AVR-Chat

--- In AVR-Chat@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
> On Fri, 18 Feb 2005 19:26:17 -0000, Dave Mucha <dave_mucha@y...>  
> wrote:
> 
> >
> > IR would be fine, prefer to have extreemly close and not something
> > that would work more than an inch apart.
> > And, yes, each unit will have a battery.  Most likely a flat cell
> > phone batt or similar
> > Dave
> 
> 
> I think coils would be better then.
> My guts tell me it is easier to make it only work on close 
distances with  
> coils. Light doesn't work well that way i fear, in air.
> 
> Can you guarantee some sort of alignment, like, imagining the pack 
of  
> cards, that it would always lie flat and never stand on-edge? The 
RFID  
> systems seems to have big problems with alignment, so if you were 
to use  
> field strength as distance indicator you'd need to guarantee some  
> alignment. I think the coupling between two flat coils could be 
used well,  
> know the inductive-recharge contactless toothbrushes?
> 
> Sound might be another option, but can be disturbed by noise, 
depends on  
> what you are doing.
> 
> Electric contacts seem only reasonable if you can ensure 
positioning etc.
> 
> 
> ST

yes,  postioning and alignment can be guaranteed.  One option is to 
align them with dimples and to connect them with magnets.

Dave