Hi,
We're trying to stay away from the shield design format because of safety issues. There's too much liability involved when you allow someone to attach a piece of metal to their body that could be connected also to the mains power. It is possible to isolate against this problem and we have made every effort to isolate. (current V2 design has 2.5kV isolation) but it is still untested, and in order to test the cost is prohibitive. Our best direction is to go with a battery powered wireless design.
How many expansion boards can be attached to a main board? For example if I want to collect full cap 19 channel data, I'll need 3 ADS1299 chips (main board and two expanders). I know you support daisy chaining, but are there any considerations as far as data transmission speed on your Bluetooth link? Typical commercial 19 channel amps do 512 samples/sec and 24 bit samples. I think I read somewhere that Bluetooth low power has a corresponding low data rate.
After recording such data, it can be analyzed by normative databases such as Neuroguide or NewMindMaps, which I have used in the past with <a href="http://www.brainmaster.com/kb/entry/349/">Brainmaster Discovery</a>, a 24 ch amp connected via USB.
Could you allow an optional USB connection mode for those wanting to avoid Bluetooth? I suppose I could do this myself if there was something like a usb shield / libraries.
For those interested, here is a <a href="http://e2e.ti.com/search/default.aspx#q=1299&g=45&sc=forum">link to the Forum</a> at Texas Instruments with posts on the ADS1299 EEG chip. Many of these are using it with the clunky TI Eval board, which is way unwieldy compared to what OpenBCI is doing. But there are a range of questions and responses on various hardware functions.
Comments
We're trying to stay away from the shield design format because of safety issues. There's too much liability involved when you allow someone to attach a piece of metal to their body that could be connected also to the mains power. It is possible to isolate against this problem and we have made every effort to isolate. (current V2 design has 2.5kV isolation) but it is still untested, and in order to test the cost is prohibitive. Our best direction is to go with a battery powered wireless design.
After recording such data, it can be analyzed by normative databases such as Neuroguide or NewMindMaps, which I have used in the past with <a href="http://www.brainmaster.com/kb/entry/349/">Brainmaster Discovery</a>, a 24 ch amp connected via USB.
Could you allow an optional USB connection mode for those wanting to avoid Bluetooth? I suppose I could do this myself if there was something like a usb shield / libraries.
--William Croft
You will be able to stack and stack and stack if you want.
The connections will allow for that, and of course, it will be hackable!
Joel