BlueTooth bad, Zigbee good

At 07:47 PM 5/31/2005, Steve Baker wrote:
>>Bluetooth is a very versatile RF-communication that could allow real flexible
>>networking for multi-agent applications. This would be a much faster
>>communication than slow IR.
>
>Bluetooth has a maximum range of 30 feet.  That's in optimum conditions.
>You might get down as low as 15 feet in real world applications.  At 2GHz
>or so, it doesn't go through walls very well either.

Bluetooth is actually very poor for embedded or robotic applications. It's 
a power hog, development tools are expensive (try $5000 minimum), true peer 
to peer modules are almost impossible to get unless you are a Fortune 500 
company, and the time required for a BT node to wake up, authenticate, and 
transmit data is very long. BT is also overly complex for most embedded or 
robotic applications. The range of 30 feet is not great either.

So what is OK?

Zigbee is much newer and is designed for use with embedded and robotic 
applications. The time required for a Zigbee node to wake up, authenticate, 
and transmit data is very short - less than 1/10 that of BT. Power 
consumption is much less, and range can be 100 feet or more, depending on 
antenna design and other factors. Tools are very affordable (sometimes 
free) and dev kits are $300 or less.

There is a Zigbee alliance with a lot of major companies such as Motorola, 
Samsung, Philips, etc:
http://www.zigbee.org/en/about/members.asp

Also get this white paper: "ZigBee and Bluetooth: Competitive or 
Complementary?" at
http://www.zigbee.org/en/resources/#WhitePapers

We are designing a Zigbee node for use with JCX, (which will finally start 
shipping this June/July after almost 4 years of development and testing). 
We are planning on using the Freescale Zigbee chip MC13192. We have a 
couple of their dev kits which were about $300.
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC13192&nodeId=01752003088166

Properly designed Zigbee nodes can interoperate. What about BT? Vendors are 
deliberately designing some BT products (such as cell phone headsets in 
particular) so they don't interoperate for "competitive reasons". Pretty 
dumb, huh?

The "BlueTooth" serial adapters which are available, and which most people 
point to as BT for embedded use are a very hacked-down subset of BT and are 
not generally useful. They support only two devices per network, with only 
serial conversion. They are only useful for short range serial comm between 
two devices, nothing more.

You can get started with Zigbee nodes from Mouser:
http://www.mouser.com/dlpdesign/

So to sum up, forget BT for robotics. Use Zigbee.

Regards

Bruce


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