, the older the better. He was an inventor of computer chips for difficult environments, like space and engines. His name is on 17 patents.

And he was funny, in the kind of dry way typical of physics majors, Mueller said.

“People say they are not funny, but you just don’t get their jokes,” she said.

Dillon, 53, died April 25 after a monthlong battle with pancreatic cancer. He often seemed like a gruff, unapproachable person on the surface, but underneath he was a softy, Mueller said.

“When the kids’ hamster was dying he was the one who held it and stroked it,” she said.

Dillon and Mueller grew up in Salt Lake City. He developed his fascination for tinkering from his father, who was a physician, but who also loved engineering. To their mother’s great amusement, Dillon and his brother took apart the family washing machine, but left the door off. They sometimes accidentally set fires in the house, and became proud of their ability to put them out before the fire trucks arrived, Mueller said.

Mueller first met him while sharing a chemistry lab assignment in high school.

“He would not do the lab we were supposed to do,” she said. “I followed the rules and he did not.”

They started dating in college, and when Mueller came to the University of Minnesota for graduate school in chemistry, Dillon followed her. He went to the physics department just before the semester began and asked if he could join the program.

They said sure, as long as he could teach labs.

He earned degrees in physics and electrical engineering, and after graduate school started designing security systems. Dillon then moved to Unisys Corp. to work on Navy computers and an air traffic control system.

That’s where he first met the group of fellow semiconductor designers who would stick together for the next 20 years through three companies.

“It’s a pretty cool synergy,” Mueller said.

For the past 15 years the group worked as a team at Silicon Space Technologies, an Austin, Texas-based company that makes computer chips for extreme conditions like heat and radiation.

“Everyone loves their iPhone, but you can’t take it with you into space,” said Scott Peterson, one of the designers in Dillon’s group and vice president of design and development for the company. Dillon was good at the basic design of the chips, how the transistors and wires connect. Over the years, he and others in the group came up with enough new ideas to warrant 17 patents, most of them related to new techniques to make the chips or to make them function better, Peterson said.

“He was a character,” Peterson said. “He’d walk out of a meeting saying, ‘We’re doomed, we’re doomed.’ But then he’d think of something clever.”

When he died he owned three Jeep Wagoneers and a Chevrolet Suburban. He figured out how to take rust off bumpers by running current through an electrochemical cell and reversing the process of oxidation.

Mueller lived with disassembled engines in her living room. Dillon detested the electronic dashboards on new cars and insisted that theirs have windows that had to be rolled up by hand.

“He was many things, but he was never boring,” she said. “Life is already pretty dull without him.”

In addition to Mueller, Dillon is survived by three daughters, Shannon, Sarah and Megan. A private memorial service is planned.