A modular portable current stimulator for electrical stimulation of excitable tissues

Electrical stimulation can be applied to excitable tissues to obtain sensory feedback, as in the case of stimulation of the peripheral nervous system, or mechanical actuation, as in the case of the stimulation of muscle tissues. In this study, a current stimulator for the stimulation of excitable tissues is proposed. The stimulator, created using a “stacked” approach, is made up of three separable units, namely a microcontroller unit, a stimulation frontend unit, and a power unit. The stimulator, made with Components-Off-the-Shelf (COTS), guarantees a working voltage of up to ±90 V and a stimulation current of up to 18 mA. The system has been tested for the stimulation of the peripheral nervous system on healthy volunteers, making it capable of inducing distinguishable sensations in the lower limb and on the upper limb, both through the use of conventional electrodes and ultra-conformable tattoo electrodes. Furthermore, the stimulator was tested for the control of a biohybrid actuator made up of muscle tissues showing the possibility of inducing twitch and tetanic contraction.