Atrium: NFC Smart Lock for Vacation Rentals

Simplifying Vacation Rental Check-ins

The idea for Atrium hit me during a frustrating experience on a trip to Argentina in 2015. After a long day of travel, my friends and I arrived at our Airbnb only to find that the keys weren't where they were supposed to be. We ended up waiting for hours, unsure of what to do. It was a mess, and it made me realize there had to be a better way to handle vacation rental check-ins.

The Problem

The main problems I wanted to solve were:

• Getting rid of the hassle of physical key exchanges or complicated lockboxes, especially for international trips
• Creating a tech-driven solution that could work for any vacation rental

Atrium is a comprehensive smart lock system designed to revolutionize the check-in process for vacation rentals. Here's how it works:

• Guests receive an NFC-enabled Atrium card that works with all Atrium locks.
• Hosts and guests use a mobile app to manage bookings and access.
• The system uses cloud infrastructure to manage and verify access rights in real-time.
• The lock is designed to be easily installed on existing doors with a deadbolt.

Key Features

• One card works for all participating vacation rentals.
• Guests can access their rental immediately upon arrival.
• Seamless integration with popular vacation rental platforms.
• If your phone dies, you will still be able to check-in as NFC is passively powered.

Technical Architecture

Here's an overview of the key components:

Mobile Application (iOS, not implemented)

• Handle user authentication, booking management, and NFC card activation
• Communicate with the backend API for real-time access control

Lock Firmware (C++ / Arduino)

• Custom firmware for the lock mechanism
• Integrates NFC reader for card detection
• Implements local caching for offline functionality

Backend (Cassandra on Heroku)

• Scalable NoSQL database for storing user data, bookings, and access logs
• Chosen for its high write throughput and horizontal scalability

Communication Protocol (AWS IoT / MQTT)

• MQTT protocol for efficient, low-latency communication between locks and the cloud
• AWS IoT for managing device connectivity and message routing

Cloud Infrastructure (AWS)

• Lambda functions for processing access requests and managing business logic
• API Gateway for RESTful API endpoints
• S3 for storing static assets and logs

Security Measures

• End-to-end encryption for all communications
• Token-based authentication for API requests
• Regular security audits and penetration testing

• Sketched out the initial idea and system components.

Hardware Prototyping:

• Started with an off-the-shelf battery powered lock
• Stripped it down to essential components (battery and motor)
• Designed and 3D printed a custom outer housing

Firmware Development:

• Wrote C++ code for Arduino to control the lock mechanism
• Integrated NFC reader functionality using PN532 NFC module

Backend Infrastructure:

• Set up Cassandra database on Heroku for data storage
• Implemented AWS Lambda functions for business logic
• Configured AWS IoT for device communication

Arduino:

• Started with an Arduino Uno for initial proof of concept
• Used PN532 NFC module for NFC communication
• Integrated basic servo motor for lock mechanism

LinkIt ONE by Seeed Studio:

• Transitioned to LinkIt ONE for its built-in GSM/GPRS, Wi-Fi, and Bluetooth capabilities
• Allowed for more advanced connectivity options and power management

3D Printed Housing:

• Created multiple iterations of 3D printed housings for prototyping using Autodesk Inventor
• Refined design for aesthetics and practicality

Journey to Shenzhen: Understanding Manufacturing

To gain deeper insights into the manufacturing process and explore production possibilities, I took a hands-on approach:

Alibaba Supplier Research:

• Contacted multiple lock suppliers on Alibaba
• Conducted video calls to discuss customization options and manufacturing processes

Trip to Shenzhen:

• Flew to Shenzhen, China - the hardware capital of the world
• Visited several factories specializing in smart lock production
• Spent time on factory floors, observing assembly lines and quality control processes

Key Learnings:

• Gained understanding of mass production techniques for IoT devices
• Learned about quality control measures in hardware manufacturing
• Explored options for customization and branding of existing lock designs

Prototype Refinement:

• Used insights from factory visits to refine Atrium's design for manufacturability

While Atrium remained a prototype, I'm still optimistic that the smart lock for vacation rental space is an untapped market, with the following benefits:

• Eliminating the need for physical key exchanges or complex lockbox systems.
• Allowing hosts to manage multiple properties more effectively
• Providing a consistent and hassle-free check-in process across different rentals, which should increase bookings and retention

To take it a step further, it would be cool to integrate with transit cards as the technology is the same:

• Develop a universal NFC card that combines Atrium access with popular transit cards (e.g., Oyster, Clipper, Suica)
• Create partnerships with transit authorities for seamless integration
• Implement a mobile app feature to manage and top up multiple transit cards
• Enhance traveler convenience by reducing the number of cards needed during trips