The Wikipedia article on BCI
provides a very good summary of the current state of the art in Brain Computer Interfacing, what has been tried, how well various approaches work and gives some information re people and organisations involved in this work.
It seems that the use of non-invasive electrodes is te least likely method o work well -but it is the only one likely to be available to you. There are easier projects !.
Searching the internet for papers and information from researchers named on the Wikipedia page, who are doing what you want to do should be a good start.
In some cases contacting the researchers involved would be very useful. Some people are prepared to share in great detail. Some are not. Which is which you can find out by asking.
Here is a DOC file from Clarkson university by people attempting exactly what you wish to do BCI control of a wheelchair using skull electrodes.
Here is a brief Powerpoint presenttion by the same people.
Neither document provides enough detail to answer all your questions but shows what people are doing. They MAY be prepared to share their work with you.
You could consider investigating some of the BCI toys available. Wikipdia says:
Recently a number of companies have scaled back medical grade EEG technology (and in one case, NeuroSky, rebuilt the technology from the ground up) to create inexpensive BCIs. This technology has been built into toys and gaming devices; some of these toys have been extremely commercially successful like the NeuroSky and Mattel MindFlex.
In 2006 Sony patented a neural interface system allowing radio waves to affect signals in the neural cortex.[68]
In 2007 NeuroSky released the first affordable consumer based EEG along with the game NeuroBoy. This was also the first large scale EEG device to use dry sensor technology.[69]
In 2008 OCZ Technology developed device for use in video games relying primarily on electromyography.
In 2008 the Final Fantasy developer Square Enix announced that it was partnering with NeuroSky to create a game, Judecca.[70][71]
In 2009 Mattel partnered with NeuroSky to release the Mindflex, a game that used an EEG to steer a ball through an obstacle course. By far the best selling consumer based EEG to date.[70][72]
In 2009 Uncle Milton Industries partnered with NeuroSky to release the Star Wars Force Trainer, a game designed to create the illusion of possessing the force.[70][73]
In 2009 Emotiv released the EPOC, a 14 channel EEG device. The EPOC is the first commercial BCI to use dry sensor technology, which can be dampened with a saline solution for a better connection.[74]
