Genevieve Hoffman
Paul May
Stepan Boltalin


A charity donation platform using New York City subway cards.

Urban Experience in the Network Age

Every year, millions of dollars worth of value on MTA MetroCards is lost or discarded.<br /><br /> MetroChange takes this value and puts it to good use, before cards are discarded. Swipe your MetroCard at a MetroChange kiosk; the value on the card is transferred to a central fund. This fund is donated to a charity once per month. The physical card is taken for recycling.<br /><br /> Since there is usually up to $2 left on MTA Metrocards (partially thanks to the MTA 7% bonus), the overall waste from the leftover money and lost cards accumulates to $52 million a year. MetroChange is designed to raise awareness of this and suggest a platform for channeling the money that people are discarding to serve a good cause.

We have done a lot of research on how magnetic stripes work and were able to port the Metrocard decryption protocol from a windows machine to Arduino, so that now it is possible to read values off MTA Metrocards and show how much money is left.

Anybody who has ever found that he or she has $1.70 left on MTA card and there is no way this change will be ever used. We believe that tourists will be more likely to use Pay Per Ride cards, so we anticipate locating the MetroChange test kiosks in transit points of exit from the city, such as the JFK Airport, or Grand Central Station.

User Scenario
User comes to the Metrochange kiosk, swipes a card and chooses an option to donate the leftover money on the card. The donation is counted once the card is deposited inside the kiosk.

There is a kiosk with Arduino, ethernet shield, LCD screen, IR transmitter and receiver, and magstripe reader.

We went through several iterations starting with a Windows-based setup that was reading magstripes as sound and then converted it to binary, then there was an iteration with an Adafruit-recommended cardreader which was not fast enough for our purposes. Finally we have a working prototype with an eletric goldmine surplus cardreader that does the job.