# How the First Wireless Television Remote Control Works

> Robert Adler's 1957 invention of the Space Command remote, which used ultrasonic sound waves to control television functions without wires or batteries.

- **Patent:** US 2817025
- **Original title:** Control system
- **Owner:** Zenith Radio Corp
- **Granted:** 1957
- **Status:** Public domain (expired)
- **Times cited:** 30
- **Field:** consumer_electronics, mechanical

## What it does

The patent describes a remote control system that uses ultrasonic sound pulses to trigger specific functions on a television set. The remote contains mechanical hammers that strike aluminum rods of different lengths when a button is pressed, creating high-frequency sound waves above the range of human hearing. A microphone on the television receiver captures these specific frequencies, which are then converted into electrical signals to perform actions like changing channels or adjusting volume.

## What it does NOT cover

- Does not cover infrared (IR) remote controls, which use light pulses rather than sound waves.
- Does not cover Bluetooth or Wi-Fi based remote controls.
- Does not cover systems that require a direct electrical wire connection between the remote and the TV.
- Does not cover digital signal processing or complex data transmission protocols.

## The clever bit

By using mechanical sound generation, the remote required no batteries, making it a truly self-contained, maintenance-free device that lasted for decades.

## Real-world examples

1. Zenith Space Command 400 remote control
2. Early ultrasonic TV tuning systems

## Why it matters

This invention effectively launched the modern era of television convenience, allowing viewers to control their sets from across the room. It solved the problem of the 'Space Command' predecessor, which used light and caused accidental channel changes from sunlight, by moving to sound frequencies that were less prone to environmental interference.

## Frequently asked questions

### What does How the First Wireless Television Remote Control Works cover?

Robert Adler's 1957 invention of the Space Command remote, which used ultrasonic sound waves to control television functions without wires or batteries.

### Who owns patent US 2817025?

Zenith Radio Corp owns this patent, granted in 1957.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 2817025 cited by?

This patent has been cited by 30 later patents that build on its ideas.

### What problem does this patent solve?

This invention effectively launched the modern era of television convenience, allowing viewers to control their sets from across the room. It solved the problem of the 'Space Command' predecessor, which used light and caused accidental channel changes from sunlight, by moving to sound frequencies that were less prone to environmental interference.

### What does this patent NOT cover?

Does not cover infrared (IR) remote controls, which use light pulses rather than sound waves.

**Full plain-English explainer:** https://patentbrief.org/patent/us/2817025/tv-remote-control-adler-zenith

**Original patent:** https://patents.google.com/patent/US2817025

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [Nikola Tesla's Remote Control System for Boats](https://patentbrief.org/patent/us/613809/tesla-remote-control-teleautomaton) — Nikola Tesla's 1898 patent for controlling a boat's movement and steering from a distance using radio waves and electrical signals.
- [How the First Home Video Game Console Worked](https://patentbrief.org/patent/us/3659285/video-game-console-magnavox) — Ralph Baer's 1969 patent for the Magnavox Odyssey, the first home video game system, which generated controllable dots on a standard television screen using analog circuitry.
- [How the Theremin Makes Music Without Touching Anything](https://patentbrief.org/patent/us/1661058/theremin-leon-theremin) — Leon Theremin's 1928 patent for an electronic musical instrument that generates sound based on the proximity of a performer's hands to metal antennas.
- [How the Classic Operation Board Game Works](https://patentbrief.org/patent/us/3333846/operation-game-electric-probe) — A 1967 patent for an electronic game where a player uses a conductive probe to navigate a path without touching the sides, triggering a signal if they fail.
- [How Marconi Patented Early Wireless Telegraphy Signals](https://patentbrief.org/patent/us/586193/radio-wireless-marconi) — Guglielmo Marconi's 1897 patent for sending electrical signals through the air to enable early wireless communication.