Ben-WPAN Overview

Ben-WPAN is a hardware and software effort within the Qi-Hardware project. The objective is to enable the Ben NanoNote to communicate wirelessly using IEEE 802.15.4-based protocols.
All elements of the project are licensed under open licenses, such as the GPLv2+, LGPLv2.1+, and CC-BY-SA 3.0. Furthermore, only Free tools were used for the electronic design, such as the GPL-licensed Kicad.
This page is a brief summary. For background information and further details, please visit the wiki page.

A first run of atben and atusb boards has been produced by Tuxbrain S.L. and is available for sale.

atben (for the Ben NanoNote) atusb (Full-Speed USB)

Hardware

Both boards are based on the Atmel AT86RF231 transceiver. They operate in the license-free 2.4 GHz band using the IEEE 802.15.4 physical and link layer.
Note that IEEE 802.15.4 is different from IEEE 802.11 (WLAN) and IEEE 802.15.1 (Bluetooth).

Both boards transmit with a maximum power of 2 mW (+3 dBm) over a distance of up to about 10 m in a typical indoors environment.
The standard data rate of IEEE 802.15.4 is 250 kbps. The transceiver supports non-standard rates of up to 2 Mbps, with a reduced range.

Compatibility

atben and atusb can communicate at the physical and link layer with any device that implements the IEEE 802.15.4-2006 standard for the 2.4 GHz band.
This includes atben with atusb, atben with atben, etc. There are many more IEEE 802.15.4 devices, which should also interoperate with the Ben-WPAN boards.

atben plugs into the Ben's 8:10 card slot. Note that it is not an SDIO card.

atusb is designed for USB 2.0 Full-Speed and has an USB A connector. The host needs suitable drivers for the board.

Software

The ultimate goal is to fully support IPv6 with 6LoWPAN, in cooperation with the linux-zigbee project. This work is still in progress and may take a while.

To make use of the boards while working on IPv6, we have developed a quick and dirty tunnelling mechanism for IPv4. A video demonstrating its use can be seen here.

atben has no local "intelligence" and its SPI interface is bit-banged directly by the Ben.
atusb uses an Atmel ATmega32U2 microcontroller to interface between USB and SPI with a homebrewn protocol on top of USB.
The firmware includes a boot loader allowing easy firmware updates in the field with the DFU protocol.
This boot loader occupies 4 kB of the 32 kB of Flash memory in atusb. The "application" uses another 6 kB. Developers wishing to extend or replace the firmware thus have between 22 and 28 kB available for experiments.

While not an immediate project goal, it may be possible to write firmware for atusb that turns it into a transparent gateway for legacy operating systems and protocols.

Status and resources

Here is an overview of the status of the various project elements:

ElementStatusLinks
SchematicsDone atben, atusb
LayoutDone atben, atusb
Test softwareDone scripts, tools, description
ProductionDone Production notes
Firmware Finishing source
Device driver In progress linux-zigbee project, ben-wpan kernel branch
MAC layer In progress linux-zigbee project
IPv4 hackDone dirtpan
6LoWPAN stackTo do

Further reading

We have a more detailed wiki page.
Discussions related to the project take place on the Qi-Hardware mailing list and on the #qi-hardware channel on freenode.
Tuxbrain have a description with additional pictures and a link to their shop.

Last update: 2011-06-15   Werner Almesberger