Re: TINI wireless link - IR or RF?

How about bluetooth?  There are a number of pure Java BlueTooth stacks  
(hit "java bluetooth" at sourceforge).  There's even one targeted at  
the TINI:

http://www.javabluetooth.org/

Jim

On 06/29/04 10:28:00, Bruce Boyes wrote:
> At 10:27 AM 6/29/2004 +0100, Simon Melhuish wrote:
>> Hi.
>> 
>> I've been given with an urgent interfacing job, that will require  
>> communicating wirelessly with a battery-powered TINI (or similar).  
>> Can anyone suggest where I should start?
>> 
>> The basic requirement is short range (< 3m) so I'm thinking IR. Also  
>> it's going to be pretty dark (South Pole during the winter) which I  
>> suppose may help. If I went RF I'd have to take care about  
>> interference. The data rate need not be high (say 9600 Baud), but  
>> should be bidirectional.
> 
> Short range RF or special long range IrDA might work. IrDA is only 1  
> meter guaranteed and the angle is quite narrow, something like 10 or  
> 15 degrees in a cone. RF could be 360 degrees of coverage.
> 
> RF is typically by nature half duplex. So a 19200 baud modem might  
> work depending on your data packet size and rate. 9600 baud is 960  
> bytes/sec max. Any packet overhead cuts this down.
> 
> RF modems need some few msec to switch from transmit to receive, too,  
> and have some overhead with preamble, CRC, etc, just like ethernet.
> 
> 
>> I've seen some mention of irDA on this list in the past, but most  
>> often as a work in progress. Can anyone tell me of any off-the-shelf  
>> ready-to-go gear for this kind of thing? I need to have something  
>> running by Christmas at the latest.
> 
> IrDA doesn't have the range you need. It's 1 meter by the spec.
> 
> You can buy the modems today from Maxstream, and their dev kit with  
> serial interfaces. We will have JSimm carrier boards soon after JCX  
> is really shipping. But the dev kit from Maxstream.net works great  
> and will do everything you need.
> 
> You could cook up your own IR serial link with stronger transmitters  
> (or buy some off the shelf, non- IrDA) or use fiber optics running  
> through a sealed wall?
> 
> It's not clear to me what the constraints are in your system.
> 
> Regards
> 
> Bruce
> 
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-- 
Jim Redman
(505) 662 5156 x85
http://www.ergotech.com
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