~/ work / cashless-nfc cashless NFC · ruggedised Android · payments

Wristbands as wallets,
tap to pay.

Trainspot KK · for the Pommery champagne house

A cashless mobile payment app deployed at the Pommery champagne house. Visitors top up their NFC wristband on entry, then tap at bars and stations to spend the pre-loaded credit. The Android client runs on ruggedised Famoco handhelds.

// on site

A staff member holds a ruggedised Famoco handheld against a guest's NFC wristband at a bar counter, under blue event lighting. — A guest pays with an NFC wristband. The Famoco terminal confirms the payment.

Close-up of the handheld screen showing a Transaction successful confirmation after a payment. — A guest pays with an NFC wristband. The Famoco terminal confirms the payment.

// context

The system needed fast, straightforward operation for busy event staff, reliable outdoor performance and protection against wristband cloning. It also needed to preserve balances if power was interrupted during an update.

// our role

Mobile and embedded engineering for the Trainspot KK team: custom Android client on Famoco ruggedised handhelds, NXP UltraLight C personalisation with per-card 3DES key diversification, counter-based dual-buffer atomic transactions to protect wristband balances if power is interrupted during an update, and native JNI handling of the master keys to keep them out of the Java heap.