A low-cost, portable, micro-controlled device for multi-channel LED visual stimulation

Pinto, Marcos Antônio da Silva; Souza, John Kennedy Schettino de; Baron, Jerome; Tierra-Criollo, Carlos Júlio

doi:10.1016/j.jneumeth.2011.02.004

Cited by 16 publications

(16 citation statements)

References 25 publications

(26 reference statements)

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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%

“…However, existing visual stimulators [52,57,58] based on LEDs have their limitations, as they are limited in their customisation capabilities, are not easy to program and often not possible to control LEDs individually. For a BCI researcher with a non-technical background, designing an easily controllable visual stimulator is technically challenging, since it requires an understanding of electronics and programming.…”

Section: Related Workmentioning

confidence: 99%

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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%

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%

“…More detailed discussion on the advantages of LEDs over traditional light sources can be found in regard to the noise and stability characteristics (Brophy, 1967;Rumyantsev et al, 2004;Salzberg et al, 2005), and to biological applications such as in widefield microscopy (Holman, 2007) and visual neuroscience (da Silva Pinto et al, 2011).…”

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%

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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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An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection

Souza

Pinto

Vieira

et al. 2013

Computer Methods and Programs in Biomedicine

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The dynamic, accurate measurement of pupil size is extremely valuable for studying a large number of neuronal functions and dysfunctions. Despite tremendous and well-documented progress in image processing techniques for estimating pupil parameters, comparatively little work has been reported on practical hardware issues involved in designing image acquisition systems for pupil analysis. Here, we describe and validate the basic features of such a system which is based on a relatively compact, off-the-shelf, low-cost FireWire digital camera. We successfully implemented two configurable modes of video record: a continuous mode and an event-triggered mode. The interoperability of the whole system is guaranteed by a set of modular software components hosted on a personal computer and written in Labview. An offline analysis suite of image processing algorithms for automatically estimating pupillary and eyelid parameters were assessed using data obtained in human subjects. Our benchmark results show that such measurements can be done in a temporally precise way at a sampling frequency of up to 120 Hz and with an estimated maximum spatial resolution of 0.03 mm. Our software is made available free of charge to the scientific community, allowing end users to either use the software as is or modify it to suit their own needs.

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A low-cost, portable, micro-controlled device for multi-channel LED visual stimulation

Cited by 16 publications

References 25 publications

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

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

An inexpensive Arduino-based LED stimulator system for vision research

An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection

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