NeuroSky Inc. wants to get into your head. By fusing brain wave recognition algorithms with a sensor chip and dry electrode, NeuroSky hopes to simplify cell phone-based applications that today require error-prone human input, as well as revolutionize applications from gaming to medical diagnostics and therapy. Conventional EEGs require the use of greasy paste to reduce the impedance between an electrode and a person's skin, but NeuroSky's dry electrode just needs to touch the forehead via a pod that can be attached to virtually any headset. Five companies, including a Bluetooth headset provider, game console maker and trucking company, are said to have signed up to market end-user products containing NeuroSky's chips. Its biggest customer thus far is Ziyitong Technology Co. Ltd. (China Mobile), which has more than 100 million cell phone subscribers, 13 million of whom have high-speed 3G service.