1D Diamond Crystal - might be a carbon fullerene molecule
A continuous pseudo-one dimensional diamond crystal- maybe a nanotube?

The Fountains of Paradise (1978)

Alien Watch on Earth
Monitoring of Earth to ascertain its level of development.

Loophole (1946)

Associators
Computer system finds correlations.

Against the Fall of Night (1948)

Asymptotic Drive
A propulsion drive that used a tiny black hole to generate energy.

Imperial Earth (1976)

Automatic Control Car
An autonomous vehicle.

Imperial Earth (1976)

Beeper
A handheld radar set, used to find items that have drifted off.

Islands in the Sky (1952)

Biot
A biological robot.

Rendezvous With Rama (1972)

Broomstick - move in space
Device to ease movement in a zero-gravity environment.

Islands in the Sky (1952)

Central City (Lunar Habitat)
An early example of a non-military lunar habitat.

Earthlight (1955)

Central Computer
A computer capable of running an entire city.

The City and the Stars (1948)

Computers Can Dream
A sufficiently complex AI computer can have activity similar to that of a human dreaming.

2010: Odyssey Two (1982)

Comsole (Home Communications Console)
A home computer, connected to data services.

Imperial Earth (1976)

Control Screen
An alien display device.

Childhood's End (1953)

CORA - Coronary Alarm
An implanted (or worn) ECG monitor that warns the user of coronary events.

The Fountains of Paradise (1978)

Cutoff Switch - a cable guillotine
A means of instantaneously switching off an artificial intelligence.

2010: Odyssey Two (1982)

Cylinder Space Suit
A mostly rigid, cylindrical space suit.

Islands in the Sky (1952)

Diaspar Memory - everyone gets a copy
The city's memory could store works of art, and reproduce them upon request.

The City and the Stars (1948)

Dragonfly Sky-Bike
An ultralight human-powered flyer.

Rendezvous With Rama (1972)

Dust-Cruiser
Specialized lunar transport able to negotiate dust-filled craters on the Moon.

A Fall of Moondust (1961)

Dust-Ski - ski-doo for lunar powder
Special vehicle adapted for quick travel over powdered lunar soil.

A Fall of Moondust (1961)