Brain-wave analyzer

Doc wearing the device.

Doc: "You want me to buy a subscription to the Saturday Evening Post?"

Marty: "No."

Doc: "You want me to make a donation to the Coast Guard Youth Auxiliary?"

Marty: "Doc, I'm from the future. I came here in a time machine that you invented and I have to get back to the year 1985."

— First discussion between Marty and 1955 Doc

The brain-wave analyzer was one of the inventions Emmett Brown created. It was intended to allow him to read someone else's thoughts. When Marty McFly arrived at his house for the first time, Doc disconnected the machine from his dog Copernicus, and tested the machine on him as he arrived on his doorstep. It consisted of a helmet with a metal geodesic framework that held several cylindrical devices pointed at his head, with electrical wires that led from each of these devices to either a small helmet strapped to his dog's head, or to a suction cup that he stuck to Marty's forehead.

His first guess was that Marty "had come from a great distance", which was not literally true, since Marty never left Hill Valley, but he did travel a great distance in time. His second guess, selling subscriptions to the Saturday Evening Post door to door, was a common occupation, but also not correct. After noticing that Marty appeared to wearing a life preserver, Emmett made a wild guess that he was collecting donations for the Coast Guard Youth Auxiliary. He did not know that only a short time beforehand, when Lorraine's mother guessed that he was a sailor, Marty answered that he was a member of the Coast Guard. If this was not an amazing coincidence, then this device may have been Emmett's first invention that actually worked.

"Do you know what this means? It means that this damn thing doesn't work at all!"

—Doc

A week later, while Doc is reading the letter from his 1885 counterpart, Marty tries on the brain-wave analyzer helmet as he looks at the inventions in the lab.

At some later date, Doc Brown and his team at the Institute of Future Technology successfully a much smaller version of the brain-wave analyzer that is used to read one's own thoughts and display them on a LED screen. The device works by harnesing electro-magnetic impulses created by synaps-disponses from both the cerbral-malbestare. Mind waves are transmitted at a mind obitting rate into the ciruitry, thus tranlating thoughts into written form, in other words reading your mind.

Appearances

• Back to the Future
• Back to the Future Part III
• Back to the Future: The Ride

Sources

• Back to the Future novelization (regarding name of invention)