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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:

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 paper.


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 improves.

  1. Install mini web server on CyberJacket. Stripped down Apache? The web-server may eventually be replaced with something smaller and simpler.
  2. Get an HP320LX handheld PC to act as a web-terminal connected to the web-server on the CyberJacket
  3. 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)
  4. Phil to develop a FootBridge bench prototype.
  5. 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.
  6. In case the IrDA lite solution does not work a partial implementation of the full IrDA stack is available at This has the IrCOMM module missing so steps are:
    1. Read up on how to drive this stack. Email authors as necessary.
    2. 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)?
  7. Configure software stack solution with IrDA device acquired from
  8. Check interworking of Linux and HP 320LX WinCE IrCOMM stacks using infrared.
  9. Build Footbridge transceivers into system by removing LEDs.
  10. Acquire Philip's Nino PalmPC from the US (Phil Stenton - 17/7/97)
  11. Replace HP 320LX with PalmPC device.
  12. 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.
  13. 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.
  14. Implement the protocol and hooks to other LocoMedia modules on the CyberJacket. This software forms the "Footbridge manager".
  15. Check interworking of two CyberJacket wearers when they shake hands.
  16. Install a "Footbridge manager", communication stack and Footbridge device on the note server. Demonstrate interworking (exchange of LocoMedia objects).
  17. Develop an equivalent "Footbridge manager" for the PalmPC running WinCE. Jim may do this at HPLB.
  18. 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.
  19. Demonstrate interworking of handheld display and Cyberjacket.
  20. [extra activities if time is available!]Replace web-server on the Cyberjacket with something smaller and simpler. Henk and Jim to go over this.
  21. 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!
  22. Build a digital camera using Footbridge to stores images on your CyberJacket (and LocoMedia to make them into LocoMedia objects). (definitiely after this Summer!)

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Last updated: January 14, 2000.
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