No, not hacking into the buses, but hacking better access to bus schedule info:
Greg Tracy has constructed an excellent API to access information about the Madison Metro bus system, including access to GPS-based real-time arrival information (http://www.smsmybus.com/
I've built a web-app that uses Greg's API to fetch real-time arrival info for a given stop and return it in a smart-phone-friendly format (though it also works fine in any regular browser as well).
In addition, I've worked out how to make a QR-code that calls my web-app: just point your smartphone's QR-reading app (there's lots of them out there) at the QR code and up comes the next N buses arriving at that stop, with real-time predicted arrival times.
My plan/hope is to find a way to deploy QR codes at bus stops, so people standing at a stop can know how long until the next bus actually arrives. And having done it once at a particular stop, they can bookmark the result and re-use it in the future, while still at home or in their office. Hopefully this would save people a lot of cold minutes standing at stops in the winter and some missed buses year-around...
So one could stick pre-printed post-it notes on bus stops:
qr bus code.jpg [ 46.69 KiB | Viewed 3362 times ]
Scanning this with your smartphone would return a page like this:
bus info .jpg [ 87.19 KiB | Viewed 3362 times ]
My next step is to contact Madison Metro's IT department to discuss a test deployment (seeking to avoid being considered graffiti or vandalism!). If they are amenable, I'll be looking for some volunteers to help create the post-its, deploy them en mass some day, and generate some pre-deployment publicity. Long-term, I'd like to get Metro to just print the QR codes on the paper schedules they post at many stops or make water-proof labels to put on sign posts at all stops...
Larry Walker (& Carol Bracewell, who came up with the QR post-it concept!)