The first Kotibussi demo used the very basic ENC28J60 Ethernet controller based ethernet shield. That means the TCP/IP stack had to be run on the Arduino itself, taking up a lot of precious memory. I'm moving it now over to a WizNet W5200 based shield that takes care of the TCP/IP stack in hardware for me, makes a ton of difference in the amount of memory I now have to play with.
Some ideas are to have an integrated RTC and some way to configure the device without re-flashing, aka some control buttons and menu system, the added memory helps a ton in this.
And the backend. Luckily there is a standard for M2M transport data, Siri, unfortunately it is not well suited for low-bandwidth/low-speed/low-memory devices as it is XML based and extremely verbose. And it is also pull based so I would need to poll the data and that is just stupid.
So a Siri2MQTT gateway needs to be created, some minor progress in there, just a skeleton for now but getting there.
Then there is the minor issue that Turku does not provide any data yet (no timetable, they hope to get it open in 2015), luckily some cities in Finland aren't that behind in progress so I will use Tampere Public Transport SIRI service for now.