I know there's a wealth of information on how to hack the Mindflex and Force Trainer game headset to access the EEG data they send out, so I am going to keep this brief, and try to make two points. If you are familiar with Arduino and soldering, this is a very easy hack.
First, I had not seen anyone using the Mindflex duel headsets that came out last year, and I just want to let everyone know that while the Mindflex duel and original Mindflex headsets look different on the outside, they are the same on the inside. I mention this because you can get the Mindflex duel game that comes with two headsets for less than the original Minflex game with one headset on Amazon these days. I was able to get the Minflex duel game, the FIO, and the Bee for less than $100 on Amazon.
Second I have some notes on how add Arduino and Bluetooth to the set, as seen on the next step.
Finally, I just wanted to let everyone know that I am using this headset as part of a much larger space based project called TRANQUILITY to control audio playback. You can learn more about it here. In the future I am hoping to build some binaural playback into the headset, and I'll put up a new instruct able for that soon.
Step 1: Hacking the set
What I wanted to do was fit the arduino into the headset, and have it communicating with my computer of Bluetooth. So I got the Arduino FIO board and Bluetooth Bee that fits into the FIO's xbee socket. I To get everything to kind of fit I made two mods, one to the FIO and one to the headset.
You have to program the FIO with an FTDI cable, the usb port is just on there to charge a LiPoly batter if you connect one. I am running the arduino off the headsets battery back, so I needed neither the usb port not the LiPoly plug, so I desoldered both of those. Be careful with the usb port because the FIO runs a necessary ground line through the usb port, so try to keep the solder pads intact. If your board doesn't work, it could be because this ground line got damaged; you can test it with a multimeter and see where it goes clearly on the FIO.
Next, I desoldered the big cap on the headset board and resoldered it in the same place on the other side of the board to make room for the Bluetooth Bee.
As for the wiring, connect the Arduino ground to the headset ground. For power I attached the Vin Arduino pin to the middle connector of the switch on the reverse of the headset board. This powers up the Arduino when the headset is turned on.
Now, to get the Arduino to send serial over Bluetooth it really needs both the RX and TX pins, so don't soldering the headset TX pin directly to the Arduino RX pin as you would if using usb serial. You've got to use a regular pin, I used digital 2, and use the new soft serial brain library, found in this branch on git hub. Every time I tried downloading that branch it downloaded the non-new soft serial version, so I just cut and pasted the text into new library files.
I put some female header pins on the FIO to make programing easy. You have to program it with FTDI first to add the Bluetooth code, and can't have the Bee in place when uploading cause it jams the serial port. You can see my code, attached.
Check out the photo notes, a picture is worth a thousand words in this case.
Step 2: Close it up
Now your ready so send your serial brain data to your computer without needing extra batteries, cables all over the place, or exposed Arduino boards. You can see how I used in TRANQUILITY.