Josh Koffman wrote:
>
> Olin Lathrop wrote:
> > I don't understand what one has to do with the other, and why an 802.11
> > interface precludes USB connectivity via a USB to serial chip.
>
> My read on that was that he's expected to use a consumer USB to 802.11
> adapter, made for use on a home computer or laptop. That might preclude
> the USB to serial chip as I'm not sure there are any that act as USB
> hosts. I could be wrong though. If I'm right, I don't envy him at all.

Unfortunately Josh, that is exactly what my boss expects. The people involved
see all these cheap WI-FI USB dongles that hang off USB ports, and figure that
is should be "relatively simple" to make it work with the current PIC
hardware. In other words, the want me to put a USB port on the unit so
they can plug in an 802.11 dongle. 'It's USB, right? It should just -work-'
I know better, but this is a collaboration with another large group,
and they have a lot of newly degreed engineers (as well as some older ones,
long since removed from hands-on design) who know all about the 'lastest
stuff'.
But since I don't have a degree, my experience/knowledge/skill means squat.

The FTDI chips will certainly make basic hardwired USB comms easy. The target
user will have a laptop, and probably won't have a real RS232 port today.
It's the TCP/IP stack and Wi-Fi handshaking that will be the killer if
I can't convince them it as bad an I idea as we all know it is.

I'm going to take the tact that if they think it is so easy to implement,
let them do it. I'll supply all relevant tech doc, and let them have at it.
Hopefully they'll believe me once they have to get their hands a bit dirty
coding. And 802.11 is way overkill just to get a wireless link. I'm hoping
to find something from Radiometrix, RFM or the like, but nothing I've seen so
far can touch the price of a 802.11b USB dongle. Of course they also neglect to note
that the dongle has to be attached to a $2000 laptop to be able to work, and that
you also need a wireless router too.

The problem is simple. RF wireless @ 19.2kbs full duplex to 150' and dirt cheap,
with the remote side the size of a silver dollar (3cm or so although
something the size of an eraser could be made to work as a 'clip on').
IR is not allowed because of line of sight and distance issues.
My unit is only the size of half a deck of cards, running on a AA cell boosted
to 3.3V, although 7.2V -may- become available in one variation.
So of course that tiny USB dongle is the 'perfect' solution...

There must be something COTS out there, I just haven't dug deep enough yet.
I'm thinking maybe wireless keyboard or mice if the intrinsic data
rate is high enough.

Thanks again for all the helpful ideas and feedback.
Especially Olin.

Let's put this thread to bed, and I'll let you know what I ultimately
end up with. Probably looking for a new job.

Robert

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