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SMART-guarding water resources with first-of-its-kind holistic sensor

SMART-guarding water resources with first-of-its-kind holistic sensor

Innovative and holistic low-cost LEDIF provides in-situ, real-time optical sensing of water chemistry

Boosts protection of water resources by providing multi-species contaminants and natural substances detection utilizing a proprietary tri-optical design

Improves efficiency and accuracy of chemical assessment of reservoir and marine waters

LEDIF (left, 1st pix) is placed inside the Autonomous Underwater Vehicle (AUV) dubbed the NUS ARL STARFISH and launched at a reservoir.

  1. Singapore, 17 Feb 2014 – Researchers at the Singapore-MIT Alliance for Research and Technology (SMART) [新加坡-麻省理工学院科研中心] have developed a low-cost and compact multi-platform compatible sensors that provides a holistic solution for the monitoring of water resources. Like a “lab-on-a-chip”, this sensor dubbed ‘LEDIF’, is a powerful “lab-on-AUV” (see picture above) that would go a long way in reinforcing efforts in safeguarding water resources while potentially improving the efficiency and accuracy of monitoring water quality.

  2. LEDIF (LED-Induced Fluorescence) [二极管引发荧光] is a field-deployable tri-optical instrument that uses a combined optical technology to identify and quantify contaminants and natural substances in water. This combined optical technology includes:

    • Fluorescence – Emission of light by a substance that has absorbed light or other electromagnetic radiation

    • Absorbance- Quantitative measure expressed as a logarithmic ratio between the radiation falling upon a material and the radiation transmitted through a material

    • Scattering - Irregular dispersal of waves or particles

LEDIF pioneers the theme of “bringing lab to water” with an automated standalone tri-optical holistic technology featuring both multi-excitation and broadband sources to enable “lab-like” water chemistry assessment to be performed in-situ to monitor water resources in real-time.

Holistic solution

1. LEDIF (see Factsheet) is capable of detecting, measuring and 3-D mapping contaminants (e.g., oil spill, carcinogen hydrocarbons) when put on-board autonomous platforms. Beyond contaminants, it is capable of detecting natural substances (e.g. algae, coloured dissolved organic matter) in marine and urban environments; and climate-related sensing. Commercially available in-situ sensing probes are usually limited to physical water properties or target a specific chemical.

2. Beyond being inside a ‘Yellow Submarine’ [as shown in picture of the STARFISH autonomous underwater vehicle which is developed by the Acoustic Research Laboratory of the Tropical Marine Science Institute at the National University of Singapore (NUS)], the LEDIF is actually compatible with multi-platforms (e.g. Autonomous Surface Vehicles, fixed platform, and portable mode of sensing) to provide both 3-D chemical mapping and long-term continuous monitoring. These applications are important in helping to ensure that waters resources are clean from industrial pollution, oil spills and harmful algae growth.

3. Currently, most high precision organic matter detection procedures involve laboratory analysis of water samples, which would probably be time-consuming and costly. Grab water samples at specific spots may also fail to adequately capture the spatio-temporal variability, which may hold the key to understanding the biogeochemical processes in water bodies. In recent years, in-situ water quality instruments installed on water bodies have helped to provide continuous, real-time data, but are typically limited in spatial coverage due to their fixed locations.

4. Dr Kelvin Ng Chee-Loon (黃智倫), Research Scientist at SMART Centre for Environmental Sensing and Modeling (CENSAM), said: “LEDIF, our proprietary technology has myriad applications from detecting accidental and intentional pollution for implementing immediate counteractive action to quantifying natural occurring substances for research studies; providing a holistic solution capable of 24/7 surveillance of water resources. Beyond detection, its ability to provide a 3-D chemical mapping of the entire water body (which can be as large as 2 soccer fields), empowers agencies to better monitor the water situation on a large scale in the long term.”

5. Professor Harold Hemond, SMART Principal Investigator and the William E. Leonhard Professor of Engineering at MIT, said: “Having worked on this technology for the past 5 years, we are confident that our research will translate into a very powerful tool for industries and governments alike in safeguarding and protecting our environment and water resources.”

6. This research is based on the paper “A multi-platform optical sensor for in situ sensing of water chemistry”. The abstract can be found at The AUV deployment conducted locally was done in collaboration with the Acoustic Research Laboratory of the Tropical Marine Science Institute at NUS (more on NUS ARL STARFISH can be found at The research is funded by the Singapore National Research Foundation (NRF), Prime Minister’s Office, Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) programme.

About SMART The SMART Centre is a major research enterprise established by the Massachusetts Institute of Technology (MIT) in partnership with the National Research Foundation of Singapore (NRF) since 2007. It is the first entity in the Campus for Research Excellence and Technological Enterprise (CREATE) developed by NRF.

The SMART Centre serves as an intellectual hub for research interactions between MIT and Singapore. Cutting-edge research projects in areas of interest to both Singapore and MIT are undertaken at the SMART Centre. SMART comprises an Innovation Centre and five Interdisciplinary Research Groups (IRGs): BioSystems and Micromechanics (BioSyM), Center for Environmental Sensing and Modeling (CENSAM), Infectious Diseases (ID), Future Urban Mobility (FM) and Low Energy Electronic Systems (LEES).

About SMART CENSAM IRG Using measurements from a variety of sensors and sensor networks, the Center for Environmental Sensing and Modeling (CENSAM) IRG aims to develop an accurate and predictive model of the natural and built environment of Singapore that seamlessly transitions between different scales, from the level of a single building or facility to the level of the state, including the surrounding seas.

About CREATE CREATE is an international collaboratory housing research centres set up by top universities. At CREATE, researchers from diverse disciplines and backgrounds work closely together to perform cutting-edge research in strategic areas of interest, for translation into practical applications leading to positive economic and societal outcomes for Singapore.

The interdisciplinary research centres at CREATE focus on four areas of interdisciplinary thematic areas of research, namely human systems, energy systems, environmental systems and urban systems. More information on the CREATE programme and the CREATE factsheet can be obtained from

SMART Contact person : Pauline Teo, Corporate Communications Specialist Email :


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