2 Wearable and Wireless Brain-Computer Interface Figure 1 shows the system diagram of the mobile and wireless brain-computer inter- face. The front-end unit integrates (1) clip on electrode holders for dry MEMS or commercially available wet EEG electrodes, (2) a DAQ unit, and (3) wireless- transmission circuitry, into a quickly and easily donned and doffed headband that can acquire and transmit EEG signals from up to eight channels. The back-end unit inte- grates a wireless signal receiver and on-line DSP. EEG signals are first acquired by dry MEMS or commercially available electrodes, amplified by the preamplifier, con- vented to digital signals, and then wirelessly transmitted to the data receiver. The DSP unit processes the EEG data and displays the results. The raw EEG data can also be wirelessly transmitted to a remote PC for further offline analysis and/or database collection.