TRUMAN — When Tom Rahm gets on a 4-foot ladder to make a repair in his pig barn, the residents get curious. The swine nose around, give him a few bumps and maybe knock him off if he’s not careful.

From the problem of nosy pigs, the LadderGuard was born. It’s a rectangular piece of tubing that fits snugly near the bottom of a ladder. A wire wrapped around the tube delivers 1 joule of electricity to the pig that noses into it.

It’s enough, Rahm says, to make the pig back off but not hurt it.

“They won’t squeal, because PETA doesn’t want pigs to squeal,” he says jokingly.

Rahm, dressed in jeans, a T-shirt and a baseball cap, looks the part of a farmer. He’s invented dozens of the gadgets like this one.

“All these ideas come about because of somebody’s problem,” said the 61-year-old from rural Truman.

In the case of the LadderGuard, safety is a prime concern of farmers, and insurance companies may be another customer.

Rahm isn’t a big self-promoter. He only agreed to talk to a reporter at the urging of Jill Klinger, new enterprise and emerging business director at Greater Mankato Growth. Klinger has been helping connect Rahm with opportunities in the business world.

Has he made much money from his inventions? Nope. He’s only patented two over the decades. But each little invention, each of the “well over 50” things he’s built has been at least a small improvement in getting things done.

Rahm won the first- and second-place prizes at the 2009 Minnesota Inventors Congress.

The winning invention was a solar-powered rail crossing sign to warn motorists of an oncoming train.

Those electronic systems are common at busy crossings, but they cost roughly $200,000 each and are typically funded by the federal government.

Rahm’s version would be much cheaper and might be attractive to townships.

He’s getting some help on this invention and others from John Frey, former dean of Minnesota State University’s College of Science, Engineering and Technology.

Frey works with other inventors, but said “Tom happens to be one who’s more consistent.

His mind is loaded with ideas. That’s the part that intrigues me about him.”

Rahm now rents his land out instead of farming it himself.

“You meet more people doing this junk,” he says, referring to inventing.

The first part of inventing for Rahm is listening to someone else’s problem.

“You never learn anything with your mouth open.”

Take the time he was in a Fairmont machine shop this spring and listened to the complaints of two guys who spend three hours every day drilling holes in a golf course. Eighteen times a day the guys bend over, drive an old-fashioned device into the ground and core a new hole.

It’s a delicate operation because dirt and sand can’t fall in the hole, which might create a small depression. Golfers might like to see their ball rolling toward the hole, but it would take some of the skill out of putting.

So Rahm modified the device so that a power drill can do the work that muscle performs now. The drill locks into one of two bits and drives the metal shaft into the ground.

He calls it the Green Cutter.

“That’s harder than anything else, trying to come up with a name for it,” he said.

Rahm’s next big project is an odor-free hog barn. It would do away with the smelly pit typically used to store hog manure. The barn of the future would also be more environmentally friendly, and perhaps use the waste to generate ethanol.

“They’d be happier pigs,” he says.

His advice to aspiring inventors is to be persistent.

“You can quit as many times as you want but don’t give up. Because all of a sudden, the light will come on again.”