Edinburgh Sensors Ltd

Edinburgh Sensors are proud to be global providers of high quality Gas Sensor solutions. Our diverse range of gas sensors use the latest technology to enable reliable, accurate and continuous gas detection. Established for over 20 years, Edinburgh Sensors use proven technology to deliver OEM Gas Sensors and Gas Monitors / Indoor Air Quality Monitors that are smart, efficient and easy-to-use. Our customers know that using our Sensors not only saves them time, they save them money in an eco-friendly way. The application of our continued research and development has contributed to several major advances in the world of infrared gas sensing and delivered a comprehensive portfolio of products for the detection of CO, CO2, CH4 and various refrigerants. Such technology has been widely accepted and standardised by many other gas sensor manufacturers worldwide.

Company details

4 Bain Square, Kirkton Campus , Livingston , EH54 7DQ United Kingdom

Locations Served

Our Distributors

Business Type:
Industry Type:
Monitoring and Testing - Air Monitoring and Testing
Market Focus:
Globally (various continents)
Year Founded:
1,000,000 - 10,000,000 €

Edinburgh Sensors, a division of Edinburgh Instruments, is a world-class customer-focused provider of quality gas sensing solutions.

Since 1980, we have designed and manufactured a comprehensive range of gas sensors and Indoor Air Quality Monitoring solutions based on non-dispersive infrared (NDIR), fail safe gas sensing technology.

The application of our continued research and development has contributed to several major advances in the world of infrared gas Sensing and delivered a comprehensive portfolio of products for the detection of CO, CO2, CH4 and various refrigerants. Such technology has been widely accepted and standardised by many other gas sensor manufacturers worldwide.

Our diverse range of robust OEM gas sensors and Gas Monitors provide consistent, precise, and continuous detection. With a global reputation for high performance, our products are an ideal solution for those applications where accuracy, safety and reliability are paramount.

We continue to pioneer developments as we explore new opportunities using NDIR and non-NDIR technologies. Backed by our widely recognised technological achievements we are firmly committed to our customers and invest in our people.

We stand by our global reputation for excellence.

Our existing products support a wide range of market segments and applications including biogas, brewing, process control, gas delivery, industrial manufacturing, personal safety, process control, and horticulture and landfill gas measurement by detecting and measuring the following gases: Carbon dioxide, methane, carbon monoxide and refrigerants.

Our range of gas sensors are available in either OEM format for integration into a customer system or as a complete monitor providing simple continuous monitoring and control of gas concentration levels.

Our service support and our technical know how is what gives our sensors the enviable reputation for being fast, accurate, reliable and robust.

Benefits of Edinburgh Sensors Instruments:
  • Simple, easy and effective
  • Non-imaging optical systems
  • Speed of response
  • Digital Precision
  • Flexibility
  • No moving parts
  • No consumable chemicals
  • Long lifetime
  • Robust Build

Our existing product range is based on a no moving parts, non-dispersive infrared (NDIR) gas detection and we are presently working to explore new and exciting technologies.

Benefits of dual wavelength NDIR gas sensor
  • Non dispersive infrared technology is fail-safe; the most common failure mechanisms will give a high concentration indication, allowing for investigation.
  • The technology is able to detect chemically inactive gases, whose aversion to reaction makes them difficult to detect using chemical methods.
  • In the majority of cases IR absorption is highly specific so that a particular gas may be reliably detected in complex compositions of gas.
  • There are many situations where IR will work while other methods will fail e.g. the detection of Alcanes in oxygen depleted atmospheres.
  • The IR Sensor is not consumed and so has a longer life than most chemical detection methods.
  • It is difficult to “poison” an IR sensor.

Edinburgh Sensors dual-wavelength products employ a number of key features:-

  • A tubular light guide optical system to transfer the IR radiation from the source to detector and also to act as a gas cell, this arrangement provides a greater than 90% overlap between the two beams thereby maximising sensor stability.
  • Electronic source modulation eliminating the need for moving parts.
  • A microprocessor to control the source and digitise the signal from the detector so that almost all signal processing is in the digital domain, very fast and free from analogue artefacts.  
  • A pressure sensor to allow the true gas concentration to be displayed without the need for an atmospheric pressure correction calculations.
  • Our sensors are easy to adapt enabling users to change filters and light sources.

