Sunday, February 2, 2014

what is inside mind flex dual head set to reed eeg signals

Posted by rinson
   NeuroSky supplies the EEG chip and hardware for the Force Trainer and Mind Flex toys, these options represent a cheaper (if less convenient) way to get the same data. The silicon may be the same between the three, but our tests show that each runs slightly different firmware which accounts for some variations in data output. The Force Trainer, for example, doesn’t output EEG power band values — the Mind Flex does. The MindSet, unlike the toys, also gives you access to raw wave data. However, since we’d probably end up running an FFT on the wave anyway (and that’s essentially what the EEG power bands represent), we didn’t particularly miss this data in our work with the Mind Flex.
Given all of this, I think the Mind Flex represents a sweet spot on the price / performance curve. It gives you almost all of the data the Mind Set for less than half the cost. The hack and accompanying software presented below works fine for the Force Trainer as well, but you’ll end up with less data since the EEG power values are disabled in the Force Trainer’s firmware from the factory.
Of course, the Mind Flex is supposed to be a black-box toy, not an officially supported development platform — so in order to access the actual sensor data for use in other contexts, we’ll need to make some hardware modifications and write some software to help things along. Here’s how.
But first, the inevitable caveat: Use extreme caution when working with any kind of voltage around your brain, particularly when wall power is involved. The risks are small, but to be on the safe side you should only plug the Arduino + Mind Flex combo into a laptop running on batteries alone. (My thanks to Viadd for pointing out this risk in the comments.) Also, performing the modifications outlined below means that you’ll void your warranty. If you make a mistake you could damage the unit beyond repair. The modifications aren’t easily reversible, and they may interfere with the toy’s original ball-levitating functionality.
However, I’ve confirmed that when the hack is executed properly, the toy will continue to function — and perhaps more interestingly, you can skim data from the NeuroSky chip without interfering with gameplay. In this way, we’ve confirmed that the status lights and ball-levitating fan in the Mind Flex are simply mapped to the “Attention” value coming out of the NeuroSky chip.
 data by eric micca