The protagonist is a young teenage boy, Caucasian, I think. He only has one parent, although I'm not certain if it's his father or his mother. I believe the other parents died in a fire, where the child just barely made it out alive himself. I think he has a younger brother. They move into a new town and find that the house is cluttered with old junk and appliances. I want to say there's a strange phone call (garbled voice talking, not responding to anything the boy says) and something falls and hits his head when he opens up an overhead door into the attic. Not long after moving in, they decide to do a yard sale to get rid of the junk and, in kind of a befuddled state due to the head trauma, the kid manages to sell almost everything, often at bargain prices. Not long afterwards, he learns that much of it are devices with strange properties, and the rest of the trilogy is him and his friends trying to round up the devices. He had competition in the form of an organization that turns out to be run by an extremely old (and possibly slightly undead) Thomas Edison. There is also at least one world-ending threat that he has to deal with (I'll mention what I remember of that later). Some of the inventions I remember:
- A baseball glove that attracts balls and a baseball bat that can always hit the oncoming ball (the bat is lost when he uses it to deflect an oncoming asteroid that would have devastated the Earth, hinted to have been attracted by the glove).
- A tape recorder that plays back the truth when someone is recorded speaking.
- A battery that can bring a dead person back to life (one of his friends gets killed, maybe by the same device, with an electrical discharge, and a source of drama/humor is that said friend drops dead every time the battery gets disconnected, but his parents somehow stay unaware). Edison is particularly after this one to restore his life.
- A fan that generates hurricane-force winds (I remember this was one of the items he retrieved from a woman at the yard sale, whose house had been devastated as a result of it)
- A telephone that lets him talk to Nikola Tesla in the past, although the connection was bad
The eventual climax of the tale is
He retrieves all of the devices and attaches them to the house in a way that turns it into one huge machine that does... something... but also hurls him back in time. He saves his one parent from the fire (his mother, maybe?) and somehow becomes both the voice from the strange phone call, and possibly Nikola Tesla himself, making it a stable time loop.
I read this somewhere after 2010, I think with books checked out from the Pittsburgh library. Unfortunately, that's a lot of history to try to plumb through.