We propose a novel behind-the-ear wearable device for microsleep detection, called WAKE. WAKE detects microsleep by monitoring biosignals from the brain, eye movements, facial muscle contractions, and sweat gland activities from behind the user’s ears. In particular, we introduce a Three-fold Cascaded Amplifying (3CA) technique to tame the motion artifacts and environmental noises for capturing high fidelity signals. The behind-the-ear form factor is motivated by the fact that bone-conductance headphones, which are worn around the ear, are becoming widely used. This technology trend gives us an opportunity to enable a wide range of cognitive monitoring and improvement applications by integrating more sensing and actuating functionality into the ear-phone, making it a smarter one.