The Basics of Remote Control

Remote Control is the ability to operate a machine or device, such as a television set, from a distance. The most basic remotes are operated by pushing buttons, but there are also high-tech models that use LCD touchscreens and joysticks to input commands.

Infrared (IR) remote controls send signals through invisible beams of light, typically a 940 nanometer wavelength LED. Multichannel remotes have more sophisticated technology that modulates carrier signals and uses frequency filters to separate different functions.

Nikola Tesla

Invented by Nikola Tesla, the remote control (or radio control, abbreviated as RC) is an electronic device that allows you to operate an object or machine from a distance. It uses electromagnetic waves to transmit control signals, which are received by the object’s receiver. RC is used for everything from garage door openers and automobile keyless entry systems to remote-controlled model vehicles and industrial equipment. It is also increasingly being used by the military and scientific research organizations to control unmanned aerial vehicles.

Serbian-American engineer and inventor Nikola Tesla made dozens of important breakthroughs in electric power production, transmission and application. He designed the alternating current electrical system, which is still in use today, and invented the Tesla coil. He worked briefly for Thomas Edison before selling his patent rights to George Westinghouse in 1884.

In 1898, Tesla demonstrated one of the earliest versions of a remote control by sending signals to a small boat at Madison Square Garden. Three years later, Leonardo Torres Quevedo presented a robot called Telekino at the Paris Academy of Science that was controlled by commands transmitted through electromagnetic waves, which are similar to those used in modern remote controls.

After a series of greater experiments, Tesla was unable to find sufficient funding to continue his work and was forced to sell his patents to Guglielmo Marconi. He died in poverty in January 1943, at the age of 86.

Leonardo Torres

The earliest example of remote control was developed by the Spanish engineer Leonardo Torres y Quevedo. He created a system, known as Telekino, that used radio signals to control mechanical movements at a distance. His device allowed him to send up to 19 different commands.

He started developing the Telekino around 1901 as a way to test dirigibles without risking human lives. In 1906, he tested the device in the port of Bilbao by steering a ship from a distance of two kilometers. He also demonstrated it at the Paris Academy of Sciences and obtained patents in Spain, France, and England.

Using the principle of binary numbers, he determined that telegraphic signals could be sent as codes to control the movement of mechanical devices. He discovered that if he changed the state of an asynchronous data transmission, he was able to change the position of a needle or control the action of any other mechanism.

Torres y Quevedo also invented the first automatic electromechanical calculating machine in 1920, which was in some ways a precursor to modern computers. He worked to solve complex algebraic equations and achieve Charles Babbage’s dream of a mechanical machine that could think. He also helped develop a formal international language for technical documentation and mechanical drawings. This he published in 1907 in the paper “Sobre un sistema de notaciones y simbolos destinados a facilitar la descripción de las maquinas.” This was an early version of the programming languages we use today.

Zenith Space Command

Zenith was the first company to develop a remote control for a television set. It was called Space Command and worked by sending inaudible sound waves to adjust the TV’s tuning. It was battery free and there were no wires to worry about. It was very expensive, however, because it required a receiver in the TV set that used six additional vacuum tubes to pick up the signal. This increased the cost of a compatible Zenith TV set by 30 percent.

A physicist named Robert Adler designed the device. He was skeptical of using batteries because people would think the remote control was broken when it stopped working. He proposed using ultrasonics, which are inaudible to the human ear, instead. His invention worked by using physical buttons that triggered spring-loaded hammers to hit metal rods tuned to the appropriate frequencies. This generated a click that was picked up by the receiver in the TV and acted as a signal to change the channel.

Although it was not the first remote control, Space Command was an important step in removing the need for viewers to get out of their chairs. It also helped to mute commercials, which were still a common feature of most TV programs in 1956. Despite the clunky, mechanical design, Space Command was a major success and lived on for a quarter of a century until it was replaced by infrared.

CL 9

CL 9 was a remote control company founded by Apple Computer co-founder Steve Wozniak in 1985 and remained in business until 1988. Its flagship product was the 6502-based CL 9 CORE generic universal remote control, which Wozniak called “the first programmable universal remote.” The remote is able to learn, or record, IR signal patterns from other remotes and uses 16 key plus function buttons for a total of 256 keyable codes. A serial interface on the underside allows for a connection to a computer. After the CL 9 business closed, a company named Celadon bought their assets and continued to produce and support the Core CL 9.

Most remote controls for electronic devices emit a beam of near infrared light (about 940 nm wavelength) that is picked up by sensors on the device being operated. The infrared diode modulates at a rate corresponding to the particular function being triggered; video cameras can detect this by seeing a series of pulses that appear as purple light. Some remotes include dip-switches to choose the type of code used, ranging from fixed to rolling codes. Rolling code is a more secure technology that does not repeat the same codes as quickly, and it is now widely adopted by garage and gate remotes.