Manhole Transceiver - KYT = Kill Your Television

What's this?

Questions?

What's the point?

It eliminates the discovery-and-pairing from Bluetooth. Basically it solves the save problem as what is address by Bump. I just thought it sits naturally in mind that you take picture of something and its data is stored in the local memory.

How does it work?

1. The sender side specifies the file to send. Then the manhole symbol encoding sender's Bluetooth address appears on the screen. The server starts a server and waits for the receiver to connect.

2. The receiver side captures this symbol and demodulates the address. With this address, it connects to sender's server.

3. Once connected, the file is transferred over the Bluetooth connection.

Did you write this program?

Yes, the application layer is entirely our own code.

For the Bluetooth API, we've gratefully took benefit of Bluecove and Backport Android Bluetooth.

What are you cheating?

A few things. First, the current Android's Bluetooth API doesn't allow RFCOMM channel be created without pairing. So in this demo video, the PC and mobiles are already paired. That really defeats the purpose of using Manhole transceiver! Another thing that might count near-cheating is the lighting condition. You can see the room is somewhat dark in this video. This was mainly for my digital camera to make nicer picture. But it also means easier condition for the image processing. Anyway, it has been working okay with the room light.

iPhone is cooler

I know. And T was going to do the iPhone version too (he has purchased the developer program). But the thing is iPhone doesn't really allow SPP connection to span with a device other than iPhone. We gave up.

How about Symbian?

Good point. Symbian users should actually be the ones who benefit from this kind of technology. iPhone and Android users are typically subscribing a flat-rate data plan, which opens the options for other cool solutions like dropbox. And Android users are typically more technology oriented that they can handle the Bluetooth discovery-and-paring (though it is a pain).

I did have developed the Symbian version. In fact, I had made the Symbian version in prior to the Android version. It works but have certain disadvantages. Most of the Symbian phones out there don't support the API necessary for accessing camera auto-focusing; it is the same API that allows me to turn off the flash so that I can avoid the glare on target screen. And what is more demotivating is the security policy it has. To overcome, I must rewrite the program with Symbian C++ and purchase the certificate, which costs several hundred bucks a year. Oh my Budda, I gave up.

Why not QR code?

By now, you've probably realized we were planning to make this technology available across many more platforms (but couldn't). So we've need the modulating symbol to be available in all platform. Writing a QR code codec is one solution. It's tempting but a hassle. Besides, we've just needed to transfer 7 bytes containing the Bluetooth address and service channel. So we've decided to make our own scheme. At least I think our symbol looks more psychedelic and hip!

• てす -- (K) 2010-06-26 14:55:08