Re: [buildcheapeeg] Re: Building an EEG

From: Doug Sutherland (wearable_at_earthlink.net)
Date: 2001-11-25 19:35:13


Hi Laura,

I'm curious why there seems to be so much interest in iRDA
for EEG data comms. I assume that you want a wireless link,
but you've already got wires everywhere (electrodes) and
you need to be in close proximity to the PC anyways if you
want to get any feedback. So it seems to me that the only
benefit of irDA is not having to having to plug in one cable,
or just having ability to record (not train) untethered.
Won't most usage of the EEG require sitting in front of the
PC anyways?

Another possibility re cheap wireless for EEG is the small
RF transceivers. These are cheap these days, would provide
a better RF link, and would probably be easier to program
too. Some of them are spread spectrum, they can transmit
through walls. Another idea is to bolt an embedded PC right
onto the EEG, that makes more sense to me, then you can do
802.11 or even CDPD or CDMA/GSM if you want to send the
data elsewhere.

-- Doug

ldean_at_metrowerks.com wrote:

> --- In buildcheapeeg_at_yahoogroups.com, "Moritz von Buttlar" <info_at_baltic-microsolutions.de> wrote:
> > I'm still thinking about an IrDA EEG device, using some kind of
> simple IrDA software protocol and IrDA hardware. Maybe you could find
> out if it's possible to get some simplified protocol working using
> IrDA hardware ?
>
> I have been looking into IrDA for EEG. There is a simplified protocol
> called IrDA Lite which represents the bare minimum needed to comply
> with the IrDA standard. IrDA Lite limits the baud rate to 9600 and
> limits packet size to 64 bytes.
>
> It is still not simple, IrDA requires several protocol layers
> including hardware, driver/framer, link access protocol, link
> management protocol, and transport protocol. I have been unable to
> find any open source c code implementing IrDA lite for a secondary
> device. Additionally, I assume there will need to be work done on the
> PC side so that the ElectricGuru (or whatever) software can interpret
> the IrDA signal.
>
> For the hardware, several companies manufacture IrDA transceivers.
> The driver/framer would be microcontroller specific, but I think the
> rest of the code could be written in C and would be fairly portable.
> I am willing to do some work on the firmware, but I would be working
> on a 68HC12.
>
> Laura



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