Wireless bi-directional data link for an EEG recording system using STM32

A wireless bi-directional data link for an electroencephalogram (EEG) recording system is presented in this paper. The system is mainly composed of a prototype model of an implant and a data recorder. Both the implant and the data recorder use STM32 microcontrollers with an inbuilt radio frequency (RF) transceiver to establish a wireless link between them. The main component of the implant is a mixed-signal EEG acquisition ASIC with 8 channels. The STM32 and the ASIC of the implant module communicate via two SPI interfaces. Optimized software codes for the STM32 microcontrollers have been written to ensure a reliable wireless communication between the implant and the data recorder. A PC is connected to the data recorder which enables the communication by sending the configuration data to the implant. The data received by the data recorder is stored in a PC. The amount of input referred noise of the ASIC present in the output is estimated with the help of MATLAB.