BT in robotics

At 10:46 PM 6/2/2005, Bruce Hopkins wrote:
> Bruce,
>
> 1. True, Bluetooth is embedded in a lot of cellphones. But cellphones
> is not the only device that carries Bluetooth, as you already know.
> However, SonyEricsson has created the ROB1, which is a Linux robot
> that is controlled by Bluetooth, rolls around, and takes pictures.
> Take a look here:
> http://www.sonyericsson.com/rob1

They are obviously pretty serious about this product

> 2. Well, if Lego or JCX, was Bluetooth enabled, then it would be of
> some help to this group. I would love to carry in my pocket a remote
> contol (ie. a cell phone or PDA) for my lego robot. Almost every
> cellphone and PDA on the market has 4-way or 5-way navigation, so
> that's great for a robot remote control.

I'd love to have my cell phone give me status and feedback from my robots.

BT isn't the only way to do this, of course, and using the cellular data 
capability of the phone would allow connecting from around the world, not 
just within 10 meters.

> 3. The JB-22 is a Bluetooth development kit that allows Java
> developers to write Bluetooth applications between two PCs. The
> examples in the kit allow you to quickly get up to speed with device
> discovery, service searching, and two-way communication. However, this
> kit also allows you to communicate with other Bluetooth devices (that
> are not Java-enabled).  You can also use the libraries in the kit to
> write Java Bluetooth applications for JSR-82 cellphones.

Have you used this?

If so, what was your impression in an actual project?

> 4. This is no performance metric, but I've made cached connections
> from two Bluetooth enabled laptops (where I sent a file from the
> client to the server) in about 2-3 seconds.

The kind of embedded systems on which we are working need to authenticate 
and exchange a few bytes of data in low tens of msec, max. Zigbee claims to 
be able to do this. We will have some personal experience in a few weeks. 
We've been using 900 MHz RF modems from other vendors thus far.

> 6. If your cellphone or PDA supports J2ME, then it's end-user programmable.

I had high hopes for my T720, which does have J2ME. However TMobile chose 
to not support the serial port, so deploying and debugging apps is much 
more of a pain than it needs to be. It's way too klunky trying to enter a 
URL on the phone keypad.

So I gave up this idea and bought some Tungsten C (with 802.11b) instead. 
They also support Java, and other Tungstens have BT built in, or you can 
add a BT SD Card.

> Now, here's the potential for Lego and Bluetooth: I can create one (or
> many) custom Bluetooth services for my lego robot. My Bluetooth
> cellphone or PDA can discover, search for the services, and send data
> to the Lego robot. Since alot of other devces support Bluetooth, I can
> do things like:
>
> a. provide internet access to my robot (probably not on a CDMA network)
> b. send cool stuff from my phone (like text or pictures) to my robot
> c. grab Bluetooth GPS data and relay it to my robot
> d. the list goes on and on

This sounds great. You still have the 7-node BT limit right?

My personal bias is that Zigbee is better for the robot net communications. 
802.11 or BT would be better for communication with a PDA or phone.

We're pursuing the Zigbee approach.

But we'd love to collaborate with someone (you?) on a robot swarm with BT 
support, maybe through a PC bridge which has BT and Zigbee support?

Our current thinking is Zigbee on the swarm, with a local Java node (JStik 
for example) or notebook with Zigbee and 802.11 wired. Running JXTA on the 
robots and the notebook gives you a nice link from the robots to the 
internet. That's the grandiose plan, anyway.

Regards

Bruce