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The LocoMedia Footbridge Devices Project
Footbridge is an ultra-short range, wireless communication
mechanism. It will allow data rates of between 115kbps - 500kbps
to be transmitted over distances less than a foot (hence bad
pun!). We want to build three devices based on this technology:
- A bracelet or cuff-mounted footbridge transceiver that is
able to transmit and receive data from other FootBridge
devices. In the first instance we will use this to
achieve data transfer when cyberjacket users chake hands.
- A handheld display that displays output from the
CyberJacket when it is picked up.
- An information post (infoPost) that acts as a data server
for the delivery and storage of LocoMedia notes and for
other services such as web access.
The hardware for FootBridge is to be organised by Phil Neaves
at HP with help from Tom where feasible. This plan focusses on
the software issues.
Click here for the full Footbridge
Public health warning: reading this plan can induce
dizziness and nausea! Part of the work is to find a feasible
route to build this system. There are various options and it is
not yet clear which is best. Establishing this is part of the
work. Thanks to Chip McGuire, Dave Reynolds, Stuart Williams and
John Waters for stepping in to help plan this work. This plan is
likely to evolve further as our understanding of the issues
- Install mini web server on CyberJacket. Stripped down
Apache? The web-server may eventually be replaced with
something smaller and simpler.
- Get an HP320LX handheld PC to act as a web-terminal
connected to the web-server on the CyberJacket
- Develop software emulation for an unreliable serial link
and test on Linux system under a TCP/IP and PPP stack.
This will allow us to assess the potential to use
FootBridge in conjunction with a serial link.The
dependence of end-to-end performance on the error rate in
the serial link will tell us something about the level of
hardware error correction we would need to incorporate
into the Footbridge device. If these results are
encouraging then we may not need to develop an IrDA stack
solution. (see below)
- Phil to develop a FootBridge bench prototype.
- Install IrDA lite stack from irdalite.tar.
Read up enclosed documentation and examine code. Try to
understand lower (to IrDA device attached to serial port)
and upper (to PPP?) interfaces.Get it working.
- In case the IrDA lite solution does not work a partial
implementation of the full IrDA stack is available at http://www.cs.uit.no/~dagb/irda/irda.html.
This has the IrCOMM module missing so steps are:
- Read up on how to drive this stack. Email authors
- Acquire and compile source for IrCOM module.
Either Win95 version from sources in HP, or
preferably a unix style version from Chip
McGuire (who supplied IrDA lite) or via
Stuart Williams at HP (BSD Unix IrDA at UCL)?
- Configure software stack solution with IrDA device
acquired from http://www.extendsys.com.
- Check interworking of Linux and HP 320LX WinCE IrCOMM
stacks using infrared.
- Build Footbridge transceivers into system by removing
- Acquire Philip's Nino PalmPC from the US (Phil Stenton -
- Replace HP 320LX with PalmPC device.
- Check presence of appropriate web browser on PalmPC, else
attempt to download from Microsoft or ship across from
HandHeld PC using same microprocessor. Attempt to operate
browser in "full screen mode" - in this mode
there are many less control widgets on screen than usual.
- Design, and document a high level protocol to negotiate
between a range of Footbridge devices. Different devices
need to identify one another and allow invocation of
pre-defined functions on each end of the link. For
example, the handheld display must fire up the
web-browser and point it at an appropriate URL. At the
end of the session it must also close down the web
browser or some other appropriate action. User
handshaking and interaction with InfoPosts must also be
designed at this stage.
- Implement the protocol and hooks to other LocoMedia
modules on the CyberJacket. This software forms the
- Check interworking of two CyberJacket wearers when they
- Install a "Footbridge manager", communication
stack and Footbridge device on the note server.
Demonstrate interworking (exchange of LocoMedia objects).
- Develop an equivalent "Footbridge manager" for
the PalmPC running WinCE. Jim may do this at HPLB.
- Design and implement a note renderer that allows notes
held on the CyberJacket to be rendered on an available
display. Also install the renderer on the note server.
- Demonstrate interworking of handheld display and
- [extra activities if time is available!]Replace
web-server on the Cyberjacket with something smaller and
simpler. Henk and Jim to go over this.
- Plan and execute a solution for a wireless walk-up
display. This will be based around HP's infostations. Jim
to add details in due course!
- Build a digital camera using Footbridge to stores
images on your CyberJacket (and LocoMedia to make them
into LocoMedia objects). (definitiely after this Summer!)
The material displayed is
provided 'as is' and is subject to use restrictions.
For problems or questions regarding this web
contact Cliff Randell.
Last updated: January 14, 2000.
ęCopyright Hewlett-Packard 1997-2000.