NeuroStimDuino

An open source neurostimulator for students, researchers, and hobbyists interested in learning neuroscience

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NeuroStimDuino overcomes the challenges of delivering neurostimulation by providing an open-source stimulator in the form of an Arduino shield. It is designed for students, researchers, and hobbyists alike, to help them explore neuroscience by studying the effects of neurostimulation on muscle contraction.

NeuroStimDuino comes with an I2C interface to allow external microcontrollers such as Arduino Due to easily control its operation and generate different stimulation patterns. Each NeuroStimDuino shield has 2 independent output channels, which can be used to alternately contract flexor and extensor muscles or simultaneously contract multiple muscles. By stacking multiple such shields on top of each other, several output channels can be made available. It has built-in safety features which limit the power density generated by the stimulator to stay within the safety margins specified by the FDA.

What Is Neurostimulation?

Neurostimulation is the application of short electrical pulses on the surface of the skin to stimulate underlying nerves and muscles. In the last several decades neurostimulation has been used to stimulate muscles of patients with stroke and spinal cord injury, in order to assist and restore movement in their paralyzed limbs (also called Functional Electrical Stimulation or FES therapy).

Scientists and researchers have also used stimulation to study the effect of electrical current on neurons, particularly for pain reduction, sensory feedback, etc. Previously, neurostimulation could only be delivered using either research grade equipment that is expensive or has to be custom-built, which is challenging and time-consuming.

Features

  • Generates biphasic, rectangular and constant current stimulation pulses with programmable frequency, pulse-width, and amplitude
  • Stimulation pulses are charge-balanced, consisting of a cathodic phase followed by an anodic phase of equal or unequal amplitudes (i.e. waveform shape is selectable between symmetrical or asymmetrical)
  • NeuroStimDuino can be configured using I2C communication from an external microcontroller that acts as the Master controller
  • Onboard opto-isolators separate the digital and analog signals
  • Can be operated via a 9 V battery connected to DC Jack or by an external 5 V input on VIN. For proper operation, an external 9 V battery input is recommended
  • Onboard LEDs visually indicate the stimulus generation and a precision current sense amplifier gives a voltage output proportional to stimulation current
  • Safety features include fuses, solid-state relays to shunt inputs with low impedance resistors, and an emergency OFF switch
  • NeuroStimDuino board is supplied with a pair of 2 mm pin style lead wires to connect with standard, reusable, hydrogel-based stimulation electrodes. Additionally, a set of four 1.25” round and 2” square hydrogel electrodes and bifurcation cables are included in the NeuroStimDuino kit
  • For instructions and video tutorials on the placement of stimulation electrodes for evoking various hand and leg movements, please refer to https://www.axelgaard.com/Education (Courtesy: Dr. Lucinda Baker, Asso. Professor at USC (retired) and Axelgaard Manufacturing Co. Ltd.)

Specifications

  • Adjustable current output range +/- 25 mA, resolution 250 µA/step
  • Adjustable stimulation frequency range 1 – 100 Hz, pulse-width 0 – 2 ms
  • Maximum compliance voltage +/- 72 V
  • Onboard 16-bit dsPIC33F Microcontroller (40 MIPS, 256 KB flash memory), operates as an I2C secondary with programmable 7-bit address
  • Stimulation current output can be measured using onboard 12-bit ADC, or an external ADC

Demo

WARNING: This instrument is intended for RESEARCH PURPOSES ONLY. It is not intended for clinical or animal use. Neuralaxy LLC does not assume responsibility for injury or damage due to the misuse of this instrument.

See Also

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