Artificial sensors and probes enable us to overcome the limitations of our human senses and extend them in novel and useful ways, using the scientific concepts of electricity and waves.
Find out more about the development of electrical sensors in this timeline.
600BC – Discovering static electricity
Thales of Miletus in Greece makes a series of observations on static electricity created by rubbing different kinds of objects together. He manages to get sparks from rubbing an amber rod with fur.
132AD – Earthquake sensor
Zhang Heng of China builds a large bronze vessel designed to measure the direction of an earthquake. The inner mechanics of this seismoscope remain a mystery.
1600 – Deriving the word ‘electricity’
William Gilbert (England) conducts a study on static electricity produced by rubbing amber. He develops the word ‘electricus’ from the Greek word ‘elektron’ meaning amber. The words ‘electricity’ and ‘electric’ are derived from this word.
1660 – First electrostatic generator
Otto von Guericke (Germany) invents the first electrostatic generator and makes the study of electricity possible, leading to an understanding of types of electricity (positive and negative) and materials that are conductors or insulators.
1800 – Early electric battery
Alessandro Volta (Italy) invents a reliable source of electrical energy. The battery is made from alternating layers of zinc and copper with layers of paper soaked in brine between the metal plates.
1820 – The electricity-magnetism link
Hans Christian Oersted (Denmark) discovers the link between electricity and magnetism during a lecture demonstration. He had been looking for a link between electricity and magnetism for some time.
1827 – The law of electricity
Georg Ohm (Germany) defines relationship between voltage, current and resistance in circuits. Current passing through a conductor is directly proportional to voltage but indirectly proportional to resistance. As resistance increases, current decreases for a given voltage.
1831 – Electromagnetic induction
Michael Faraday (England) discovers the principles of electromagnetic induction. He later uses the ideas to construct an electric dynamo that is the precursor of present day power generators.
1873 – Electromagnetic field equations
James Clerk Maxwell (Scotland/England) discovers the equations for electromagnetic field – the existence of electromagnetic waves travelling through space at the speed of light.
1897 – Discovery of the electron
Joseph John Thomson (England) identifies that the cathode ray is a stream of negatively charged particles, which are later called electrons.
1904 – Diode rectifier
John Ambrose Fleming (England) invents the first thermionic valve (a vacuum-tube or diode rectifier) that converts alternating radio signal currents to direct currents.
1929 – Remote sensors developed
Robert Bureau (France) invents the radiosonde – a remote sensor attached to a balloon that measures atmospheric data such as temperature, pressure, wind speed, altitude and relative humidity. Today, there are over 800 radiosonde launching sites worldwide.
1930 – Sensing temperature
Samuel Ruben (USA) invents the temperature sensor – the thermistor – a type of resistor with resistance varying according to its temperature.
1947 – Invention of the transistor
John Bardeen and Walter Brattain (USA) refine William Shockley’s amplifier device to invent the transistor. Its ability to switch on and amplify electronic signals becomes the building block of modern electronic devices. The three are awarded the 1956 Nobel Prize in Physics.
1948–1949 – First autonomous robots
William Grey Walter (England) creates Elmer and Elsie, the first electronic autonomous robots, which can sense light and external objects and use their remote sensors to navigate an area.
1957 – Sputnik launch
The world’s first artificial satellite Sputnik 1 is launched into an orbit round the Earth starting the space age and the US-USSR space race, with huge spin-offs in the area of science and technology.
1959 – First microchips built
The integrated circuit is developed by Jack Kilby and Robert Noyce (USA) working independently, revolutionising the world of electronics. A miniaturised electronic circuit is manufactured on a thin semiconductor material. Kilby uses germanium and Noyce uses silicon.
1960 – GPS in operation
The first satellite navigation system is successfully tested. Up to 32 navigation satellites now orbit the Earth enabling GPS receivers to accurately triangulate their position.
1961 – Industrial robots developed
Unimate, the first industrial robot, starts work in the General Motors assembly line in New Jersey, America. Its creators, George Devol and Joseph Engelberger, start Unimation, the world's first robot manufacturing company.
1960–1970 – Electronic seismographs
These seismographs use an electronic feedback mechanism to hold a mass steady during an earthquake. The force required to achieve this is digitally recorded.
1985 – GPS to track migrations
The migration of marine loggerhead turtles is tracked using GPS. A saltwater switch is used to save power while the turtles are underwater and unable to send signals.
2001 – GeoNet launched
EQC and GNS Science collaborate on a network of geophysical instruments, automated software applications and skilled staff, which detects, analyses and responds to earthquakes, volcanic activity, large landslides, tsunami and the slow deformation that precedes large earthquakes.
2008 – MiMOMax Network Digital Link (NDL)
This software flexible, digital radio link designed for linking multiple data sources to a base station uses narrow band radio channels and MiMO (multiple input/multiple output) technologies to send data at a very fast rate.