So the wellington bus service has implimented the "Snapper" card recently, and im kinda curious how it works. I'm guessing the Cards themselves are RFID, but how is it determining zones/distance fares? I suppose the driver could update this information en-route, but this seems unproductive towards an automated system. Does anyone have any technical details around the system and how it works?
There are a few forums around here that details the system. It's based of Korea's T-Money, it's a RFID system and uses high-level encryption.
You swipe the card to get on and must remember to swipe when you get off, the driver keeps beeping the zones into his console as he drives, is supposed to work of GPS but that feature is not operational yet apparently. * Someone confirm?
The minimum fare is deducted upon swipe on and the remainder (if any) is deducted at swipe off. if you forget to swipe off, the balance of the maximum fare for that journey will be deducted.
1. The cards are a smart card with an ISO14443 Type A radio interface.
2. It's highly secure - keys are generated for each transaction - can't be cracked a la MIFARE
3. The buses have all the routes and fare tables for all of the operators routes loaded into them. The driver selects the route and the fare tables particular to that route are loaded into the validators. From there GPS takes over. Each stop is recognised with X, Y and entry angle (for direction). At tag-on it recognises the stop, any concessions (eg cild or adult) and charges 1 zone minimum based where the stop is (eg city stops are only $1, other stops are $1.13 for an adult).Any penalities or catch ups for negative balance are also deducted at this point. At tag-off it reads where you boarded and calculates the difference based on the fare table. Drivers can adjust zones if they need to if they lose GPS. Drivers can also deal with multiple purchases etc etc.
Happy if any GZ'ers want to arrange a time to come in and have a yarn.