Development of a functional electrical stimulation device for movement restoration in subjects with spinal cord injuries

Functional Electrical Stimulation serves as a promising approach for neurological rehabilitation; however, its adoption is often hindered by high costs and limitations in parameter customization. This research aims to overcome these barriers by creating an affordable, microcontroller-based FES device specifically designed to address foot drop. The innovative system employs a combination of ESP32 and ATmega328 microcontrollers paired with a DRV8876 driver, enabling the generation of precise biphasic pulses. The device operates effectively across a range of 0-360 microseconds for pulse width, 20-60Hz for frequency, and 0-167mA for amplitude. laboratory validation has been carried out using oscilloscopes and multimeters, confirming the accurate generation of the desired stimulation parameters. Additionally, simulations conducted with MATLAB Simulink and Proteus further validate the hardware performance. To enhance user comfort, a user-friendly GUI and a companion Android mobile application have been developed. These interfaces facilitate parameter adjustment for user-centric feedback and the logging of patient session data, with information securely stored in a local database to ensure privacy. The system incorporates AES encrypted data transmitted via the BLE capabilities of the ESP32, offering flexibility. Notably, this design achieves a 20% cost reduction with enhance features compared to existing foot drop FES systems within its price range and an extended battery life of 24 hours double the operational duration of similar devices. This newly developed FES system represents a functional and economically viable solution for foot drop rehabilitation (Dorsiflexion, Plantarflexion, Ankle Rotation and Toe Extension), thus paving the way for greater accessibility for personalized FES therapy.