Pebbles: Practical Results and Achievements So Far

See the pubs page for formal results.


  • Henry has written Pebbles for the RSS feed and TV programme schedule (useful for TiVo demo) and also a generic WSDL to Pebble conversion.

  • David has implemented a simple HLL called Pushlogic for embedded scripting and feature interaction checking.

  • Tope has completed another form of rule based controller and generated several short position papers.

  • Daniel has completed porting the Pebbles software to the Molly cards and has built several hardware Pebbles (clock, DVD player, LCD display and so on). He has got Pushlogic working on these cards and now developing some network applications.

  • We manned a Pebbles stand at the CMI show held in the Gates building in April 2004 and again in 2005.

  • In general, we are putting together an ever growing number of Pebbles and the applications are following on.

    The next steps will be further publications and dissemination to industry through CMI.

    Further details of the above

    Rule Based Controllers

  • Position Paper - Ideas for a Predicate Calculus Rule Based Controller - Unpublished.

  • ML Prototype Implementation of a Rule Based Controller using SAT solver.

  • Prolog and C# Implementation of a Rule Based Controller (RBC)


  • Documentation on Locally Constructed Pebbles.

  • Embedded Pebble Cards: Mollies.

  • O2S Registry Running on Local Machine SAND

  • Shared CVS code repository between the two sites.

    Pushlogic Related

  • Embedded Tuple Core and Push Logic Interpreter runs on Unix

  • Embedded Tuple Core and Push Logic Interpreter runs on a Molly

  • Push Logic Compiler Version 1 basically works but load time checks not implemented yet.

  • Semantics of Push Logic - report in progress

  • EPSRC Research proposal to take this further drafted.

    Software Pebbles Constructed

  • OS2 Pebble Protocol to XML RPC proxy for the XML RPC Alarm Clock

  • SICS LWIP Lightweight TCP/IP etc working on a Molly

  • Media Server Pebble - Implemented on Linux Workstation

  • Audio Playback/Record Pebble - Implemented on Linux Workstation

  • Speech Synthesiser Pebble - Implemented on Linux Workstation

  • Speech Recogniser Pebble - Implemented on Linux Workstation

    Harware Pebbles Constructed

  • UDP Controlled Pebbles: Lamp, Light Switch,

  • Piggybank XML RPC Pebble

  • One Hardware Pebble Prototype Implemented on a raw PC Motherboard

  • Alarm Clock Pebble implemented with XML RPC and then with O2S.

  • Heating Controller (for install at DJG's house!)

    Proxies Written

  • CGI-like Python Stub Set Written - allows ML RBC and so on to talk to O2S Pebbles and Registry

  • Pebble Generator from WSDL wraps any Web Service as a Pebble.


  • A complete embedding of UPnP in UML is complete.

  • Scripting/programming research proposal written.

  • Tope has implemented some natural language and speech-driven rules.

  • Hague's media cube work ?

    Minor Docs

  • Security Note Written.


  • The O2S Pebble protocol does not work well through the Computer Laboratory firewall at the University of Cambridge.
  • Pebbles offer an API and describe themselves to their environment, but do not perform proactive operations on their peers. They are pretty passive really.

    END.       Pebbles Main Page.