Category Archives: Mobile Devices

More on Wireless J2ME Applications with Java and Bluetooth

Java Developer’s Journal – Wireless J2ME Applications with Java and Bluetooth: “The oven is great at cooking, but bad at heating food quickly ­ and it’s also pretty expensive. Conversely, the microwave is cheap and great at heating food quickly, but it’s bad at cooking. Both devices have their trade-offs, although either could be used for heating and cooking. How does all this compare to wireless communication?

It’s pretty simple. Wireless LAN (802.11b) is good at connecting two relatively large devices with lots of power at high speeds. A good use of the technology is connecting two laptops at 11Mb/s. Wireless LAN is also good at connecting those devices at long distances (up to 300 ft).

Bluetooth is ideal if you want to connect small devices at slower speeds (1Mb/s) and within a shorter range (30 ft.). You can often find this technology on cheaper wireless headphones and even on higher performance devices like gaming peripherals. Why slower speeds? Isn’t faster better? Isn’t long-range communication a good thing? Not necessarily, especially when you consider the memory and power constraints on smaller devices. Faster connection speeds and longer communication ranges equate to larger power requirements. Why use an 11Mb/s connection if you’re transferring a 50K file between two PDAs?

One of Bluetooth’s strengths is its ability to function as a cable replacement technology. If you have multiple peripherals connected to your computer using RS-232 or USB, then Bluetooth is the ideal solution if you want to use those devices wirelessly. It’s difficult (if not impossible) to connect computer peripherals using 802.11b technology (except for printers). Bluetooth even has a built-in capability for wireless audio communication. To put things succinctly: Bluetooth will never replace 802.11b because it’s bad for:

  • Large file transfers between devices
  • Long-range communication

On the other hand, 802.11b will never replace Bluetooth because:

  • It can’t be used to communicate to peripherals.
  • It requires too much power for small devices.
  • It’s overkill for small data transfers.
  • It wasn’t designed for voice communication.

For the moment in the wireless communications arena, there’s no technology that’s best suited for every possible application. Either Bluetooth or 802.11b can be utilized for wireless communication between computers. Both have their place in the market, and both can perform remarkably well in their niches.

Wireless J2ME Applications with Java and Bluetooth

Java Developer’s Journal — Wireless J2ME Applications with Java and Bluetooth: “Let’s look at a scenario where life is made simpler using Java and Bluetooth technology: the Java Shared Whiteboard. Three employees of Acme Widgets Inc. need to have an impromptu meeting. Unfortunately, no conference rooms are available, so the team is forced to hold their meeting in the cafeteria. They would have preferred using a conference room because each room is equipped with an electronic whiteboard. However, since every member of the team has a Java Bluetooth-enabled PDA, their meeting in the cafeteria is very productive.

One member has a new program for his PDA called the Java Shared Whiteboard. Using Bluetooth technology, he sends that program to the rest of the team. Using Over-the-Air Provisioning (OTA) provided by J2ME, each member installs and runs the application on the fly. The meeting can now begin because the whiteboard is shared among the PDAs. Each participant can draw figures on his or her device and the image will appear instantly on the other screens. To save time, one member can take notes and send them to everyone’s device while the meeting is in progress.

Sony Ericsson T68i

I purchased the Sony Ericsson T68i for myself for Christmas (because after rebate it’s only $25 bucks!). I’ve been playing with it for the past couple days here in Mammoth while on vacation and so far I’m pretty impressed. I’d *really* love to get a BlueTooth enabled PDA (like the Toshiba e740 Pocket PC or the Palm Tungsten T Handheld or the Compaq iPAQ H3975 Color Pocket PC) so that I can do stuff like this or this.

The official Bluetooth site has a list of products using Bluetooth, although it’s kind of annoying to find that there are no URLs available for any product. I found a couple other Bluetooth specific sites/blogs including, Ericsson, The Bluetooth weblog but none of these sites has a listing of Bluetooth products. I want something like gizmodo for but Bluetooth (ie: tell me what fun Bluetooth products I can buy once I have the above mentioned phone!).

If you’re looking to write some Bluetooth code yourself, the following sites might be helpful:

JSR-000082 JavaTM APIs for Bluetooth

Microsoft Windows CE .NET Bluetooth