Do want to use Linux together with your bicycle? Here is an overview of free software and open hardware.
srmio(http://www.zuto.de/project/srmio/) is a library to access the most important functions of a Schoberer Radmesstechnik (SRM) PowerControl V bike computer. You can download the data, mark it deleted, sync the time, and set the recording interval. To be as compatible as possible, it reads (SRM6/SRM7) and writes (SRM7) files in the same format that srmwin uses.
HAC4Linux(http://hac4linux.sourceforge.net/scripts/desktop.php) is a GPL application for bicycle computers of different manufactures.
Spokeculator Evo 3(http://spokeculator.sourceforge.net/) is a GPL'd tool helping bicycle mechanics and wheelbuilders to calculate the lengths of spokes. It includes a database for rims and hubs.
Bicycle Ride Calorie Calculator(http://www.geocities.com/SiliconValley/Vista/6434/calcalc.html) is a simple program that calculates the number of calories expended on a bicycle ride. It is based on an article in the May 1989 issue of Bicycling Magazine, pp. 100-103. It provides a good estimate of the number of calories burned based on time, distance, rider weight, wind speed and direction, drafting, and climbing. It is not meant to be a completely accurate calculator and playing with the input values will reveal that the equations break down for very small and very large average speed values. Calorie expediture values seem very reasonable for average speeds between 5 and 30 mph. There are three version of the software. The Linux version was written in C++ using the FLTK widget library. The OS/2 version was written in REXX using version 3 of VisProREXX. The Java version was written a while back using version 1.02 of the JDK.
VeloAce(http://www.engbedded.com/veloace) is an Open Source bike computer with logging and training functionality for Palm OS.
Yahoo! Maps Bike Accidents Administrator(http://strans.org/hotspots/) is a simple Web-based application for managing bicycle accidents online. It uses Yahoo! Maps. It allows the user to add, edit, delete, or export records and provides a map interface. It could be adapted for real estate easily.
BBBike(http://www.bbbike.de/cgi-bin/bbbike.cgi) is a Perl program which seeks for bicycle tours in Berlin and Potsdam (Germany). Almost all streets of Berlin and Potsdam are included in the database, they are searchable by different categories (main street, usable with trailer, etc.).
BikePower(http://search.cpan.org/search?mode=module&query=BikePower) is a bicycle power-output calculator with command-line and Tk interface written in Perl by Slaven Rezic.
BikeCAD(http://www.bikeforest.com/CAD/linux_mac_windows.php) is a parametric CAD tool for bicycle frame design. The Bicycle Forest has created several variations of this program to accommodate specific designs and tasks such as recumbents, full suspension, tandems, and wheel building. BikeCAD can run on any operating system. All you need to do is ensure that Java is installed. If you can run the free version of BikeCAD, then you should be able to run BikeCAD Pro as well.
This whitepaper explains how to use Java and Linux to capture real-time data(http://www.ibm.com/developerworks/data/library/techarticle/dm-0803lurie/) from an exercise bike and transform it into an Informix or DB2 database. There are also some notes on building the hardware from a computer mouse and a Zeemote Bluetooth wireless device (game controller).
MyTourBook(http://mytourbook.sourceforge.net/) is free software to visualize and analyze tours which are recorded by a GPS device, bike- or exercise computer and ergometer, it can: transfer, import, export, edit and visualize tours, compare tours automatically, segment a tour automatically, do statistical analysis and manage tours for different people. It runs on different platforms Linux , Mac , MS-Windows.
Pytrainer(http://pytrainer.e-oss.net/index.php) is a tool to log all your sport excursions. It is originally programed for cyclists, but it can be used for any other type of sports. It offers routes and excursions statistics log, Googlemaps integration to display GPS tracks, viewer and editor of waypoints integrated, plugin system for multiple GPS devices and more.
SportsTracker(http://www.saring.de/sportstracker/index.html) is an application for people which want to record their sporting activities. It is not bound to a specific kind of sport, the user can create categories for all sport types such as cycling, running, swimming or tennis. The main advantage is a good overview of your exercises and you can easily create diagrams and statistics for specific time ranges and sport types. In the calendar you can also track your body weight or create note entries, e.g. the training plan or upcoming sport events. All the application data is stored in XML files. So it should be easy to access it with other tools or to write importers and exporters for other applications. If you own a heartrate monitor with a computer interface you can display the recorded exercise files and evaluate the diagrams with the integrated PolarViewer application. You can organize them by attaching the recorded files to the exercise entries. When adding new exercises you can import the data from the recorded exercise files.
The open bicycle computer (obico)(http://obico.de/) is an outdoor computer that primary is constructed to show and log data that are important when you are on the road with your bicycle. Obico can either log your daily training data or it can be used to log your bicycle tour data over several days. Obico comes with a predefined software that allows you to use the features of this computer without writing your own programs. You can write your own programs for obico, but you don't have to.
Navigators are rather power-hungry: typical operating times with an illuminated display are a few hours. On the other hand, the power potential of the dynamo hub would be wasted when light is not needed. On long bike journeys, it would be very useful to supply power to the navigator from the dynamo hub. Here is a schematic diagram for a cheap low-dropout rectifier and linear regulator(http://www.ktverkko.fi/~msmakela/electronics/dynamo5v/) , a bill of materials (aka parts list) and circuit board layouts.