Tap2Pay

In an era where contactless payments and digital money are at the forefront, the conventional methods of digital transactions via QR codes or long public key entries often feel cumbersome. Unlike the swift tap of a credit card, these methods disrupt the user experience. Tap2Pay Wallet emerges as a solution to this hurdle by employing ultrasonic communication between devices to facilitate transactions. With Tap2Pay, two smartphones in proximity can interact using ultrasonic signals—inaudible high-pitched sounds—to execute a transaction, eliminating the need for scanning or typing. It's the seamless credit card tap experience recreated for digital currency.

The Tap2Pay app architecture is segmented into three core components, ensuring a seamless and responsive mobile user interface, while effectively handling the ultrasonic data encoding and decoding processes essential for the transactions.

Front-End: Built with React-Native and Expo Go, ensuring a user-friendly mobile experience for both iOS and Android platforms. Ultrasonic Data Processing Server: A locally run Python server was developed to bridge the gap between the front-end and the ultrasonic data processing, as SDK integration directly with React-Native presented challenges. This server manages all ultrasound encoding and decoding, acting as an intermediary. Transaction Management Server: A Typescript server was established to manage the interactions between the front-end and the Safe SDK, ensuring smooth transaction processes. The division of tasks among these components allowed us to overcome limitations encountered with Expo Go, particularly in handling ultrasonic data. The journey enriched our understanding of ultrasonic encoding/decoding protocols, the intricacies of sound frequency management to maintain inaudibility, and strategies to work around technology stack limitations in a hackathon setting, especially in mobile app development.