A simple and inexpensive light source for research in visual neuroscience

Demontis, Gian Carlo; Sbrana, Andrea; Gargini, Claudia; Cervetto, Luigi

doi:10.1016/j.jneumeth.2005.01.007

Cited by 9 publications

(10 citation statements)

References 11 publications

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“…LEDs are more common, low cost, easily portable, have low power consumption and provide flexible means to customise a visual stimulus [52][53][54]. LED stimulus has the advantage of generating the required colour using RGB LEDs in the same source thus avoiding the issues in attention shifts [50].…”

Section: Related Workmentioning

confidence: 99%

A Configurable, Inexpensive, Portable, Multi-channel, Multi-frequency, Multi-chromatic RGB LED System for SSVEP Stimulation

Mouli

Palaniappan

Sillitoe

2014

Brain-Computer Interfaces

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Steady state visual evoked potential (SSVEP) is extensively used in the research of brain-computer interface (BCI) and require a controllable and configurable light source. SSVEP requires appropriate control of visual stimulus parameters, such as flicker frequency, light intensity, multi-frequency light source and multi-spectral compositions. Light emitting diodes (LEDs) are extensively used as a light source as they are energy efficient, low power, multi-chromatic, have higher contrast, and support wider frequency ranges. Here, we present the design of a compact versatile visual stimulus which is capable of producing simultaneous multiple frequency RGB LED flicker suitable for a wide range of SSVEP paradigms. The hardware is based upon the open source Arduino platform and supports on-the-fly reprogramming with easily configurable user interface via USB. The design provides fourteen independent high output channels with customisable output voltages. The flicker frequencies can be easily customised within the frequency range of 5-50 Hz, using a look-up table. The LED flickers are generated with single RGB LEDs which generate the required colour or frequency combinations for combined multi-frequency flicker with variable duty cycle to generate SSVEP. Electroencephalogram (EEG) signals have been successfully recorded from five subjects using the stimulator for different frequencies, colours, duty cycle, intensity and multiple frequency RGB source, thereby demonstrating the high usability, adaptability and flexibility of the stimulator. Finally we discuss the possible improvements to the stimulator which could provide real time user feedback to reduce visual fatigue and so increase the level of user comfort.

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Section: Related Workmentioning

confidence: 99%

A Configurable, Inexpensive, Portable, Multi-channel, Multi-frequency, Multi-chromatic RGB LED System for SSVEP Stimulation

Mouli

Palaniappan

Sillitoe

2014

Brain-Computer Interfaces

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“…Light-emitting diodes (LEDs) have become more and more common as a low-cost and flexible way to provide light stimuli in vision research (Nygaard and Frumkes, 1982;Scholfield and Murdock, 1987;Watanabe et al, 1992;Pokorny et al, 2004;Fadda and Falsini, 1997;Demontis et al, 2005;da Silva Pinto et al, 2011;Rogers et al, 2012). LEDs offer easier and more versatile control of light characteristics (Schubert and Kim, 2005) compared to traditional light sources such as xenon, mercury, metal halide and halogen lamps which often require various auxiliary devices in experimental settings such as a set of filters for spectral tuning and shutters to control exposure duration.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the widespread use of LEDs in scientific research, there is only a handful of papers dedicated for the design of LED stimulators for research purposes (Watanabe et al, 1992;Pokorny et al, 2004;Fadda and Falsini, 1997;Demontis et al, 2005;Nishimura et al, 2006;Albeanu et al, 2008;da Silva Pinto et al, 2011;Rogers et al, 2012). Additionally, the existing approaches have relied on either off-the-shelf proprietary laboratory equipment (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Fadda and Falsini, 1997), or advanced electronics from the end-users (e.g. Watanabe et al, 1992;Demontis et al, 2005). da Silva Pinto et al (2011) recently described an opensource portable LED stimulator promoting the reproducibility of their device by providing the hardware schematics, layouts, parts lists and application source freely on their support website (http://sites.google.com/site/mculedstimulator/), the cost of their hardware parts being around $100 (∼76D).…”

Section: Introductionmentioning

confidence: 99%

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An inexpensive Arduino-based LED stimulator system for vision research

Teikari

Najjar

Malkki

et al. 2012

Journal of Neuroscience Methods

106

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“…Many solutions have in fact been developed to circumvent such problems while making LEDs display time-varying stimuli such as brief flashes, flickers and more complex temporal waveforms (e.g. Nygaard and Frumkes, 1982;Swanson et al, 1987;Watanabe et al, 1992;Falsini, 1996, 1997;Demontis et al, 2005;Hogg, 2006). Although such solutions rely on relatively simple electronics, they are often coupled with off-the-shelf proprietary laboratory equipments like waveform generators, which brings a number of disadvantages: it raises the price of the stimulation device, especially if several channels need to be driven simultaneously; it diminishes the flexibility and user-friendliness generally associated with software-based solutions; it depends on electrical line power, thereby offering little portability to the system; and finally, it relies on equipments which, for being effectively black-boxes, limit the scalability of the project development.…”

Section: Introductionmentioning

confidence: 99%