How Ultrasonic Remotes Work

One of the first remote controls ever made used ultrasonic technology.

The remote control sitting on your coffee table may seem like a fairly simple electronic device, but it has undergone several changes during its development. Some of the earliest remote controls operated using ultrasonic technology.

Function

Ultrasonic remotes use very high frequency sounds (beyond the threshold of human hearing) to control devices. They use small aluminum bars that were cut to different lengths to produce different sounds. One bar turns the channel up, the second turns the channel down, the third turns the sound on an off and the last turns the power on and off. The bars are struck by a trigger mechanism that operates a hammer inside of the remote.

History

The ultrasonic remote control was invented in 1956 by an Austrian engineer named Robert Adler, who worked for the Zenith Electronics Corporation. When it finally went into production, it was called "Zenith Space Command" and it greatly increased the sales of televisions, which had themselves only recently been invented. Ultrasonic remotes are rarely seen in electronics in 2010, but still have some applications, such as in dog training.

Fun Fact

Because the aluminum bars transmitted the sound mechanically without the use of electricity, the early ultrasonic remotes worked without batteries.

References

• The Great Idea Finder: Remote Control History
• 4QD-TEC: Ultrasonics--Remote Control and Intruder Detector
• IEEE-UFFC: In Memoria--Robert Adler