The origins of infrared gas sensing go back a long way.  In 1800, the astronomer Sir William Herschel demonstrated the existence of a considerable amount of energy in the solar spectrum beyond the red end of the visible spectrum, what we now term infrared radiation.  It was his son John, in 1840 who discovered the existence of absorption bands in the infrared solar spectrum.  His apparatus could arguably be described as the first open path infrared gas detector, in this case using the sun as a source, the earth’s atmosphere as the gas path, a thermometer as a detector and with wavelength selection provided by a prism.  The absorption bands were caused by and indicated the presence of gases in the atmosphere, in particular water vapour.

The rest of the 19th century saw major advances in physics so that by the start of the 20th Century the principles behind the infrared absorption spectra of gases were known.  The molecular and atomic nature of matter inferred from Avogadro’s hypothesis and the work of the chemist John Dalton in the early 19th century followed by that of Ernest Rutherford and Neils Bohr in the early 20th century on the structure of the atom provided a usable model of the structure of matter. James Clerk Maxwell’s work in the mid 19th century on electromagnetism, culminating in his equations anticipating electromagnetic waves predicted the electromagnetic nature of infrared radiation.  The quantised nature of energy proposed by Max Planck in 1900 then prepared the way for Albert Einstein to round things off with his explanation of absorption and emission in 1911.

On the experimental front, the late 19th and early 20th century saw the observation of the absorption spectra of various gases, even the resolving of the rotational fine structure associated with certain simple molecules.  Measurements were, however, very difficult to make due to the lack of suitable devices and were principally aimed at extending the boundaries of knowledge rather than producing practical gas sensors.  Some work was done on photo-acoustic gas sensors for the detection of firedamp (methane) as early as 1881¬ (Bell A.G.  1881  Phil. Mag. 11, 510) but it was not until the development of non-dispersive infrared (NDIR) techniques that practical IR gas sensors were possible.  The first NDIR gas sensor was developed by Luft in 1943 (Luft K.V. 1943 Z. Tech Phys.  24, 97) and used closed cells containing the gas to be detected (target gas) as a method of wavelength selection.  In the 1940’s and 1950’s useful IR detectors became available.  A major advance occurred in 1955 with the development of the multilayer thin film interference filter for wavelength selection in the infrared, the first paper describing these devices being published by the founder of Edinburgh Sensors, then a post graduate research student (Heavens O.S. and Smith S.D. 1955 Proc. Manchester Conf. On Astronomical Optics).  Since that time, a wide range of practical NDIR gas sensors have been produced for use in industrial applications.

- See more at: http://www.edinburghsensors.com/Technology/history-of-ir-gas-sensing/#sthash.WZ2QemcO.dpuf

Our sensors products are used in a wide variety of gas sensing applications. Examples of these applications also include:

The infrared spectrum between 2 and 20µm is of use in gas detection because it is here that many gases show characteristic vibration/rotation absorption spectra with narrow, non-overlapping bands.  It is often possible to identify an absorption band which is virtually unique to a gas or group of gases (4.26µm for CO2, 3.3µm for hydrocarbons), so it is possible to make an IR gas sensor which is selectively sensitive to a specific gas or group of gases.

Even where a group of gases exhibit a common absorption band, as in the case of 3.3µm for hydrocarbons, it is often possible to identify and use some of the detailed features of the absorption band to make the sensor preferentially sensitive to one gas within the group.  
Most infrared sensors measure absorption by the gas and therefore have signals present at all gas concentrations.  As a result, it is easy to detect a fault in the system so that infrared gas sensors are generally regarded as ‘fail safe’.

The key features of infrared gas sensing as a technology are therefore its selectivity and its fail safe nature.