ubiq_uitous communication, wearable and multimedia systems

With the BTnode software running on both sides it is easy to setup flexible input devices that use Bluetooth for communication.

The photo has notes on Flickr.

A BTnode-alike sensor node can be made from individual modules. Just click on the picture - it has notes with additional infos at Flickr.

Will be used for prototyping the “Bluetooth enabled input device” (e.g. by translating from a PS/2 keyboard / mouse interface to Bluetooth) for a wearable computer.

It should be possible to run the BTnode software on a sensor node built by combining an Ethernut board (ATmega 128, 32k additional RAM) with an additional Bluetooth module.

With Bluetooth connectivity in place (for attaching additional input devices that extend touchscreen input) and an affordable Head Mounted Display (HMD) that is supported by the iPhone - things move forward towards a capable wearable computer.

This comes some years after the experiments with an iPAQ.

There is an updated video meanwhile.

Here is a short video showing the interacting devices (Apple wireless keyboard, iPhone, communicating over Bluetooth) in operation.

Feels like getting closer to the “mainstreaming” goal - it uses hardware that comes of the shelf (unfortunately you still need to have access to a jailbroken phone), uses a packaged application, does not expose bits and pieces to the end user, just works with all the applications that use the standard on-screen keyboard - and finally: it may just help you doing something more efficiently or comfortably.

It uses the Bluetooth stack developed by the researchers at ETH Zurich - they deserve all the credit.

They kept and keep continuing with the development of their BTnode software - so for a most recent version you should refer to the BTnode CVS repository. Everybody with a Linux or OSX desktop system can do his own experiments with the BTnode software in a setup like the one described under A Bluetooth stack in user space.

The work of the researchers at ETH Zurich basically had everything in place. All the credits go to them.

Just click on the picture for more information.

iPhone to iPod touch gaming via a wireless link. This video was done with the 2 devices interacting via WLAN.

There will be an update when we do this via Bluetooth.

We actually have Bluetooth connectivity - see screenshot below.

This is a data transfer (l2ping) over Bluetooth originated from a Linux system running Bluez to an iPhone using its built-in Bluetooth module.

Bluetooth development for the iPhone and the iPod touch join on the same path.

The screenshot below shows the whole setup in operation - it found another Bluetooth device in range.

An inquiry scan found another Bluetooth device in range.

00:18:42:e9:f8:ba is actually my N95 - as to be seen below

To be continued.

Just got this tiny projector.

Made by TI - interfaces to the beagleboard via a DVI-D cable.

A Bluetooth stack in user space already existed for quite a while. The researchers at ETH Zurich provide software for their BTnodes. A BTnode has (among other features) an ATmega 128 micro controler and a BT module with an HCI interface that is connected via a UART.

Fortunately, you can do development and real-world tests with just the same software compiled for running on a host system (e.g. PC). The emulator runs in user mode and uses a BT module attached to the serial port. Have a look at

• BTnut Unix Emulation
• BTnut System Software

for further info.

For experimenting with the sensor node software I used a module like this - which has a Mitsumi Bluetooth module with a CSR chipset, works at 115200 bps and could do hardware handshaking (RTS/CTS) - nevertheless - the jumpers on the board also allow to work with no handshaking at all (in case your serial port does not provide it) by looping RTS/CTS at the module side. The photo on Flickr has notes that explain the jumper settings.

I benefited a lot from having worked with Bluetooth on the HP iPAQ (Compaq at that time still) from the very early days - when this even still involved switching the HCI transport mode for the chip in the iPAQ with a tool provided by CSR. At that time I built a 2nd generation iPAQ based wearable computer for usage in a research project.

See the recent setup with the external adapter working on Linux.

After having tested it on a Linux system - I can confirm that the software works on OSX as well - run as a standard user with read/write access to /dev/tty.KeySerial1 (a Keyspan USA-19HS adapter).

Now - let us attach the (we are still talking about an external one) BT module to the iPhone serial port and compile / run the emulator program as just another user space program.

It just works (you will notice that - as shown on the photo on the top - I have 2 external modules - that’s the reason for the different MAC addresses).