These are some great DIY projects that you can do for cheap.
Learn how to repurpose your spare ESP32 boards into cost-effective presence detection sensors using the Tommy Sense ...
Abstract: Due to the objectivity of emotional expression in the central nervous system, EEG-based emotion recognition can effectively reflect humans' internal emotional states. In recent years, ...
Abstract: Brain-Computer Interface (BCI) is a revolutionary technique that employs wearable electroencephalography (EEG) sensors and artificial intelligence (AI) to monitor and decode brain activity.
It's amazing what you can do with an ESP32 (or two).